slotsavegas it usually takes 10 minutes or more before the monitor panel reads full.
hmmm I have a flush system(s) in my last three rvs I have not experienced a leak or backwards fixture or valve or prob?!?! and I have always used it to backfill and release at least a few times then open and let it run a while.
but I have experienced failure and or miss readings on EVERY tank gauge set in EVERY rv/trailer/camper / boat etc. I have ever had!!! Those are the item of distrust and dissention!!!!
besides I think it is not nec. to fill a 40 gal tank to 30 gals a "few" times to flush it good, depending on water pressure I will let it spray and fill for about 2-3 mins each a couple times then leave drain valve open and go to toilet open flush valve with foot and flashlight look into and see if any solids left in immediate vicinity, common sense and gravity dictate that pyramid directly below toilet valve means another flush, then watch the clear connector till it runs clean. Oh yeah and it helps to use the level-up hydraulic jacks to raise the left side about a foot higher than right side.