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Discussion Starter · #1 ·
I'm wanting to buy an RO filter that would help with keeping my misters and glass a little cleaner. I'm not looking for any high tech salt water aquarium "like" setup, just something that will provide much cleaner(less minerals) water than just straight out of the tap.


I have never used RO filters so I guess I just need a little direction as to what brands, filters, etc; to look for.
 

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It's my opinion that a carbon-block prefilter and an RO membrane are all you need for your average tap water. If you're using well water you'll need some sort of sediment filter in front of that.

The membrane produces nearly perfect water all by itself. What you need the carbon-block prefilter for is to remove chlorine, which will eat away at an RO membrane and create openings for solids to fit through.

I've been using the same $75 unit with a prefilter and a postfilter (which I consider useless and never replace) for seven years or so. I've been very lazy about replacing the prefilter -- you're supposed to do it every 6 months, and I do it maybe once every 18.

Today I still get these results on the TDS meter:

tap water: ~125 ppm
Brita filtered water: ~75 ppm
RO filter: under 15 ppm

I can't imagine anyone but a scientist or an engineer needing better than 15 ppm.

So, yeah, don't waste money on anything fancy.
 

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If your city water runs a TDS above 150, it is helpful to have a sediment filter to keep your carbon block from getting clogged up with sediment.

Sediment cartridge, carbon block, RO membrane.

I have used a couple units from airwaterice and every one has worked well and lasted. I don't have any affiliation with them, and some of the dendroboard sponsors also sell acceptable RO units.

Stay away from anything with the Coralife name on it.
 

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Discussion Starter · #4 ·
It's my opinion that a carbon-block prefilter and an RO membrane are all you need for your average tap water. If you're using well water you'll need some sort of sediment filter in front of that.

The membrane produces nearly perfect water all by itself. What you need the carbon-block prefilter for is to remove chlorine, which will eat away at an RO membrane and create openings for solids to fit through.

I've been using the same $75 unit with a prefilter and a postfilter (which I consider useless and never replace) for seven years or so. I've been very lazy about replacing the prefilter -- you're supposed to do it every 6 months, and I do it maybe once every 18.

Today I still get these results on the TDS meter:

tap water: ~125 ppm
Brita filtered water: ~75 ppm
RO filter: under 15 ppm

I can't imagine anyone but a scientist or an engineer needing better than 15 ppm.

So, yeah, don't waste money on anything fancy.
Carbon, would you mind letting us know what brand you have and where you got?

If your city water runs a TDS above 150, it is helpful to have a sediment filter to keep your carbon block from getting clogged up with sediment.

Sediment cartridge, carbon block, RO membrane.

I have used a couple units from airwaterice and every one has worked well and lasted. I don't have any affiliation with them, and some of the dendroboard sponsors also sell acceptable RO units.

Stay away from anything with the Coralife name on it.
I do not have a TDS meter so not to sure how bad my city water is.

I was looking at this site: Build Your Own RO System - English


It's a build your own part of their website.

Stage 1 offers:5 micron and 1 micron sediment

Stage 2 offers: same as above plus 5 micron and 1 micron carbon block

Stage 3 offers: same as above(carbon) and Deionization Resin(color changing)<~~~~ whatever that means and a Chlorplus carbon block

Stage 4 (membrane) offers: 75 GPD which is WAY MORE than I need but the lowest they offer

Stage 5 offers: single or dual DI


I understand all those stages are overkill but do I need the DI for anything? and I think the Stage 1(5 micron sediment) would become clogged very quickly, wish they offered like a 15 or 20. And I assume that I would just need the 5 micron carbon block.

I really don't see the need for anything that is a 1 micron, please correct me if I'm wrong.
 

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For your needs, I was thinking something more along the lines of Aquarium Water | Reverse Osmosis | RODI Water | ReefKeeper Water | RO MIGHTY MITE SYSTEM 50GPD
The only issue with the one I just linked is that it has the small inline cartridges, you may have a hader time trying to find replacements if you dont want to get your replacement cartridges from the same place.

The one you linked to, after I added a 5 micron sediment, 5 micron carbon, and 1 micron carbon (you really don't need the second carbon block, especially for your application), and the 75 GPD membrane the total was $104.96 and I didn't include an auto shutoff valve or any other valves, hosing, or sink/watersupply adapters.

This one is more filter than you need, but if you wanted full size cartridges to make it easier come replacement time theres also this one: Aquarium Water | Reverse Osmosis | RODI Water | ReefKeeper Water | Compact 75 GPD Reefkeeper RODI

As far as DI goes, for your purposes, it is not necessary. On Carbonetc's TDS chart, DI water would ideally have a TDS of zero, but for most applications anything <5 is considered acceptable.

Added note: DI resin would be run after the RO membrane to remove the last few ions remaining in the water (TDS) after the RO filtration
 

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You don't need any 1 micron filters, the RO membranes are usually rated for 5 micron prefilters IIRC. Going down to 1 micron in your prefilters puts less wear and tear on your RO membrane so that hopefully you can get closer to the high end of the 3-5year lifespan that RO membranes are rated for.
 

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My TDS meter is probably not too precise, but it gives me roughly what I need: Amazon.com: HM Digital TDS-EZ Meter/Tester, Water/ppm/Purity/Filter: Home & Garden

I bought it because I had been fretting for years over whether my RO membrane was still good. Without the TDS meter I probably would have bought another membrane or RO unit just to be safe, though it turns out I didn't need to. So I guess it paid for itself.

Since my RO unit has a postfilter I can't recommend it. It's also big and awkward -- screwing it to a wall is the only way to keep it from falling over. If I could do it over again I'd get something more streamlined, like what Rhesus Feist is recommending.
 

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That TDS meter looks similar to the one I use, we don't really need to be all that precise for our purposes in vivs, or even in reef aquariums (unless you have a known polutant in your water source). It is a handy piece of equipment ot have to help make sure your filters are doing waht they are supposed to do.

You may very well get more than 5 years out of an RO membrane using them for vivs. That 3-5 year life span is based on incoming water only being prefiltered to 5 microns, and it is also based on 50-75 GPD of production every day. I go through about 75 gallons per week with 4 smaller (all less than 50 gallons) fish tanks, 2 vivs, and a wire rack full of tropical plants.
 

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One more point to consider in all this is your water usage. Every RO membrane I've ever come across has a rejection rate of 95-98% This means that 95-98% or more of the water that comes in to the membrane gets rejected and flushed down the drain (or where ever you choose to dispense of your waste water). Just something to keep in mind with all this.
 
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