Getting back into darts, lifes busy + I work late often... All my aquariums are arduino controlled... So the Viv's going that way too come heck or high water 
Here I go again with this project... Open source, everything should be cheap and easy to find, any idiot (ie me) with a soldering iron, should be able to replicate it and adjust to his needs.
Shopping list (ok well I have a lot of this lying around) - links are generally to my local geek shop (yeah I said it). You can find them on ebay, sparkfun, any number of other retailers, I just happen to know this site better
Freeduino - brains of the unit 28920 - SB-Freeduino « Products « Solarbotics - you can go with any of the thousand varieties of arduino, just know you're going to want memory, so get the atmega328 at minimum. If you want a multi tank setup, you're going to want one of the MEGAs
Humidity sensor- Sparkfun HIH-4030 50664 - Humidity Sensor - HIH-4030 Breakout « Products « Solarbotics
Temp - DS18B20's in my case, likely you'll be sourcing DS18S20's 35040 - DS18B20+ Temperature Sensor « Products « Solarbotics
Light Dependant resistor - I always run these, there's many days I leave before lights on, and return after lights off... It's nice to have warning, if the lights didn't come on, and it's easy to dump the # to flash - so once output drops 30%, I get a warning to order bulbs...
CDS - CdS Light Sensitive Resistor « Products « Solarbotics
Solid state relays -you'll want one of these for every device you want to control (heater/pumps/lights/nightlights etc) Look for a 5vdc control circuit and size appropriately for amps (don't worry on voltage for the other side, most are 240vac, just do not exceed). Usually cost about 5$ each
So that'll make a functional controller (with a few other odds and ends... Get to those in a bit) But what good is a controller without some interfaces?
2x16 lcd - I wont be using this, I'll be running an ebay one (backlit blue 2x16 off ebay - 3$ vs 50+ ) but they are essentially the same... HD44780 compatible is pretty much all you need; this is where you can pick your preference, they run from 1x8 all the way out to 4x40
21410 - Parallax 2x16 Backlit LCD Module « Products « Solarbotics
And of course, need to have some input for adjustments
4x4 keypad -http://www.solarbotics.com/cad/products/31000/
Usually I build this all on a protoshield 16090 - Freeduino SB-Protoshield « Products « Solarbotics , with the exception of the relays - usually I put those in one of these American Audio PC-100A 8 Switch On/Off Power Center [AA PC-100A] : AVShop.ca, Canada's Pro Audio, Video and DJ Store - However I'll be doing some shopping this time, man have these gotten expensive, used to get them for about 20$.
I'll see if I can have a nice kicad project file available by the weekend with schematics, full parts lists, board layouts the works...
I was thinking I'd just modify one of the reef controller projects' programs for this; this is what takes me forever, I'm TERRIBLE at programming
Anyone want to help?
Basics:
Temp sensors are I2c - 1 wire technology, If I recall, you can connect 64 1-wire sensors to this line... Tech details are here Arduino playground - OneWire
Humidity sensor - simple analog device. Arduino Forum - HIH-4030 Humidity Sensor and Arduino example code? (now if you're doing multiple tanks, you MIGHT want to consider an arduino mega, Could get short on analogs if you want tons of these)
Light dependant resistor - again as above simple analog device How to use photocells, LDRs, CdS cells, photoresistors!
LCD is an HD44780, only problem with it is it chews up pins, so we'll go to i2c, for a port expander - a PCF8574. Library and schematics are over Arduino Forum - My most beloved topic - the PCF8574 with a HD44780
I'm going to try to keep the PWM pins open for dc motor control (ie cooling or ventilation fans)
Code I use on my aquarium controllers - is over here: Code - Reef Projects We almost built these side by side; and worked off eachothers ideas in many cases... Even for a non programmer like me - relatively easy to figure out and modify... There's a ton of stuff in here that can be deleted...
Here's his (much prettier than mine) american dj power center:
I usually go the ratsnest method and stuff my (much smaller) SSRs in between the switches and plugs... But I hear the new versions have less space...
About all that I see that might be left, are float switches for top off/water features/overflow prevention... While those are analog switches, we should be able to implement them on either analog or digital pins, very easily...
Now... I've never been big on internet connectivity for my tanks... But I know some of you are, and you're probably noticing that I haven't really accomodated datalogging (I think a daily min/max is good enough). I know there's enough memory left on my reef's arduinos (which have way more code and sensors) to handle either a ethernet, wifi or bluetooth connections; I know there are ethernet wifi and bluetooth shields already designed and sold... This is where I get back to that whole - I'm no programmer
The way to communicate is designed, just needs someone to come up with a plan on implementation... Be it web apps, emails, whatever... The shields are there, I'll design the control shield so that one can stack a comms shield on top (and work to see if we can't accomodate any pins it might need)
Here I go again with this project... Open source, everything should be cheap and easy to find, any idiot (ie me) with a soldering iron, should be able to replicate it and adjust to his needs.
Shopping list (ok well I have a lot of this lying around) - links are generally to my local geek shop (yeah I said it). You can find them on ebay, sparkfun, any number of other retailers, I just happen to know this site better
Freeduino - brains of the unit 28920 - SB-Freeduino « Products « Solarbotics - you can go with any of the thousand varieties of arduino, just know you're going to want memory, so get the atmega328 at minimum. If you want a multi tank setup, you're going to want one of the MEGAs
Humidity sensor- Sparkfun HIH-4030 50664 - Humidity Sensor - HIH-4030 Breakout « Products « Solarbotics
Temp - DS18B20's in my case, likely you'll be sourcing DS18S20's 35040 - DS18B20+ Temperature Sensor « Products « Solarbotics
Light Dependant resistor - I always run these, there's many days I leave before lights on, and return after lights off... It's nice to have warning, if the lights didn't come on, and it's easy to dump the # to flash - so once output drops 30%, I get a warning to order bulbs...
CDS - CdS Light Sensitive Resistor « Products « Solarbotics
Solid state relays -you'll want one of these for every device you want to control (heater/pumps/lights/nightlights etc) Look for a 5vdc control circuit and size appropriately for amps (don't worry on voltage for the other side, most are 240vac, just do not exceed). Usually cost about 5$ each
So that'll make a functional controller (with a few other odds and ends... Get to those in a bit) But what good is a controller without some interfaces?
2x16 lcd - I wont be using this, I'll be running an ebay one (backlit blue 2x16 off ebay - 3$ vs 50+ ) but they are essentially the same... HD44780 compatible is pretty much all you need; this is where you can pick your preference, they run from 1x8 all the way out to 4x40
21410 - Parallax 2x16 Backlit LCD Module « Products « Solarbotics
And of course, need to have some input for adjustments
4x4 keypad -http://www.solarbotics.com/cad/products/31000/
Usually I build this all on a protoshield 16090 - Freeduino SB-Protoshield « Products « Solarbotics , with the exception of the relays - usually I put those in one of these American Audio PC-100A 8 Switch On/Off Power Center [AA PC-100A] : AVShop.ca, Canada's Pro Audio, Video and DJ Store - However I'll be doing some shopping this time, man have these gotten expensive, used to get them for about 20$.
I'll see if I can have a nice kicad project file available by the weekend with schematics, full parts lists, board layouts the works...
I was thinking I'd just modify one of the reef controller projects' programs for this; this is what takes me forever, I'm TERRIBLE at programming
Basics:
Temp sensors are I2c - 1 wire technology, If I recall, you can connect 64 1-wire sensors to this line... Tech details are here Arduino playground - OneWire
Humidity sensor - simple analog device. Arduino Forum - HIH-4030 Humidity Sensor and Arduino example code? (now if you're doing multiple tanks, you MIGHT want to consider an arduino mega, Could get short on analogs if you want tons of these)
Light dependant resistor - again as above simple analog device How to use photocells, LDRs, CdS cells, photoresistors!
LCD is an HD44780, only problem with it is it chews up pins, so we'll go to i2c, for a port expander - a PCF8574. Library and schematics are over Arduino Forum - My most beloved topic - the PCF8574 with a HD44780
I'm going to try to keep the PWM pins open for dc motor control (ie cooling or ventilation fans)
Code I use on my aquarium controllers - is over here: Code - Reef Projects We almost built these side by side; and worked off eachothers ideas in many cases... Even for a non programmer like me - relatively easy to figure out and modify... There's a ton of stuff in here that can be deleted...
Here's his (much prettier than mine) american dj power center:

About all that I see that might be left, are float switches for top off/water features/overflow prevention... While those are analog switches, we should be able to implement them on either analog or digital pins, very easily...
Now... I've never been big on internet connectivity for my tanks... But I know some of you are, and you're probably noticing that I haven't really accomodated datalogging (I think a daily min/max is good enough). I know there's enough memory left on my reef's arduinos (which have way more code and sensors) to handle either a ethernet, wifi or bluetooth connections; I know there are ethernet wifi and bluetooth shields already designed and sold... This is where I get back to that whole - I'm no programmer