CALCIUM Stain on Tile


Well-known member
Jun 19, 2007
Spring, Texas

we started up our pool back in September and thanks to all the help from this site, I thought I knew what to do to avoid any issues. I keep the PH under control with acid etc...

Well in January, we had a few small issues that I had to call my PB to come out and fix, one being the autofill had broken. When fixing it, he told me he was re adjusting the water level because it was a little high. About 2 days after this, I notced the calcium stain all the way around the pool tile and gunite boulders that go into the water line. AHHHH! :hammer:

I brushed the pool religiously, including the tile prior to this, so I was dissapointed to see these stains. So, I first tried a pumus help, then I tried 4 to 1 I went 50/50 acid...still no off to the pool store to find something that would get this crud off. I found scale away....guaranteed to work. Guess what, it doesn't, at least not for me.

So, I have read about glass beads and I really do not want to do that. Am I stuck with this stain? WHat can I do? I have this beautiful pool, but it is a little emabarrasing to have this stain only 9 months after filling it up.

This is a salt pool and my most recent test results are:

FC - 5.5
CC - 0
TC - 5.5
pH - 7.5
T/A - 90
CH - 280
CYA - 40

Pool Temp - 87

Any help or advice would be appreciated.


LifeTime Supporter
Nov 25, 2007
Escondido, CA (near San Diego)
Your CH does not seem that terribly high (has the pH gotten too high?), but I will tell you what my PB told me:

"Auto-fills will create a line around the pool". The reason is that the auto-fills keep the water at EXACTLY the same level as it evaporates. Everybody else walks out with a hose or turns the valve a few times a week, resulting in the water level varying by about an inch. This spreads out the deposits.

Take an inch of deposits that you won't see (much) and put them all together at a single line and you'll see them distinctly.

He recommended that if this was a problem to start low and slowly raise the float over a few years, this changing the level (distributing the deposits) and hiding the lines that do form under the surface of the water. I'm afraid that I'll get loads of smaller lines.....

Will the pool chemistry (and the CH balance it wants to achieve) slowly decreaste the band if under-water, low enough CH, and low enough (not high) pH? I don't know.

I had a valve installed in my auto-fill so I can use it as manual if desired. I can leave it off and turn it on to fill -- it will turn itself off when full and I don't need to worry about forgetting to turn it off and overflowing. Let's see how this works.



If you have has calcium scaling I suspect that you have had some high pH spikes. This could be directly attrubuted to your low CYA. Get it up to about 70 ppm and you might find your ph becomes a bit more stable.
This post explains the why of this:
As far as the scaling goes. If muriatic acid won't take it off nothing will. I have found a mixture of tile soap (available in gallons from most DECENT pool supply stores) and muriatic acid, along with a lot of elbow grease and a pumice block is often the only cure.
Are you sure it is scale and not a metal stain?