[Tihsho]

Rather than go on in another persons thread and hijack it, I figured it was time to pull this out and put the rest of the discussion in its own topic. Figured that conceptually this was a 'General Discussion' topic, but since I'll get into some nitty gritty technical details and I'll be using some insight from what I'm seeing first hand with my ventilation experiment that I'd put this under 'Parts and Construction'.

Note to the Reader:
For simplicities sake I'll put it this way, if you're setting up an enclosure for the sole purpose of housing darts and not looking for an aesthetic display, this thread may not be 100% for you. Ventilation is important, but you can 100% get away with a decent ventilation strip as part of your glass lid and you should be ready to roll without additional hardware and enclosure complexity.

So to recap a few things here let me quote my post from the How much should the drainage layer be above the water level? thread.

One thing I think is gravely overlooked within this hobby is active ventilation. There are a lot of things that can be accomplished and provide a healthy ground for darts as well as more lush flora, but it just takes additional work and hardware. I think a lot of people are focused on the whole "glass cage" aspect and don't like to admit that there is a further step that can be taken as to no be limited by an enclosed glass box with passive air flow.

The hobby has thankfully moved from being stuck with solely an enclosure, a spray bottle and then the right song and dance to keep things going to actually moving with the age of technology and leveraging automation. I bet some of the best Viv's that we see wouldn't look as great without having automated misting! Now I think we just need to take it to the next step and promote automated gas exchange rather than limit ourselves to convection. Yes, fans internal to circulate air is great, but if the overall air within our glass boxes are old stale air, what's the point? We need to be able to safely simulate natural airflow as well as provide fresh new air inside the enclosures without having to remove lids regularly and open doors. I can't tell you how many posts I've read back in the day that focused on 'sealed' enclosures that limited the external gas exchange to doors opening for feeding time. Thankfully someone(s) took the time to experiment and provide facts that fresh air exchange within our Viv's is vital for both Flora and Fauna.

When it comes to tropical epiphytic mosses, yes damp conditions are ideal for their growth, but keep in mind in nature, that damp condition is promoted generally with shade and regular rainfall. Oddly enough, some of these mosses appear in the same areas that our beloved Darts are local to. Setting up an enclosure and placing moss where there is too high of heat/wicking of moisture from the moss to another surface will always leave the moss on the losing side. Due to that we need to place the moss where it would most likely appear naturally once our hardscapes are setup for the best growth. The issue is that Earth isn't encapsulated in a container with poor gas exchange, so why limit our enclosures?

From here we will be discussing the applications of passive and active venting. Passive venting being that the vents are built into the lid of the enclosure and convection is used to draw out old/stale air from the top of the enclosure and fresh air is being pulled in from lower vents. Active venting being that mechanical fans are being used to draw out the air from the enclosure at a higher rate than convection. For an idea of what convection is, for those that don't know, take a look at this simple sketch of an Exo Terra:

What you're seeing here is room air (blue arrow) being pulled in through the front vents. This happens because as the lights heat up the top of the enclosure the warmer air within and above the enclosure (red arrows) rise. Due to this as the room air enters, it mixes with the enclosure air (yellow arrows.) As long as there is a temperature differential (generally only happens when lights are on) the convection process will always happen.

Two things that are controversial in this hobby begin with two parts of the construction and the aesthetic goals we are after:

1 - Glass tops vs screen lids vs combo of the two
2 - To add a water feature or to not add a water feature

For a majority of us with Vivs we know that an enclosure with 100% screen tops are just not going to work. In order to compensate for the enclosure environment to be different than our home environment(s) we must go through and somewhat close off the lids of out Viv's with glass. The addition of glass helps us retain humidity rather than lose it quickly to our homes atmosphere. Being that where we live, as well as out homes HVAC setting plays a big part into how our Viv's microclimate turns out, this discussion cannot ever be taken with a cookie cutter approach, but with that said I'm trying to find a way to have a solution that can be taken and then dialed in with your home climate.

Let me start out by laying out the variables I'm dealing with in my homes HVAC environment. Year round I keep my home on the cool/cold side (68 degrees F), and the average humidity in my home ranges from 30%-45%. Part of my home HVAC unit includes a huge dehumidifier that cranks out gallons of water daily into a drain. The whole reason I run a home wide dehumidifier (as well as room centric dehumidifiers) are solely because of all the aquariums I have at home. One room that I have dedicated to aquatic/emersed plants as well as my fish and invert breeding projects has an additional dehumidifier for obvious reasons, on top of that my basement also has an additional standalone unit just due to the fact my basement is 85% underground so rather than have the HVAC system cranking more than it does, I leverage an additional dehumidifier to keep down the ambient humidity levels. In summation:

Home Average Year Round Temp: 68F **
Home Humidity Range: 30-45%

** I have some rooms that run warmer, such as my office due to computers and other tech that generate heat and I keep my office door shut to keep my cats from getting in and messing with stuff

Ok, so why did I mention my home microclimate specs? Why does it even matter? Well at the end of the day, without significant investments into cooling or a dehumidifier, whatever your home's microclimate is will be the coolest/least humid value you can expect to get your enclosure. So if you have a home that happens to run 'wet' at say 75% humidity and you keep your ambient room temps set to 73 degrees F you're not going to be able to have an enclosure cooler than 73 degrees F (expect them to be warmer anyways due to heat being radiated by your lights) and the air cannot pull out your moisture being vented from your Viv. One key thing to remember about all of this is that the best you can get for a microclimate would be a value at equilibrium. Now with that said lets take a look at how we can use your home's microclimate to manage your Viv's microclimate.

As I stated before most Viv's are going to run warmer than what a room's ambient temperature is. Between the insulation of glass as well as the heat being radiated from a light fixture, you can always expect your Viv to be at least a few degrees warmer. We can control the heat radiation simply by running LED lights rather than incandescent or fluorescent bulbs. The difference between running LED (that hopefully has it's own heat sink and isn't 100% directly on the glass) and either of the two other bulbs can be a delta of either a couple degrees being input from an LED to 10+ degrees being input by either of the other two light sources.

Now that we have heat covered, lets move to the next topic; humidity. Humidity is pretty simple, the more moisture in an environment, the more the air will be saturated with water bringing up the ambient humidity of an environment. So if we have a basic enclosure with passive venting that's sole source of humidity is misting, that setup will generally show a flux in humidity over time as fresh atmospheric (room) air is generally introduced through convection. As the water evaporates and is pulled out with convection, the ambient humidity will drop. In the case of another basic enclosure with passive venting that has misting AND a water feature, you will notice that the ambient humidity is generally always higher as there is a constant source of water. Unlike the enclosure that only has misting, you will never be able to attain low levels of ambient humidity. Keep in mind, without something circulating the air within any enclosure you will have what are called humidity gradients. What this means are that the lower areas of your enclosure will generally run more humid than the top, and that is due to humid air being heavier and falling to the lower levels of your enclosure. Having internal fans circulate the air will assist with the enclosure having one humidity gradient, where as no fans mean you will have very obvious layers of gradients.

So how can we shorten the time it takes to drop the humidity in our Vivs? Well it's simple! Let's remove the larger passive vents at the top of our enclosures and replace them with smaller vents that attach to fans. Unlike passive venting which only speeds up as additional heat is applied for the convection process to speed up, we can control the amount of air being pulled out of our enclosures with fans by increasing or decreasing the fan speeds (technical applications on this will be a post of their own.) Before you ask, "Tihsho, why do we want to connect the fans to smaller vents?" Well, if we don't there will be a ton of air being circulated through the Viv, pulling out large amounts of air quickly means our environment lacks stability. Going from a 80% humidity down to 50% humidity over time will impact what is within the Viv less so than going from 80% to 50% instantly. Mind you, we are looking for speed in this process, but we want to be able to manage it. Large fans on large vents on a 'small' enclosure would just be too chaotic for anything living in the enclosure. Why would we even want to do this? Well, applying active venting means we can control the airflow through the Viv which has been proven to be beneficial for both Fauna and Flora. Not only that, but it can be used to keep glass from fogging or getting internal condensation. More so, for those of us who want to tinker in the realm of water features, this gives us the best method of lowering the humidity of out enclosures without having to build a greenhouse to house a puddle of water. Keep in mind when I talk about water features here, I'm talking a puddle that takes up around 1/6th if not less of the overall floor space of your enclosure.

Now with active venting being added to an enclosure we can work on automating the environment, keep in mind for those who are against automation you have to remember most people use automated misters... So don't look at this like some black magic that's evil.

I plan to keep up with this thread as I go through and update my personal build thread with other details.

 

[Leite02]

A "like" for the great work you have done.
Although I must admit that, due to my problem with the language, at times I have felt like this:

 

[Socratic Monologue]

Now with active venting being added to an enclosure we can work on automating the environment, keep in mind for those who are against automation you have to remember most people use automated misters... So don't look at this like some black magic that's evil.

Mmmm....not the same. Active v. passive isn't the same debate as automated v. manual. Passive ventilation is automated, since I don't force air in with my hands whenever it is needed -- it happens automatically, as a function of the heat generated by the automated-with-a-timer lights. Both a MistKing and a hand mister are active misting -- passive misting might be those old school vivs that are sealed tight and the water condenses on the lid and falls back into the viv.

A person could automate passive ventilation, too, by installing covers on the vents that open and close via a humidistat.

Keep in mind, without something circulating the air within any enclosure you will have what are called humidity gradients. What this means are that the lower areas of your enclosure will generally run more humid than the top, and that is due to humid air being heavier and falling to the lower levels of your enclosure. Having internal fans circulate the air will assist with the enclosure having one humidity gradient, where as no fans mean you will have very obvious layers of gradients.

Are humidity gradients detrimental? I've read of people exploiting these gradients to grow plants with varying humidity preferences in the same viv. Also, offering motile inhabitants choices of microclimates is generally beneficial.

Cool thread, BTW.

 

[Tihsho]

Mmmm....not the same. Active v. passive isn't the same debate as automated v. manual. Passive ventilation is automated, since I don't force air in with my hands whenever it is needed -- it happens automatically, as a function of the heat generated by the automated-with-a-timer lights. Both a MistKing and a hand mister are active misting -- passive misting might be those old school vivs that are sealed tight and the water condenses on the lid and falls back into the viv.

Good catch! I was going to get into this later, but I figure I'll get into it now since you brought it up. Yes, the passive 'vent strip' is naturally automated, but it has it's limitations. To create more flow through the viv, you're going to have to do one of two things, either increase the vent area OR in most cases speed up convection which isn't ideal as that involves adding more heat to the enclosure. So with that said, the only valid option is to increase the vent area so that more atmospheric air has a chance to come in contact with the air within the Viv. As for the active and passive misting... I think there might be confusion as I didn't mention anything about active or passive misting, only the difference between misting being a source of humidity or a body of water.

A person could automate passive ventilation, too, by installing covers on the vents that open and close via a humidistat.

Very true, this can be used to increase the ventilation area to purge humid air faster, and this is done in Greenhouses and a very common practice. In the application for a Viv, this isn't ideal as throttling the venting area will take up significant space. I originally looked into designing an iris style vent that was actuated with servos, but the kicker here was the surface area this took up. Not only did this take up a ton of space, but it also limited the areas of which I could suspend a light. The shadowing from these iris vents would have been too much for such a small environment. This only left active venting that can be controlled with an IoT board with a micro processor or an ABC. This is where the automation of active venting was going.

Are humidity gradients detrimental? I've read of people exploiting these gradients to grow plants with varying humidity preferences in the same Viv. Also, offering motile inhabitants choices of microclimates is generally beneficial.

Cool thread, BTW.

I would say humidity gradients in our tiny glass boxes (compared to nature) are detrimental! Not only do these gradients provide microclimates within the Viv that Darts can post themselves in for comfort, but in the case of a lot of the rarer tropical species of Flora that are tied into the Dart hobby without the gradients success rates for said plants would be slim. Due to this I don't understand why a lot of people run internal fans in their setups 24/7. The internal fans should only be set to run for short periods of time to create air flow and stop. Breezes are natural in nature, constant breezes or presence of wind is extremely rare, especially in a Tropical environment.

 

[Socratic Monologue]

I guess my motivation behind noting the false analogy is that it is entirely consistent to use automated misting and find flaw in active venting -- so I'm disputing the 'black magic' claim.

I'm still confused about this:

I would say humidity gradients in our tiny glass boxes (compared to nature) are detrimental! Not only do these gradients provide microclimates within the Viv that Darts can post themselves in for comfort, but in the case of a lot of the rarer tropical species of Flora that are tied into the Dart hobby without the gradients success rates for said plants would be slim.

Are you saying that humidity gradients are good or bad? In your opening post the implication was that humidity gradients are bad, and this supposed fact supported the use of active ventilation:

Keep in mind, without something circulating the air within any enclosure you will have what are called humidity gradients.

 

[Tihsho]

I guess my motivation behind noting the false analogy is that it is entirely consistent to use automated misting and find flaw in active venting -- so I'm disputing the 'black magic' claim.

All I ask is you to be open minded. I'm going to be providing tested methods so there will be actual evidence to prove otherwise

I'm still confused about this:

Are you saying that humidity gradients are good or bad? In your opening post the implication was that humidity gradients are bad, and this supposed fact supported the use of active ventilation:

Sorry, I was rambling at that point so I can see the confusion. I'm all for humidity gradients, being able to have high and low spots within a Viv is ideal to replicate a 'natural' environment. What I was getting at in that one sentence was to say if you have calm/still air (i.e. the no internal circulation part) you actually have gradients. When there is an internal fan you lose the gradients as air is unable to settle, so overall 90% of your Viv will be at almost a constant value. The active ventilation, which will be regulated by bursts of vacuum from the fans will temporarily stir up the gradients, but once the air settles the gradients will still exist. I might need to go back and reword what I wrote as I'm not saying anything about gradients being bad.

Also, let me clear up something. The active venting isn't to reduce the gradients, it's more so focused for those who are looking to have water features, but at the same time not have a 10-15% higher overall humidity. The purpose of active venting is to go through and drop the ambient microenvironments 'overall' humidity value to which when the fans are off, the humidity is allowed to rise to a specific threshold. Does that make more sense?

If we were to compare an enclosure with no water feature to an identical one with a water feature, I'm estimating that on the high end, the humidity would be 10-15% higher in the Viv with the additional water volume. So if our goal is to keep our Vivs at say 50-75% humidity (prior to misting) the ambient of a water featured Viv I'm estimating would be around 60-90% pre misting. With the ventilation, we should be able to attain the 50-75% range as the additional hardware will be able to pull in more fresh air then an enclosure that just relies on passive convection for ventilation.

 

[Socratic Monologue]

A big part of being open-minded is avoiding using, and being swayed by, argumentative fallacies, so no worries there.

One concern is that novice keepers see arguments in favor of 'piece of technology A' and think they need it to keep frogs, when in fact they don't need it, and would do better without it in most vivs. It is good that you inserted this disclaimer:

Note to the Reader:
For simplicities sake I'll put it this way, if you're setting up an enclosure for the sole purpose of housing darts and not looking for an aesthetic display, this thread may not be 100% for you. Ventilation is important, but you can 100% get away with a decent ventilation strip as part of your glass lid and you should be ready to roll without additional hardware and enclosure complexity.

but the phrase "get away with" strongly implies that passive venting is some sort of tolerable second-best ("this recipe specifies fresh basil, but you could get away with dried"), which isn't at all true. Active venting (or active circulation, which more keepers might have use for than active venting) definitely has its place in certain builds, and for this reason alone it is really valuable that you've taken on a thread on the subject, but portraying it as a tool to make possible more complex builds -- rather than something that solves a supposed fundamental airflow problem -- would be more accurate.

Looking forward to the data!

 

[Tihsho]

but the phrase "get away with" strongly implies that passive venting is some sort of tolerable second-best ("this recipe specifies fresh basil, but you could get away with dried"), which isn't at all true. Active venting (or active circulation, which more keepers might have use for than active venting) definitely has its place in certain builds, and for this reason alone it is really valuable that you've taken on a thread on the subject, but portraying it as a tool to make possible more complex builds -- rather than something that solves a supposed fundamental airflow problem -- would be more accurate.

Looking forward to the data!

Depending on what the results turn out, this option may make passive venting a "tolerable second-best", but I don't have enough data to support that statement at this time. I'm looking at the automation of venting with fans as a parallel to automated misting. Yes, we can happily go through and mist by hand, but I would say that the new 'standard' for a majority of those with Vivs (with or without darts) is to go with an automated system. Not only is it a more reliable and track able addition to the Viv, but coupled with the nozzles being used it not only provides finer misting (specifically MistKing), but it allows us to get water throughout the viv more accurately all while using less water. After using MistKing products for about 10 years I can hands down say that their product has optimized misting and projected the hobby in the right direction. Lot of people may get into MistKing for the convenience factor (lazy factor) and that's a big reason to why they like the product without pushing back on automation being 'black magic'. In the case of venting, yes it's not like we sit there and waft air into our Viv's as a common daily practice, but I believe it's something we as hobbyists have overlooked.

Just like any tool, you have to use it correctly. At this point I'm trying to dial in what is 'correct' for my Viv which may or may not be transferable to others. That's where the configuration of automation comes in. Once the hardware is available, anyone can go out and put a kit like this together and they can dial in the fan speeds to meet their CFM requirements for their enclosures. The caveat on this is that true automation where there is a 'brain' with code to determine when to kick the fans on/off is a long way away. Based on how digital hygrometers work, we all know the slightest drop of water on them will throw off the entire reading. Due to that, this system will more so be setup like a MistKing with a seconds timer until something can be figured out to measure humidity reliably. Last thing we need is a crashed Viv due to a drop of water on a sensor causing the fans to run until the environment is too dry.

 

[dwllama]

Looking forward to seeing what you find out with all this and what kind of results you can achieve.

 

[Tihsho]

At this point I'm waiting on some more fans to arrive. I have the rest of the 3D printed parts completed and I'll go through and install those soon. After that it should be as simple as installing the fans, whipping up a wiring harness and then going from there.

Generation 1 of this test is going to be 2 pin fans that are regulated to be on/off. Why? Well I have the relays to do it, the CFM of these fans are low being that they are 40mm 12V fans, and it gives me a base set of code to work on and get running. One thing I'm going to do is setup a few 'flags' within the Viv to see if I can visually show the airflow. Capturing the visual convection might be tough as that airflow is slow. With the fans on, we might be able to see a rustle of some of the flags from the inlet, and on other places I tag them in the Viv. Initially, I checked the inlets of where the bushing is inside the Viv and a piece of tissue paper was easily pulled into it, so the vacuum from the fans is pulling a mild, yet decent, amount of air. I'll also work on seeing if I can get some time lapses of the viv pre, during, and post misting to show how the additional airflow is helping the Viv breathe.

 

[dwllama]

Depending on how long you intend to have your flags set up, tissue paper might break down pretty quickly. I was thinking bits of plastic ribbon, but actually, pieces of grocery bags might work, too.

 

[Tihsho]

Depending on how long you intend to have your flags set up, tissue paper might break down pretty quickly. I was thinking bits of plastic ribbon, but actually, pieces of grocery bags might work, too.

Good point. The tissue paper I used was for a quick test. What I'm currently using now are strips of wax paper.

 

[Encyclia]

Watching this with interest. I will say that your characterization of gradients in a viv maybe a little more subtle in practice, though I think you are headed toward a more thorough understanding. In your first post, you seem mention a single, tank-wide gradient of moisture. There probably is one of those at least some of the time and in most tanks, but I suspect that a tank set up with passive ventilation (as you so elegantly demonstrate in your graphic) or with active ventilation via fans sets up a series of micro gradients in the tank. These micro gradients are associated with tiny wind shadows. Really, everywhere is subject to humidity variations because of non-laminar flow of air, broken up by various surfaces and hardscape elements in the tank. After a while, you will know which parts of your tank tend toward wet and which are drier. Eventually, you will either take advantage of this and actively plant things that enjoy different conditions (light/shade and misting are an element of this, too) OR the plants will end up sorting themselves based on their preference. Regardless of how hard you try to control these elements with fans, you will end up with the same results. Some places are going to be drier and some wetter. This can occur over the course of an inch or vary from one side of tank to the other, but you are going to end up with that situation no matter what you do. This is not a problem or criticism. I think this is the way tanks ought to be and the way nature is (probably to a lesser extent). It's also good for the frogs to be able to choose their microenvironment.

I think that the stuff you are trying to do will work just fine. It all supposes that there are rails on the inputs of moisture and outside air. If you try to pipe too much dry air into the tank, you will not have happy frogs or plants. Likewise, if you add too much moisture from misting or a water feature, you will end up pushing things too far into the humid range and the frogs will not be able to cool evaporatively. You will still have moisture gradients in both situations, but they won't be stretched across the range that is natural for the frogs.

Anyway, please don't interpret anything I am writing as criticism. I wish you all the best in your experimentation and will look forward to seeing your results. Maybe you will figure something out that will change how we do things in the hobby. I like to think that if that is the case, members of this board will be willing to try it out and embrace it if it works for them.

Mark

 

[Tihsho]

I think I need to figure out how to word things better on the initial post... No matter what, the enclosure will have humidity gradients (this is a good thing), but as you stated and why I mentioned this isn't something that someone can just copy and expect the same results, certain parts of an enclosure will always tend to run higher with humidity. Areas that will tend to run more 'wet' will be obviously places where collections of water exist, as well as porous material that have absorbed water (wood and hygrolon areas in my case.)

When talking about playing with the 'global' micro environments humidity, I was specifically focusing on bringing dryer air in to replace the saturated air so that the ambient internal air (without airflow) can act like a sponge before more air is pulled in to replace it. I'm sure that sentence doesn't make 100% sense and I'm trying to find a way of diagraming it to make it clearer. In my viv currently with a heavy misting, a bowl of water (to represent my water feature puddle) and using passive (no fan) airflow my peak humidity gets to about 80% and it can take 8+ hours to drop down to the 60-70% range. With the active fans gently pulling out the hotter air in the Viv (from the top), I'm able to bring the Viv down to 55% humidity in about 2 hours with the 12V fans overpowered at 13.5V or to 55% humidity in 3.5 hours at 12V. The goal isn't to turn the Viv bone dry, but more so allow the damp surfaces to dry out so that the humidity gradients can exist. If I don't use active venting the enclosure will be at 80% humidity for so long that that is the lowest humidity range for the frogs to possibly escape to. By introducing fresh and dryer air, this allows for the lowest humidity range for the frogs to find to be around 55%.

I currently have Digital Hygrometers placed at the lowest dry point in the Viv (so the substrate layer) and one at the highest point (on top of a piece of wood) so I can keep an eye on the micro environments. On top of that since I'm using a manual misting method at this point, I pull the Hygrometers before misting to make sure that they won't get water accidently in the sensors. After misting I relocate them in there spots and have been gathering data from there.

 

[RyanD]

Very interesting! I do wonder how much room specific variables come into play. It would be nice to have more control over that in these "created environments".

Ive just started with a MistKing system on three exo terras. I did place window screen vents front AND back, so it will be interesting if the natural, passive ventilation will suffice to sort of provide a level of automation. The duration and frequency of MistKing would have a profound impact I imagine, so I'm counting on the MistKing to be the one thing that manages the environment.

That being said, it would be really nice to have a reliable and controllable way to maintain those microclimates more predictably.

Sent from my FRD-L04 using Tapatalk

 

[Keroroo™]

For an idea of what convection is, for those that don't know, take a look at this simple sketch of an Exo Terra:

What you're seeing here is room air (blue arrow) being pulled in through the front vents. This happens because as the lights heat up the top of the enclosure the warmer air within and above the enclosure (red arrows) rise. Due to this as the room air enters, it mixes with the enclosure air (yellow arrows.) As long as there is a temperature differential (generally only happens when lights are on) the convection process will always happen.

noobs ask :
are there any significant effect if we set air flow in the opposite direction like this pict?

which one is better?
TIA 🙏