Are My Tanks Really Empty?

[DallasSteve]

My gray water tank is filling up much faster in September. During the summer I could go 2 days between emptying the tanks. Now in September I have to empty the tanks every day. I just emptied the tanks and I looked at the meter on the wall. It says the black tank is 2/3 full and the gray tank is 1/3 full. Are those accurate? If they really are not empty why would that happen? My hose connection is made of clear plastic so I can watch the water come out. When I dumped the black tank a lot of brown water with some toilet paper flushed out. It seemed like about the normal amount to me. When I dumped the gray tank even more water rushed out under a lot of pressure for what seemed like a long time to me. I didn't time it, but my guess is about 10 seconds, then it slowed and emptied for another 5 or 10 seconds. Could there really still be another 1/3 or 1/2 a tank of gray water (and black water) in the holding tanks or is the problem that we are wasting more water and we need to reduce our water usage?

Edit: Last night, after only 12 hours since the last dump, the gray tank was so full there was an inch of water in the shower and the wall meter said it was full. Also, the motorhome is only 6 months old.

[kellem]

Tank gauges work sometimes and sometimes they don't, somewhat useless.

Can't imagine filling a grey tank in 12 hours unless large family all taking showers.

You may need to reinvent conservation here as the wife and I can go 4-5 days without dumping a tank.

[bukhrn]

1. These gages are notoriously WRONG, when flow stops completely, the tank is empty, Black or grey, (unless you have a serious blockage.)
2. It depends on tank outlet location, my outlet is at the rear corner of the tanks, so if you are setting nose down, you are probably not getting a complete dump.
Do you have a leak, in a faucet, kitchen, bathroom sink, shower? other than that, I have no idea how you have a full grey tank in 12 hours, UNLESS your DW is dumping water and not telling you, is she taking LONG showers.
I've never heard of tanks filling so quickly, we can usually go 5-7 days, but then we use a lot of paper products, so we generally do dishes once a day.

[HappyKayakers]

Not sure what size tanks you have but 10 seconds isn't long. I had an issue with a previous 5er where the tank cutout got pushed in front of the drain pipe and restricted outflow. That may be your situation here.
For the black tank - do you let it get full before dumping? I wait until the toilet burps before dumping. That allows plenty of water volume to help flush stuff out. The sensors will rarely be accurate after the first few uses.