Well there are a couple negatives about this setup.... I'll name those first.
The ballast below (Dual PFO HQI Ballast) put off A LOT of heat. So unless the output of filters is closed they will drain slightly and the rest will be evaporated drying out the cartridges. Not good. So I put a JG valve on my output so just before I turn the water off at the source, I shut the valve and then turn the water off. This keeps the filters from draining doesn't allow evap hence keeping them stable and wet.
The other downside is that when I go to change the filters (not that often), but be careful not to drip water on the 800watts of electricity below....
I used a Copper Adapter to go from a faucet thread to a standard thread, then a copper T and then one end has a faucet coming off and the other another adapter to go from standard thread to faucet thread for the washer. This is where I turn the water on an off.
As far as the Kent Float Valve, It has been in there for 1 year (with fans blowing right across it not by design, just by chance) and I've NEVER had a problem with salt creep. Remember when you turn your pumps off the water in the sump will rise and cover the float valve hence cleaning it off...
Hope this Helps..