White calcium deposits on the waterline of pool.

[moore887]

This looks like something the dentist should scrape away! I wonder is a metal scraper the only way to deal with something like that. What would cause a build up of something like that in the first place?

 

[IceShadow]

That looks like efflorescence. Basically calcium salts that are being dissolved by water wicking up behind the tile and out the grout. (Someone correct me if wrong.) Best way to prevent it is to prevent water from getting behind the tile.

 

[JoyfulNoise]

It’s more than likely coming from the coping above and the soil below any decking adjacent to the pool wall bond beam. Depending on how the coping set in place, there is sometimes a polyurethane caulk (like a mastic joint) applied between the bottom of the coping and the top of the pool tile. Sometimes a builder simply uses a mortar bed and jointing trowel to point the mortar between the two. If there’s is just a mortar joint there, then any moisture can wick through and form an efflorescence there.

 

[moore887]

Thanks Matt and Dustin. It is a salt pool. At first I thought it was because of a high CH in the pool but that's not the case (or has ever been). The salt level has however been high (I've seen it twice on Hayward T-series when the low salt warning on a failed cell is treated by adding more salt instead of tested).

A google search on efflorescence doesn't give me much to go on in terms of an effective way to remove it. Dispite having three different pool service companies looking after this pool since it's construction six years ago, the problem has never been addressed or brought to the attention of the home owner.

Do you think it's safe to just chip away at it or could there be a chemical that would disolve it?

 

[ajw22]

Do you think it's safe to just chip away at it or could there be a chemical that would disolve it?

Diluted MA mix of 4 parts water to 1 part acid.

Or you can try scraping it with a grout saw.

QEP Handheld Grout Saw with 2 Blades for Cleaning, Stripping and Removing Grout 10012Q - The Home Depot

The QEP Professional Carbide Handheld Grout Saw with Dual Replaceable Blades is ideal for stripping, cleaning and removing old grout. It has 1-carbide grit-edge and 1-steel tooth blade. It uses 2-blades

www.homedepot.com

White Residue on Tiles

Hi, My pool was recently completed and I'm just making sure that there aren't any issues to bring up to the PB that I haven't yet. One minor thing that's been bothering me a little is that there's a section of tile by my spa's spillway where there's a white substance that's dried and stuck on...

www.troublefreepool.com

 

[JoyfulNoise]

Efflorescence can be a mixture of many things - salt, silicates, carbonates & phosphates. So there really isn’t one chemical that will work perfectly. The easiest thing to do is to mechanically scrap it away with the least abrasive method possible. I’d start with a stiff nylon or Tampico brush and then follow up with a steel bristle brush or pumice stone. Try to knock off as much of it as you can to get down to the grout. Then you have a choice - you can either do a very light acid etch and then seal it OR you can simply leave it alone and see how quickly it returns. I would suggest that if it takes a year to return, then just plan to knock it off with some elbow grease. However, if it’s back in a week, then you have to start looking for the causes of water infiltration.