Thanks to your help I have now an idea of the best regulators... what about diffusers or/and reactors? What would you suggest for a 75g planted tank? There is too much out there that I am completely lost!

Thanks.

Fab.

Don't forget the Azoo regulator if you're tring to be budget conscious. I have used one for awhile without any problems. The needle valve is not the best but that can always be upgraded later.

Drs Foster and Smith carry them $95.00

CO2 Pressure Regulator w/Solenoid

For 10 gallon tanks almost any diffuser/reactor will work fine. For 55 gallon tanks, perhaps an external DIY reactor would work best. But, with the size tank you have I think the options are more limited. You need a way that gets a lot of CO2 into the water quickly, and does it so the CO2 enriched water is well distributed around the tank.

Tom likes injecting CO2 with venturis in high flow water lines for bigger tanks. Another option is in-tank CO2 mist systems, that use the water circulating pumps or powerheads to disperse lots of CO2 quickly. I suggest spending a lot of time researching the various posts here describing those kinds of systems, and picking one that suits your budget and DIY abilities.

Thank you VaughnH, I am actually looking around and I found the following interesting solution:

http://www.aquaticplantcentral.com/f...2-reactor.html

What do you think about?

I'm not a good source of "wisdom" about anything to do with big tanks. The last big tank I had, a 120 gallon one, was about 5 years ago, and it only used DIY CO2. Others here are much better equipped to answer your question.

What do you mean with "DIY" ? I am sorry, I am VERY newbie here!

Thanks!

fablau,

DIY, as in "Do It Yourself" CO2. That is a technique for adding CO2 to an aquarium using a mixture of yeast, sugar, and water (usually via a sealed 2 liter bottle).

The yeast eats the sugar in the water and puts off CO2 as a byproduct. That CO2 can then be trapped in the bottle and (sent through an aquarium airline) to the aquarium. It is an alternative to a pressurized system, but it is also a lot more work, and it is much harder to keep CO2 levels stable. You often need to have several bottles of yeast/sugar that are rotated in and out of use at different times in order to get a relatively steady flow of CO2 to the tank. DIY CO2 also becomes harder as aquariums get larger, because the volume of CO2 the tank needs is increased.

I have seen a few people that have used DIY CO2 for their larger tanks (75-100gal) and used a 3-5 gallon glass carboy (or other suitable container) as their reaction chamber instead of the 2 liter bottle and have had good success. A quick Google search would most likely provide you with all the info you need if you were interested in trying this.

I tried using a 3 gallon carboy (and having the output send the CO2 bubbles to the intake of my canister filter) with my 75 gallon tank. It worked well to provide the quantity of CO2 I needed during the day, but the overall production of CO2 seemed to vary widely with small variations in the temperature of the water in the carboy (the carboy water temperature fluctuated with the air temperature of the house).

I have heard of people putting their 2 liter bottles in a bucket of water or in a small extra fish tank and having an aquarium heater (careful about putting a heater in any sort of a plastic container though, they get hot) in there to keep the CO2 mixture the same temp at all times. I never tried that as I was already having a hard time fitting the 3 gallon carboy in my tank stand, haha.

The nice thing about the carboy, was that I could make one big mixture of water, sugar, and yeast and get good production out of it for a few months (with only minor shaking of the carboy occasionally to keep the mixture going, and/or small additions of extra yeast/sugar every so often) instead of needing to rotate in and out lots of smaller bottles on a regular basis.

Have a good one, Jeremy

Thank you Jeremy for your explanation, that's very interesting. I will find out more considering the fact that I have a big sump under my aquarium that probably can accommodate easily an inline reactor or something similar...

Thank you again.