The Tankminder is made from a stainless steel, compact, 20 cm long tank level indicator. This sender works on the simple principle of twin magnets in the float activating two thresholds on a PCB board securely housed and doubly insulated inside the stainless steel tube. Designed to be fitted into the top surface of a tank with a male 1 ¼” BSP thread.
The sender simply screws into the threaded fitting (fitted by Tek Tanks) or a flange (if fitting as a retro fit) allowing for a quick and easy removal for inspecting and cleaning.
If you want to connect it to a single light panel, you can bring the signal on at approximately 9 or 16 cm from the top of the tank depending which wire you connect.

Alternatively you can use it with our 3-LED gauge. This gauge has three coloured LEDs. Green shows the tank has plenty of capacity. The yellow light will then come on indicating the level is 16cm from the top. Finally the red light will show indicating that the tank is full and will require emptying.


Supplied with a nylon flange with nitrile gasket (Ref: FL-3). Wiring diagram also included. 

The S3H Kit

Robustly made from 316 stainless steel and fitted as original equipment for over 30 years by all the major British and European boat builders, our senders still work on the simple principle of twin magnets in the float tripping a series of reed switches securely housed, and doubly insulated inside the stainless tube.

Over the years senders have been improved with advances in reed switch technology, allowing  far more switches to be fitted inside the senders, giving a better resolution required by modern digital displays.

The S3H Kit holding tank senders are surrounded by a removable 316 stainless steel cage to protect the float from the worst of the black water.  If necessary this is easily removable for cleaning.

The “Kit” comprises of a fitting flange, a 12/24 volt DC analogue gauge and a sender. The available lengths of sender are shown in the table below.

SHS-1  100mm
SHS-2  205mm
SHS-3  305mm
SHS-4  410mm
SHS-5  510mm
SHS-6  650mm
SHS-7  700mm
SHS-8  760mm

The senders are based on the S3 Series type but with an added stainless steel shroud to stop any nasties interfering with the float. The shroud can be easily removed if cleaning is necessary. The fitting thread is 1 1/4″ BSP making the sender easily removable from the tank by just unscrewing.

Gauge comes with a choice of panel light colours and full wiring instructions.

If ordered with one of our tanks then we will fit it free of charge and test for leaks.

S3H Waste Sender