fresh water tank sensor

My Nuevo Es fresh water tank sensor reads full
all the time so after some research my first step is to descale the tank so I have bought 500gm food grade citrus acid powder.
I plan to add that to the tank and top up until full and leave 24 hours then flush out a number of times .
Do I need to leave taps open to allow any gas buildup to escape and if so do I also need to leave pump on for the 24 hrs??
Appreciate and advice on this.
John

I am thinking of doing the same and look forward to your report

On the Nuevo of that age (same model as mine) the gauge only reads full(ish), just over half and about a quarter. So it won't drop from full until you've taken a couple of gallons out at least, so does it still read full when it's empty (I.e. after draining tank)? Only asking in case you're expecting it to be accurate, because accurate they are not.

The gauge reads full until almost empty then moves down slightly so obviously faulty. I have had van 9 yeArs and I know about the inaccuracy of the gauge but until recently was relatively accurate in 1/4 chunks i.e. 25% then 50% etc...

Fair enough. Ours was the same, reading full until nearly empty but has returned to show roughly the 1/4 chunks without having to add anything to clean the sensors. Luckily we live in a soft water area and don't suffer with limescale when we fill up at home, obviously can't say that when filling on sites.

Obviously in my initial query I meant "do I need to leave taps open for the 24 hours but with pump off - NOT ON!!

Watching this thread with interest as my Nuevo water gauge is also unpredictable...

Langfordj1 wrote:The gauge reads full until almost empty then moves down slightly so obviously faulty. I have had van 9 yeArs and I know about the inaccuracy of the gauge but until recently was relatively accurate in 1/4 chunks i.e. 25% then 50% etc...

I'm interested to know which electrical system your van has as they each have different types of sensor.

Just returned from short stop at sandyballs. 24 hrs before going I added 500gm citric acid to fresh water tank and left to work.
At campsite 24 hrs later flushed out three times and lo and behold water sensor now working again-success!!

That's worth knowing, thanks for the feedback.

The gauge can obviously work only in 1/4 chunks, but that's good enough. You just have to remember that an indicated 1/4 full can mean anything between just 1/4 full and virtually 1/2 full.

If the water level has fallen to just below the 1/2 full stud, the gauge will read 1/4 full, even though the tank is in fact half full minus a pint or two. (Not quite literally, but you know what I mean. )

There was a heck of an argument about this on another forum, when a couple of members refused to accept the above, and insisted that the gauge should work on a continuous linear scale. They could not (or would not ) see that the gauge could only work in steps, as and when the water level reached, or fell below each of the three studs.

Just for interest.

Yes, agreed, I was watching gauge whilst filling and emptying and could see what was happening!!

Was that 500gm in a full tank of water?

Yes as I saw recommended somewhere -  I think it was 0.05%

My problem is on the waste tank, the full tank alarm goes off when it is 1/4 full.

Charie G wrote:My problem is on the waste tank, the full tank alarm goes off when it is 1/4 full.

Wire cutters!

I'm almost serious. Ours doesn't work at all but I can't be bothered to fix it. If you leave it too long so the tank is full it just backs up into the shower tray. There's nothing very nasty in there, so a quick swill round and a wipe, and the shower is clean again.

It has only happened once. It's not too difficult to get some idea of when the tank is likely to be full.