? Anyone found a viable alternative for their flaky Dometic Tankwatch blackwater tank level indicator (those colored lights in the cabinet next to your head)?
There’s nothing current in the list server archives other than cleaning & maint for the in-tank sensor unit (not my issue).
Has anyone swapped out their Dometic Tankwatch in-tank BW sensor for more 'solid state' options like Tech-Edge’s ‘PVC rod’ Moda sensor?  (TechEdge is also historically known as Larsen, GeckoTech, Snake River, AccuGauge, then Diamond).
I know several NT's are using Tech-Edge’s capacitive strip level sensors for their PVC domestic water tanks (2 long parallel aluminum strips that stick to the outside of the PVC water tank).  Tech-Edge’s ‘PVC rod’ sensor is for tanks like NTs keel BW tanks, it's a sealed length of PVC pipe with 2 long capacitive strips on the inside so they never touch the contents of the BW tank.  Installation requires an 3" MPS x 1” FPS PVC reducing bushing to replace the Tankwatch float unit.
Backstory: after all the years of removing and cleaning, and of course eventually replacing Dometic’s expensive in-tank TankWatch float sensor units (those 3 different length rods with float switches on the ends), my LED display in the head finally went flaky.  The only reliable LED now is red when full, with the green now staying on all the time and never either the  yellow or orange.

My taking the display apart to attempt to trouble shoot the printed circuit assembly clearly shows that it’s no longer capable of recognizing 2 of the 3 sensor switch states - so this issue has nothing to do with mucky float switches (the in-tank float sensor unit is wired to  the LED display with 6 colored wires, a pair from each float switch - there are only two states for each pair, either open or closed - not too complicated to bench test and pretty obvious that my PCA has failed).

Dometic makes an expensive updated LED display but it’s a different shape and - in their infinite marketing wisdom - did not provide an aesthetic upgrade path for early version customers who now have an entirely incompatibly shaped hole in their lovely teak-faced lav cabinets.

The only other straightforward but certainly fiddly solution I can think is to modify the TankWatch display scrapping the original PCA, retain the original rectangular case/face with its 4 LED's, then adapt it to something like a 12vdc Arduino board programmed to detect and report the level status from the 3 in-tank float switches (if they are still operating).

So before I chuck those nasty float switches overboard (when they are clean of course) in favor of something like Tech-Edge’s rod sensor unit, hopefully there's an NT here who's already invented the wheel and has some sage advise.

Regards, Kelly Britz
SANDPIPER NT37-042
Seattle / Edmonds

In most towns you can find a (usually older) guy that can fix printed circuit boards for a fraction of a $boat unit. Panco, in Victoria, fixed mine easily.

Cheers,
Paul Bulk
Crown Prince
191-31

From: Kelly Britz via Sentoa sentoa@lists.sentoa.org
Sent: Thursday, December 18, 2025 1:57 AM
To: TIMOTHY LEIGHTON via Sentoa sentoa@lists.sentoa.org
Cc: Kelly Britz kelbritz@hotmail.com
Subject: [Sentoa] ? Alternatives to a flaky Tankwatch blackwater LED display?

? Anyone found a viable alternative for their flaky Dometic Tankwatch blackwater tank level indicator (those colored lights in the cabinet next to your head)?
There’s nothing current in the list server archives other than cleaning & maint for the in-tank sensor unit (not my issue).
Has anyone swapped out their Dometic Tankwatch in-tank BW sensor for more 'solid state' options like Tech-Edge’s ‘PVC rod’ Moda sensor?  (TechEdge is also historically known as Larsen, GeckoTech, Snake River, AccuGauge, then Diamond).
I know several NT's are using Tech-Edge’s capacitive strip level sensors for their PVC domestic water tanks (2 long parallel aluminum strips that stick to the outside of the PVC water tank).  Tech-Edge’s ‘PVC rod’ sensor is for tanks like NTs keel BW tanks, it's a sealed length of PVC pipe with 2 long capacitive strips on the inside so they never touch the contents of the BW tank.  Installation requires an 3" MPS x 1” FPS PVC reducing bushing to replace the Tankwatch float unit.
Backstory: after all the years of removing and cleaning, and of course eventually replacing Dometic’s expensive in-tank TankWatch float sensor units (those 3 different length rods with float switches on the ends), my LED display in the head finally went flaky.  The only reliable LED now is red when full, with the green now staying on all the time and never either the  yellow or orange.

My taking the display apart to attempt to trouble shoot the printed circuit assembly clearly shows that it’s no longer capable of recognizing 2 of the 3 sensor switch states - so this issue has nothing to do with mucky float switches (the in-tank float sensor unit is wired to  the LED display with 6 colored wires, a pair from each float switch - there are only two states for each pair, either open or closed - not too complicated to bench test and pretty obvious that my PCA has failed).

Dometic makes an expensive updated LED display but it’s a different shape and - in their infinite marketing wisdom - did not provide an aesthetic upgrade path for early version customers who now have an entirely incompatibly shaped hole in their lovely teak-faced lav cabinets.

The only other straightforward but certainly fiddly solution I can think is to modify the TankWatch display scrapping the original PCA, retain the original rectangular case/face with its 4 LED's, then adapt it to something like a 12vdc Arduino board programmed to detect and report the level status from the 3 in-tank float switches (if they are still operating).

So before I chuck those nasty float switches overboard (when they are clean of course) in favor of something like Tech-Edge’s rod sensor unit, hopefully there's an NT here who's already invented the wheel and has some sage advise.

Regards, Kelly Britz
SANDPIPER NT37-042
Seattle / Edmonds