Scale deposits on pool tiles

[cancuntom]

Our pool this morning.......This pool is located in the garden of our home in Cancun, Mexico. The water here is very hard. The pool water has been in the pool since it was finished almost 3 summers ago. In the past we used Muriatic acid and a brush to scrub the "bathtub" ring off of the pool perimeter several times a year successfully. This season we developed this thick scale that isn't phased by the Muriatic acid scrub. The only way I can remove it is with a paint scrapper and razor blade. The pool sides and bottom are covered with ceramic tiles. We've never had deposits build up on the stainless railing going into the pool in previous seasons. It took me about 3 hours to scape it clean. We use Triclor tablets, Hit OK, and chemicals to raise or lower the PH as needed and monitor the chemistry with a basic kit every week even when it's winter here. We also use a product called Cristalin Platinum which gives the water a blue hue and makes it really sparkle.

Scale deposits around entire pool at waterline as well as on underwater lights and stainless steel railing....

Closeup of scaly deposits

My readings using the Trouble Free Test Kit TF-100 this morning......
FC=3
CC=.5
TC=3.5
pH=7.8
T/A=160
CH=230
CYA=95
AIR TEMP=85ºF
WATER TEMP=84.6ºF
We cannot seem to find a way to chemically remove the scale deposits. So far the only thing that works is mechanical removal methods. To do that we will have to drain the pool and scape it down and refill. If anyone could suggest anything I could add to the pool chemistry that would resolve these deposits I would really appreciate it.
Sending you all warm Caribbean breezes and an advance thanks.
CancunTom

 

[JasonLion]

You pretty much need to remove the existing deposits by hand, but you can greatly slow down the rate at which future deposits accumulate by lowering your TA level significantly. Right now, your PH is on the high end of the normal range, and TA is too high, and that combination is encouraging calcium deposits. I would lower PH just a little, say to 7.6, and lower TA significantly, perhaps to 90, and that should help significantly slow the rate at which calcium deposits.

It isn't related to your calcium deposits, but I notice that your CYA level is getting fairly high. You need to keep an eye on that. With CYA at 95 day to day FC levels should be 7 to 10 (or around 5 with a SWG). If you are using any trichlor tablets, CYA will continue to go up and problems are likely to ensue.

 

[JesseJames]

I have had some mild scale on tile before. I sprayed it with WD40 and was then able to wipe it off with a cloth. In your case, maybe WD40 and a stiff brush might do the job or at least help a little.

 

[dmanb2b]

I have had some mild scale on tile before. I sprayed it with WD40 and was then able to wipe it off with a cloth. In your case, maybe WD40 and a stiff brush might do the job or at least help a little.

I'm not sure I'd recommend using a petroleum based product around pool water

 

[learthur]

Sand blasting with glass beads works well..... If you can find someone with the right equipment.

 

[cancuntom]

Thanks everyone...............but remember I live in Mexico not the USA...............but............they do have WD40 here, sand blasters and glass beads..............maybe in another 20 years!