Donsfish was right,meant nitrites zero. Thanks,bud
The overall turnover through the filters for the tank should be a minimum
of 5-6X for the filter styles you are using. Hard to determine what the proper flow through an internal sponge-style should be though as it's dependent on the sponge's total surface area. You should be looking at 550gph,preferably more,through all the filtration. You really don't need supplemental circulation unless you feel you need it due to "dead spots" in the tank.
You can make room for more media in the canister by eliminating the carbon.It's not a necessity,can mask water quality issues (and readings),and if not changed on a tight schedule lead to other issues.The only important function is to remove foreign
compounds from water...if you are the careful sort about what's allowed near the tank (no aerosol sprays for example) you should never need it.
also could any one tell me how much my gravel will be contributing to the water quality and if at this time with the water being as is, is it best to remove it .
It's not the gravel,but what get's trapped in the gravel,that affects water quality. Most of us have a substrate that consists of gravel so it's just a matter of maintenance on it...no need to remove it. It actually serves a purpose in the filtration of the tank as it houses quite a bit of beneficial bacteria on its surfaces,so just out-and-out removing it may affect the water quality in a negative way. Better to balance out water quality with it in place.