I have a 20g long(glass) with 2 500ghp pds,fluval c5 hob filter,100w heater,37 lbs of lr,20lbs of sand,2x24w t5s,no skimmer yet saving my money for a nice one i figured theres no point in buying a crappy one, The tank is 3mo old,I had a nitrate problem.I was told to remove the sponge first then...