Is your bio wheel filter,also a mechanical filter???That is one that has a water reservoir built in and the water passes through some sort of a filter pad. If so,then what I would do is remove the lift tubes from the UGF (under gravel filter).But keep the powerhead running for water circulation.Then just use the powerfilter as your main filteration,and totally unplug the UGF.You also NEED a substrate vaccume to clean the CC.Ultimatly,your BEST BET is to get rid of the UGF and CC and go with a DSB...