The "button" type tank sensors the RV manufacturers use are flippin' hopeless yet they continue to install them. TP + p**p gets coated on the tank walls and stays there and short circuits the sensors. Flushing may or may not clean the tank walls enough and depends somewhat on the shape of a tank (3rd pic for ex.) and where the flushing device is located (in-tank, back flush elbow or in-tank wand). There are many different tank configurations and different outlet pipe locations and owners experiences can vary. Even if a flusher can reach the sensors, the force from the spray is likely insufficient to clean the tank walls enough. Some owners have found that the sensors have been installed at incorrect elevations, causing incorrect readings.
Horst Miracle probes (2nd pic) may or may not help and depends on the tank's shape and if they can get flushed well enough. We installed them on a previous TT and they worked great. Installed them in our current TT and they don't work at all. You can see how gunk could get trapped inside the plastic tube and would be difficult to flush clean.
Our owners manual says to use Liquid Drano to clean the tanks (doesn't attack metal or plastic). Works great to clean the tank back to factory new condition, however it doesn't take very long before the false readings return. Some use other methods & products to clean their tanks, but will still end up with false readings. We have a built-in flusher and it cleans the tank bottom below the toilet but not the probes.
I installed a shutoff valve behind the toilet and can peer into the tank to see how full it is. However, tanks are quite shallow compared to width and length and solids drop drop into the tank and build up below the toilet and you can't see what the rest of the tank is doing (solids don't soften and flow sideways in the tank). I find the "peer down the toilet" method using a flashlight works good enough.
The problem with a Seelevel setup, Horst Miracle probes or checking existing sensor elev. is that if you have an enclosed underbelly, removing and re-installing it is a major job.
Most simply learn to figure out fast a black tank fills up without using the sensors or looking into the tank. We've been able to get up to about 6-7 days for two of us. Putting in 3-5 gallons before using the tank and not scrimping on water when flushing helps quite a bit to make it last longer.
Horst Miracle probes (2nd pic) may or may not help and depends on the tank's shape and if they can get flushed well enough. We installed them on a previous TT and they worked great. Installed them in our current TT and they don't work at all. You can see how gunk could get trapped inside the plastic tube and would be difficult to flush clean.
Our owners manual says to use Liquid Drano to clean the tanks (doesn't attack metal or plastic). Works great to clean the tank back to factory new condition, however it doesn't take very long before the false readings return. Some use other methods & products to clean their tanks, but will still end up with false readings. We have a built-in flusher and it cleans the tank bottom below the toilet but not the probes.
I installed a shutoff valve behind the toilet and can peer into the tank to see how full it is. However, tanks are quite shallow compared to width and length and solids drop drop into the tank and build up below the toilet and you can't see what the rest of the tank is doing (solids don't soften and flow sideways in the tank). I find the "peer down the toilet" method using a flashlight works good enough.
The problem with a Seelevel setup, Horst Miracle probes or checking existing sensor elev. is that if you have an enclosed underbelly, removing and re-installing it is a major job.
Most simply learn to figure out fast a black tank fills up without using the sensors or looking into the tank. We've been able to get up to about 6-7 days for two of us. Putting in 3-5 gallons before using the tank and not scrimping on water when flushing helps quite a bit to make it last longer.
