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preeble

Calcium Crystals?

preeble
15 years ago

My pool completed late last summer with a Hydrazzo finish. I found myself having to add a significant amount of acid to keep my PH in check until I closed the pool in the fall.

When I opened my pool up this spring, my PH was off the charts and I had white crystals growing on the surface of the pool walls and floor. I have no idea what these crystals are, but I believe they are calcium (the crystals dry into a white power when I take them out of the pool). I added acid to the pool to get my PH in-check (and it has been relatively stable since) and took my pool water to be checked, expecting the calcium levels to be high, but my calcium was only at 250... All of my other readings were in range as well, except for my alkalinity, which was low and I subsequently added chemicals to bring it up.

I was able to brush and vacuum off most of the crystals, but I do have some remaining that will not brush off - I suspect I will need to sand them off.

Has this happened to anyone else? Can these crystals really be calcium that fell out of solution even if my calcium level is 250? Could this be a by-product of the Hydrazzo finish?

I contacted my PB and am waiting to hear back.

Thx.

Comments (7)

  • barco
    15 years ago

    Do you have a Salt Water Chlorine generator? Sounds like Salt crystals to me.

  • preeble
    Original Author
    15 years ago

    I do have a SWG - why wouldn't the salt crystals fall back into solution? I have since added more salt to the pool and it quickly dissolved.

    What is the best way to get these off without draining the pool? Sandpaper?

    Thanks.

  • barco
    15 years ago

    They will...thats why they sounded like salt when you described them. However, if you get a bunch of water on top of a cover or something and then the hot sand bakes off the water, you end up with a film of salt crystals.

    What I used to do is take the hose and wash down the sides of the pool or whereever the salt crystalizes...saves on having to go and rebuy salt if your removing them.

    Not sure how you say it is crystalling on the floor though.

    I do know they don't readily rehydrate as does the fresh salt. I suspect thats because they have a lot of impurties in the crystal matrix. Many times the salt will be more of a light brown as opposed to the nice pretty pure bleached salt you get in the bag. But if they sit in there long enough with aggitation, they should go back into solution....but not instantly like you would expect with a wafer thin piece of salt.

  • ventura43
    15 years ago

    I had the same thing when I uncovered this spring. The link below outlines some hints I got from another forum. In the discussion I talk about "scale", but what I had sounds like what you are describing....little individual crystals (almost looked round) attached to the sides and bottom. My pool was new last year and pH control was constant. I didn't check while it was covered this winter but it was sky high upon opening. My CH was high as well but I was told the scale was more from the pH than the CH.

    I opted for the method talked about in the linked thread. I dropped TA and pH and brushed like crazy for about 2 weeks. It didn't all come off. I was also able to scrape alot off the sides with a plastic scraper but couldn't reach the bottom.

    This weekend was the first time we got temps above 80 so in I went. The floor is a little rough, but nothing like what was on the walls. Now that I have pH in normal range I'm having a hard time scraping off what I didn't reach before.

    Once all the grandkids visit in the next month I'll probably do the Magic Jack stain remover treatment. If that doesn't work we may acid wash at the end of the season.

    Good luck. I know now to check pH all winter long!

    Here is a link that might be useful: Topic on troublefreepools.com

  • preeble
    Original Author
    15 years ago

    Thanks - that was great info. I suppose I will go down the same route as you for now - lower the ph and brush a lot with some sort of mixed brush.

    Like you, I was unaware that I needed to check my pool chemistry in the winter (although it makes sense to do so). My filter and SWG are turned off in the winter, but since my pool was so new, I should have known that I would need to periodically lower the PH.

    In any case, I hope that over time I can get the bumps out because I really liked the smooth surface of my pool.

  • bamodeo
    12 years ago

    I've got some great pictures of this phenomenon. How do I post them ?

  • radmjk
    9 years ago

    How did you ultimately correct this issue because i find myself with the same problem? Hydrazzo finish with tiny rough white crystals on much of the floor and wall surfaces.

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