always struggled with low nitrate 5-10 (max) unfortunately all fish died recently due to ICH. then hints of dino algae on the sand bottom, and after a nitrate test it shows 0. what do I do now? have no fish and can't introduce anyone for months. can i add pellets right into the sump which will break down and increase the nitrate? (I dont use skimmer, have a little bit alge)