Removing Kalk build up from a Salinity probe?

[Sacohen]

As the subject says I need to remove Kalk build up from a Salinity probe?

My probe is in my sump where my ATO water (mixed with Kalkwasser) goes into also.

I have a lot of calcium build up on the probe and it is effecting the reading of the probe.

I have to re-calibrate it about once a week.

When I re-calibrate it every thing is fine (about 36-37ppt) and then slowly over the week it drops. It was at 28ppt yesterday before I re-calibrated the probe.

When I double check the salinity with a hydrometer is reads about 1.026-1.027 which is where I like to keep it.

The strange thing is that I just don't understand why it would read fine after calibration and then drift. If it is because it is covered in calcium deposits it should be off all the time.

The pH and temp read fine and they are covered too.

Thanks

[BHD]

Drop it in Vinegar for a few hours, everything will be gone.

[jda]

Muratic Acid will work too. Dilute it and don't get any on you or breathe it. Very effective, safe for your tank and cheap.

[Sacohen]

Thanks. Someone said Hydrochloric Acid, but as I look for it, it is coming up with Muriatic Acid, so I guess they are similar.

[jda]

Same thing. You can get either at Home Depot, Lowes or most any hardware store for pretty cheap... like 2 gallon pack for like $8, or so.

[Sacohen]

I got some information from the supplier and this is what they had to say...

0.1 mol/L dilute hydrochloric acid (make up: 9 ml of hydrochloric acid diluted with water to 1000 ml) for 24 hours and washed with pure water, and then use electrode immersion fluid immerses 24 hours
If the passivation is serious, also can be soaked in 4% HF (HF) solution (3 ~ 5) s, washed with water, then soak in the electrode soaking liquid of 24 h

It's a bit broken English, but it makes sense. The thing I'm not sure of is what "electrode immersion fluid" is.

Maybe someone can help me out with that.

Thanks again everyone.

[Timber77]

after you clean it, put the probe as far away from you kalk drip as you can. Salinity probes are way to high maintaince to begin with.