So I received my TS-FT002 just today. 1st what I did, I disassembled it and coated all sensitive parts by nail polish, still it is for sure far from being “water / humidity” proof - I will seal also the ultrasound sensor with hot glue or rubber around sensor in combination with hot glue. For sure that’s the reason device stops working after certain period of time the device is practically open from bottom (holes for the temp. sensor, no sealing around ultrasound sensor etc.). In the tank I will also put it to some bag…naturally not covering the bottom sensors part.
In next days I need to figure out, how I will install it…but it’s snowing outside. 
What is good so far, indeed your app @Gruijter seems to be working, data is being exchanged, let’s see how this will for when I put it to the water tank because of the signal…
Disassembled
After “coating” :
