Well the problem with wheel type filters is that they get trash caught in the wheel and that causes nitrate problems unless you keep them really clean. If you have enough l.r. 1.5 to 2 lbs per gallon I'd just take off the wheel. The leather will probably take phyto and zoo and the brighter the lights the betterpc at least halides are better.
You don't have to run carbon all the time ,"some do some don't", it's just a good idea when you introduce a new invert they will release toxins into the water . They also have chemical warefare from time to time. I didn't used to run carbon except at introduction but now I run it 24/7 and find that it makes my life much easier.
hth
chris