dezizz
Aquarium Advice Newbie
I have a 55 gal fish only tank with damsels and clowns, some crabs and snails. It has been up and running a long time but I have a problem. Although my ammonia and nitrites are zero, my nitrates stays around 15-20 ppm, what to do? (note: I use 50/50 bulb) Also I siphon the gravel monthly with a 25% water change is this correct?