Ok, well I had a salt tank before and I had what is called an eco system where the lights ran 24/7 and calurpa grew and kept the nitrates down.Now on my fresh watewr tank 250 gallon with a 10 inch puffer that no one can figure out what he is and a 12 inch shovel nose catfish, an 8 inch alligator gar, 2 common plecos one is 5 inches the other is 10 inches and a 10 inch black ghost. Feed krill every other day, about 15 pieces, feeder goldfish 2 times a week and 6 algea wafers per week. I have reduced the gravel from 3 inches deep to just a thin layer. Even when I just had the puffer alone, nitrates got to be a problem. Nitrates now are between 30 and 40 on the A.P test kit. So... what I would like to do is have a refugium/eco system and grow plants in it and I know"without the protein skimmer". Oh and I do 50% water changes about every 2 to 3 weeks, more often 3 week intervals. I have 6 tanks and this is the only one with problems like this. I dont mind paying good money for a refugium/eco system. The reason why I want to DYI is so I can get the practice on buildinig my own aquarium soon. A big one. So, I hope this gives enough info on my situation. Thanks for your help, it's appreciated. If anyone here knows Wes @ rare fish, he knows what the eco system is pretty much. So I hope I can find the schematics because it needs to be all in one type of set up. Holy CRAP I am rambling on here.