Im trying to limit the number of holes drilled into norwesco tanks. Im adding return from pump and sediment filter, float valve, dos awc, heater, temp probe, optical sensors. Ive read about the uniseal and pvc with a cap. I think i would rather go through the lid instead of the tank. Any ideas ? Pics? Could I eliminate the float valve and depend on the apex and two solenoids and maybe a flo lok sensor for protection? I did some maintenance recently and found discoloration on all the float valves. What are the blue center pieces for on the caps of the tanks?