[loveflying]

I decided to bite the bullet and buy a pressurized co2 system from my lfs. The trouble that I am having now is knowing how much co2 I should use for my tank. I have a 40 gallon breeder tank with t5ho lighting. I am not sure about the bulb types but I remember the bulbs being said to be for plants growth on the packaging. The tank is pretty well planted. If you are familiar with Ramanos plant packages, I used one of those. Any advice with how many bubbles I should have going through the glass diffuser I have will be much appreciated. If other information is needed please let me know.

 

[njs74]

Your best bet is to look into getting a drop checker which uses a solution of 4 dKH and Bromothymol Blue to use as an indicator. By doing so, you'll be able to determine what the relative level of co2 is that's diffused into your water. I believe the avg. target for diffused co2 is 30 ppm. Just google or do a forum search for drop checker and you'll find a wealth of info on this topic.

I'm currently going at about 2 1/2 bps for my 55 gal without gassing out my fish and obtaining good plant growth/little algae... still need to invest in a drop checker myself!

 

[Higher Thinking]

Every tank is going to be different even tanks of the same size. This is based upon on how well the CO2 is being diffused, the plant uptake, and any off gassing that is occurring due to surface agitation. Personally I feel it is safer to use a nice surface agitation (I have dual bio wheels) and just use more CO2 which is dirt cheap. The agitation insures that you are replenishing your oxygen levels which is obviously very important for your fish. The drop checker is a good idea and you can find them on the swap and shop including 4dKH solution for about 12 or so dollars. You can also get a relative idea based upon pH change. A 1.0 drop in pH is equal to ten times the CO2 concentration before the drop. However, not knowing the exact atmospheric CO2 concentration makes this an inexact science. It is typically between 2 and 3 ppm so a 1.0 drop will yield 20 to 30 ppm.

Your growth rate will always be your best indicator along with fish behavior. Fish fleeing to the surface for air is an immediate sign of too high of levels of CO2.