Started out with about 20 gallons of SH in the tank. Did a house wash which should have dropped it to about 14, but SURPRISE I magically had 35 gallons!
Turns out the tiny little spring in the one way valve on the 12v proportioner broke and was sending water to my SH tank. I had to use it a couple times so I guess between uses it was leaking past the valve.
Use one of these in the bleach line just make sure that it is in the vertical position. It has no springs just a positive seal when flow is going backwards. This fit a 1/5 inch hose with a little force.