The holding tank on Santosha is a rather small 11 gallons. It is Stainless Steel so installing a monitor is somewhat difficult. Although pricey the Gobius4 system seemed like a reasonable solution. The Gobius is manufactured by FM Marine and sold through AB Marine in the US. It mounts on the outside of the tank and uses vibration and accelerometers to determine the waste level. The system is pretty easy to install. I took power from the light over the sink. The directions were a little lacking so I needed to use an ohm meter to determine which wire was + and -. The wiring is not marine grade tinned copper so I coated the bare copper with dielectric grease prior to crimping lugs on. The manufacturer recommends using Vaseline on all connections so I figured dielectric grease would work fine and I used it on all connections. Note that even the control wiring to the panel has bare copper connections.
Calibration is simple but requires the tank to be empty. While it is turned on it runs every 5 min to determine the tank level but you can turn it off easily when not needed. Each time you turn it on it will run and give you the current level. It only shows empty, 1/4, 1/2 and 3/4 tank levels. The paperwork does say something about hooking an analog gage to an extra output. I haven’t explored that yet but it would be nice to have a more accurate reading.
I cut a slot in the fiberglass for the cable and mounted the control pad above the sink making sure it would clear the door over the sink.
I checked the readings by adding one gallon of water at a time. I did get one erroneous reading and will monitor that to see if it happens again. As it is the 1/4 level it is not too important. The readings are as follows for this 11 gal tank:
Empty - 0
1 gal - 1/4
2 gal - 0
3 gal - 1/4
4 gal - 1/4
5 gal - 1/2
6 gal - 1/2
7 gal - 1/2
8 gal - 3/4
I stopped at 3/4 as that is the max reading anyway. Reading seemed reasonable except for 1 gal. Note the Jabsco pump takes 24 pumps per gallon.