. . "However we dont know if the ops tank has any plants in it and I would only add it if I were running high light co2 and a good amount of plants. http://www.water-res.../phosphates.htmhttp://ezinearticles.com/?Phosphate-in-Swi...&id=2137181tled6448 one of the most important things when keeping discus is changing l" . .