Brown Calcium deposits on pool floor

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jhenahan

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Sep 9, 2012
3
Hey Everyone,

I've been taking care of my pool for a couple of years now, but have been battling calcium deposits the entire time. For a brief history:

When I purchased the home (Summer 2012), I noticed that there was white calcium scale on the flagstone at water level. There was also brown stain on the plaster under the water.

I left it alone until last year (Spring 2014), when I used the Jack's magic test kit to determine that the brown stains were also calcium. I used Jack's magic #2 (Copper and Scale stuff) to remove the brown stains. Of course, this involved installing a bypass on my pool heater, and dropping the PH to something close to 6.0 for quite a long time before it all went away. Towards the end of the treatment, I noticed that I was starting to get hard brown deposits on the pool floor (which didn't have anything to start). All the brown stains from the wall were removed, but by the end of the treatment, I had a few hard brown deposits on the floor that wouldn't come off.

I called the Jack's hotline, and they told me that what probably happened is that I had small cracks in the plaster surface, but they were being filled in by the calcium scale. By the time I removed the scale, it opened up the cracks, and calcium leaked out from the plaster.

So, I have a question: Has anyone experienced this, and how did they handle it? The brown deposits have grown over the winter, and now I have quite a few. I'm not sure what was worse: The original brown stains or the new brown clumps on the pool floor. Of course, I could use another round of Jacks Magic products, but I'm worried I'll just make it worse.

For background, I believe my pool is about 7 years old (I've owned it for 3 years). I do my best to keep the chemistry in check, but the PH rises very quickly, so it can often get up to 7.8 or 8.0 before I have time to add acid and reduce. Also, I drained and filled last year after my calcium level got above 500 (after completing my Jacks magic treatment)

Pool Type: 25,000 gallons, plaster, with SWG and DE Filter
FC - 4.0
pH - 7.2
TA - 90
CH - 250
CYA - 60


Thanks in advance for your help, and sorry for the long post.
 
Calcium scaling is white, but can easily be colored by other impurities in the water that precipitate out at the same time as the calcium. The most likely possibility for brown coloring is iron. It could be that as you dissolved the calcium scale away you also put the iron that was coloring the calcium brown back into the water. The iron could then form metal stains of it's own, separate from the calcium. This theory is easy to test for, place a vitamin c tablet on one of the new brown areas and see if it has any effect. If it does, those are iron stains and can be removed with an aa treatment.

The Jack's people are normally very good, so their explanation is still the most likely. However since mine is so easy to test for, and theirs will be difficult to deal with, you might as well check out my theory before spending a lot of effort on theirs.

It would also help narrow things down if you could post a complete set of water test results.
 
Thanks Everyone. I updated my signature so you can see all my info. I didn't have a chance to test it this weekend, but will probably tomorrow. The explanation that the Jacks people gave me for the original brown stains was that it was calcium scale that just trapped regular dirt (not necessarily iron), but I'll try the vitamin C and see what happens.
 
Ok, I tried the Vitamin C pill and it seemed to soften the deposit. Nothing dramatic. No visible reaction. But I left it there for a few mins, then I started rubbing it with the pill, and some of the deposit started breaking down. It didn't come completely off, but I definitely wore it down.

Thoughts? Am I better off trying an AA treatment, or something else?

I found a link that may desrcribe my problem. The pictures show white nodules, but my original calcium stains were brown (due to contaminants), so I suppose any new calcium deposits may also be brown. http://www.poolgeniusnetwork.com/profiles/blogs/calcium-nodules-in-pools

As I looked a little closer tonight, a few of them grew in a straight line along what seems to be a microcrack, so this may make sense. Others are just random shaped clumps seemingly in the middle of nowhere.

Test results were in my original post (didn't test again tonight), and I keep the chemistry relatively stable (other than the PH like I mentioned).

Thanks again for your help.
 
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