Calcium Scaling?

[abrink]

I have a spa that overflows a rock wall ledge into the pool. In the mortar between the rocks I am noticing what appears to be white calcium scaling? Scrubbing with stainless brush removes a small bit. (very hard scrubbing.)

Whats the best way to remove/prevent this?

Current Test Results:
PH=7.8 (Added 12 oz of acid to drop this to 7.5ish)
TC=5.5
CC=0
CH=300
TA=80
CYA=40

 

[jblizzle]

If it shows up where water is spilling over ... there is really nothing you can do to stop it. As the area gets wet and then the water evaporates, it leaves the minerals behind. You can try a diluted solution of muriatic acid and more scrubbing (wear appropriate safety gear ... gloves, goggles, etc).

 

[RobbieH]

Are you sure it's not salt?

 

[abrink]

Not completely sure. Its somewhat slimy/glossy looking -- doesn't appear to be left over salt residue.

 

[jblizzle]

If it is slimy, it is not calcium scale.

 

[Norcal Spearo]

You can find a few videos on YouTube about ways to remove pool calcium.

 

[abrink]

Maybe that's a bad description. It's not soft, it's hard but glossy looking. Reminds me of stalagmites in caves.

 

[BoDarville]

...it's hard but glossy looking. Reminds me of stalagmites in caves.

Sounds like it could be efflorescence. It is caused by soluble salts and other water-dispersed materials come to the surface of concrete and mortars. While it is an eyesore, the good news is that it is rarely a structural concern. It can be removed with old-fashioned elbow grease using tools like scrapers and steel brushes. Some muriatic acid will speed the removal up a bit, but you will still get a workout. As far as preventing it, the best bet is a masonry sealer. This will need to be applied when the surface is completely dry and the coating will require drying time above and beyond that. Plus, the coating may need to be reapplied periodically.