CO2 DIY for 70 gal

[Wiggler 1]

I would like to put CO2 into my 70gal. tank...cant really afford presurized system
I beleive that I would like to make a DIY system and have done a bit of reading on it...if I could ask a few questions it would be great...
1...CO2 should be turned off at night (this is what I have read ) is their a DIY shut off
for a yeast based system, seams to me the yeast will work all the time so the
pressure would still build ( I beleive their is pressure)
2...On a DIY system, I have yet to see a bubble counter ( which I beleive is how you
regulate how much CO2 is going to tank ) is this only for presurized systems.
3...The system I would like to build is on this link
http/www.qsl.net/w2wdx/aquaria/diyco2.html
I would use either 1 or 2 2 liter bottles for generator and am wondering if 1 would be
enough for 70 gal tank or should I use 2...also I am going the route of using a
reactor but I only have a powerhead which is not submersible ( but I dont think this
should be a problem I hope.
I would greatly appreciate any suggestions as I would like to get at this soon and dont want to do it wrong....I built my own hood with 3 30 watt Aquaplant tubes and 2 moon
lights... I enjoyed doing it and couldnt afford $400.00 the lfs wanted for theirs..
at Christmas time I am changing tubes to U type tubes to get more watts
Sorry for being so long winded thanks and hope to here from someone

 

[pseud]

I use 2 x 2 liter soda bottles in a 55 gallon tank and it's enough. I would think you'll definitely need to use two, depending on how well your diffuser works. I was using an airstone and the upturned bottle of soda bottom method (better description on link you provided), but, I just changed the airstone and am getting MUCH more MUCH smaller bubbles, so the CO2 is getting into the water better. Anyway, my point is, if I were you I'd be using 2 bottles and an upturned soda bottle bottom and see how that works out.

Unless I'm mistaken, you only have 90 watts over 70 gallon, that's about 1.2WPG, I think you should aim for at least 2wpg and preferably 3. Especially if you're adding CO2. I think you might run into some algae problems. (someone more expertise in this area will be able to advise you more thoroughly though).

 

[@ombomb]

At 1.2 WPG I don't really think there is any need for CO2 as the plants won't be trying to gorw fast enough to use it.

Personally (in a 47.5 Gallon) I use two 3 litre spring water bottles and am currently changing the mixture in one of the bottles every two days! In a tank that size, I'd really recommend saving some cash up and buying a pressurised system. It's what I plan to do (or wait till Xmas).

Also have a read through this pinned thread for some general info on CO2 systems.