i need someone to hold my hand for this CO2 decision ;)

You're on the borderline of no light setup. Adding CO2 can and will help, but increaseing the light is also a good idea too. at least 2.0 wpg

DIY CO2 GUIDE: http://www.aquariacentral.com/forums/showthread.php?t=68834

When adding CO2 through DIY you won't have to worry to much about the pH flux and CO2 levels. They won't harm the fish. Case in point, people including me run CO2 pressurized 24/7 without any problems. DIY CO2 won't get you to dramatic levels that will harm the fish. As for the pH flux, no need to worry about that since it's the fluxuations aren't major, and again I've had no problems. O2 levels again, no worries with DIY. If you are really concerned an airstone at night for a few hours will be fine, but not necessary.

Definately add CO2.

-John N.

kyle i feel for you. been there and finally held my breath and made a decision and hoped for the best.

understand i am basically a lazy guy. if i can avoid creating too much extra work for myself that is the route i choose. and, if i opt to do something i want to do it well.

Given that a few thoughts.

first, you are the only one that knows what "overstocked" in your tank means. Understand that the plants will provide oxygen to the tank during "lighted" periods. there will obviously be competition for oxygen during darkness. Your fish will always lose the battle for oxygen in a tank when pitted against the "lower" life forms.

Rarely, however, are you going to see the tank so imbalanced that fish deaths occur.

When you see fish gasping at the top of a tank in a planted, Co2 environment it is usually too much Co2. It is not typically the lack of oxygen. The pH problem that the Co2 creates may also be at issue given the species of fish you keep.

i went with pressurized, pH probe, pH monitor and regulator. as well as reactor chamber and powerhead. the system could handle a tank 3-4 times the size it is in. "overkill" is one of my operative words.

it boils down to what the heck you want out of a tank. there are compromises to be made when going with a Co2 system. plants v. fish is the compromise. too many, or the wrong type of fish will mean all you have is a giant salad bar. your fish will enjoy it. your plants will be ravaged.

i would not go back and take the Co2 out of the tank (did that when i first installed it--for all the right reasons, me). i am having nothing but fun learning the higher light, Co2 tank. i made the comment today, at a different board, that the difference in low tech planted tanks (which i kept for many years very happily) is that the amount of growth and types of plants seem to be the biggest differences between the two approaches to planted tanks. and, as someone so aptly pointed out, to amplify the comment--things can go wrong much faster in a higher tech tank. problems from nutrient imbalances can show up overnight in a higher tech tank. the same problem in a low tech tank can take weeks or months to show up.

if you are happy with the plants now--why change? If you are unhappy, and you have an overstocked tank. or a tank that is stocked in such a way to be incompatible with a higher tech tank, then you have to make a decision involving far more than pressurized Co2.

i have no experience with the hagen Co2 system. everyone that knows me said very simply "you'll outgrow it very quickly'. and they were probably right. but, the tank i went higher tech on was a 40 gallon breeder which was swapped out quickly for a 75 that was not planted at all.

good luck. have fun.

kyle,
help me out. i am totally unfamiliar with this board to be honest. if i click on your name i get your "member page". the page i see has nothing about your tank(s). is there another area that has "user" not "member" pages?

you are a bit overstocked -- lol. are you going to have a contentious oxygen relationship--doubt it very seriously.

sounds like you have packed it full of plants as is--why Co2? you will also need to upgrade lighting.

are you after the ability to "scape" the tank?