Ok, some of you seasoned fish people out there may be laughing at this question, but I am stupefied. I have a 30gal tank with 1 big (4inch) pleco, 1 med catfish, several ghost shrimp, about 20 newborn mollies and 4 yound adult mollies, and numeous tiny snails. I do 25% waterchanges about twice a month, but the water is always green!!! I use waterconditioners to prepare tap water, I've also used bottled water, but the quarium looks yellowish-green. There is no slime or anything, but the water has a tinge. I check nitrite, nitrate, ph, and ammonia levels all the time and they are usually right on target. Is the water supposed to look like this? Oh, I have only plastic plants in the tank, no live ones. Please advise. thanks ???