Originally Posted by ThatGuyWithTheFish
How do I do that? It gets to the point where the fish start breathing heavily by the end of the day, so it should be enough.
There is also the possibility that my light isn't too strong; I'm not getting much color out of some plants.
generally that has to do with BOD
biological oxygen demand.. everything requires oxidation in the tank. plants use it at night, and the hundreds of species of bacteria in your tank use to to break down decaing matter to its basic forms.
the cleaner your tank, the less oxygen it needs to be sustained in general. this is one of the reasons soo many people with high growth rates reccommend large water changes weekly. i myself perform 80% weekly. my drop checker is yellow daily, and if i put a new fish in, i promise it will die, but over time all my fish have adjusted and are spawning healthily. so there is an adjustment phase but it only takes a few days for a new fish, but i digress
the more oxygen they have the less stressful co2 is. its the reason i switched to a wet/dry filter
good surface agitation and husbandry of the tank will promote good oxygen levels and allow you to increase co2 to adequate levels. your likely not far away from where you need to be, getting it right however is the hardest part and where most hobbyists, INCLUDING myself have made countless mistakes.
color on plants is usually a stress response to more light than it can handle, or enough light that it could damage plant tissue. so more light generally brings out more color. they can't produce the stress response if they already aren't growing well enogh. I.E. enough co2?