We plan to camp at Fort Pickens in Florida and there is no full hook ups. The holding tank is like 20 gallons for black and gray, so total of 40 gallons. Its too small for a family of five to camp thr...
Anyway, it had a small red indicator that would rise as level came up inside tote. Part of the vent...supposedly it would fully block vent and stop flow course you would still have a drain line full.
But I would watch for that red indicator to start moving .....kinda like a line bobber when fishing .....and then I would close drain valve.
Never overflowed or made a mess BUT I had one of them waste totes ONCE (got rid of it)