My polys havent been eating like they normally do and yesterday I saw my gar laying on the bottom of the tank breathing really heavy so i grabbed my test kit. I hate being a fish keeper with terrible water parameters, its embarrassing but yesterday my parameters were ammonia 0 ppm, nitrite between 2 and 5 ppm and nitrate about 80 ppm. I recently had a rena filstar (made for 75 gal) and a sunsun 304b and the tanks parameters were always good. I recently moved the 304b to my growout tank and put two emporer 400s on my 150 in its place. So in a panic last night i did a 20% water change (cant do big WC because its a cold only tap beside my tank) and immediately grabbed the 304b and switched it for one of the emporer 400s. I dosed with a good amount of prime also. Tonight i tested my water again and its still reading 80 ppm nitrates and .25 ppm nitrite. Will it take my sunsun some time to grow more bacteria for the bigger bioload? Should i replace the filstar with another 304b? Im not worried about the nitrites as they are going away fine now but the nitrates I am worried about.. What can I do to keep them down? I usually do a 10% WC daily on the tank. Any advice is appreciated..