I will make a tank water sensor on my water tank in our caravan. (60l)
I use 5v on 5 rod, i put this i diffrent messurment in the tank.
Like this: LED Water Level indicator PCB Tutorial - YouTube
But I wil use stanles steel rod.
The sensor going to be on 24/7 when the power of caravan is on ofc.
Wil this make problem of oxidation created by the phenomenon of electrolysis ?
Or wil this work and i can drink it xD 
That doesn't sound good. Use a capacitive sensor, the probe can be insulated with a plastic or other safe insulating material, and there is no possibility of contamination if you use an appropriate one, since there is no metal contacting the liquid, and no DC current.
TL;DW
PaulRB:
https://www.youtube.com/watch?v=n9GB0nfwG8s&feature=youtu.be
Yes is this link i post
aarg:
That doesn't sound good. Use a capacitive sensor, the probe can be insulated with a plastic or other safe insulating material, and there is no possibility of contamination if you use an appropriate one, since there is no metal contacting the liquid, and no DC current.
Never work with camacitive sensor.
How can I use this in my work?
And what type you think I can use?
Knutarn:
Never work with capacitive sensor.How can I use this in my work?
And what type you think I can use?
Knutarn:
Yes is this link i post
No, you pasted a web address into your post. I made it a link.
There are hundreds of type of "stainless steel". Some may be ok and other not so good. Stainless steel is an alloy of iron and various other metals. Some will eventually dissolve out of the stainless steel.
Best to buy a short length of platinum wire on Ebay and use it in the water.
Paul
Hey! Look they are very expensive wire 
need 50-60cm of this
Or can i put it on the rod? 1cm of it. And use iso wire from top to botton and put 1cm of plat on the edghe
This rod i think abaout: STAINLESS STEEL(304)ROUND BAR/ROD 3,4,5,6,7,8,10,12mm diameter (in many Lengths) | eBay
If it not work safe.
What about this? 5 of this on the tank?
No, that includes all you personal browsing information.
Delete (don't include) the question mark and everything behind it.
This is enough.
Or a link to it.
Leo..
Wawa:
No, that includes all you personal browsing information.Delete (don't include) the question mark and everything behind it.
This is enough.
Or a link to it.
Leo..
Ho thx xD
Paul_KD7HB:
Best to buy a short length of platinum wire on Ebay and use it in the water.Paul
That's only one electrode. The tank is the other one, and platinum tanks are very expensive. Unless you are talking about two wires...
What about using a time of flight sensor (ToF)? They are commonly used to measure water height among other things and do not have direct contact with the water.
A little electrolysis will not make you sick, but I suggest to use food-grade materials or don't do it.
Stainless steel can be so many things as Paul_KD7HB already explained. If you buy Platinum or Titanium it might be mixed with other metals and perhaps it is only a thin coating.
The non-contact level sensors are perfect 
Once again: Food-grade or don't do it.
Koepel:
Once again: Food-grade or don't do it.
+1
Koepel:
A little electrolysis will not make you sick, but I suggest to use food-grade materials or don't do it.Stainless steel can be so many things as Paul_KD7HB already explained. If you buy Platinum or Titanium it might be mixed with other metals and perhaps it is only a thin coating.
The non-contact level sensors are perfect
Once again: Food-grade or don't do it.
So this shuld work: https://www.ebay.com/itm/5-12V-Non-Contact-Liquid-Level-Sensor-Waterproof-Water-Level-Detector-IP65-IP67/313042863663
put five of this on the tank