For the 3g. betta tank, the water always tests 0 for nitrites and nitrates (ammonia test kit is at a friend's)---I was just trying to keep it extremely clean. I will cut back on his feeding although I wonder if doing it right now will weaken his system. I just dosed BettaFix so this should help. Regarding the filtration system for the 30g. I don't overfeed and in fact was going to buy a 2nd Marineland to ensure adequate filtration. However, I was advised by several people to NOT do that because it would keep the water too clean seeing as there are plants in the tank. The filter is rated up to 50g. and albeit that's not huge, neither is my bioload. I believe I'm over-cleaning the tank. Thank you for helping me. There might be a tad bit of confusion here: the betta tank (3g.) tests 0 for nitrItes and nitrAtes which is why I'm confused regarding why he appears to be sick. I just did a 100% wc prior to dosing the medication and there was no gunk coming out from the sand. That tank is clean. The 30g. planted tank is the one having cloudy water and high nitrate issues, not the 3g.