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..
Ryan