Calcium/Hard Water Buildup

[Cayman]

I was finally able to take some pictures this morning and have been wondering what this stuff is that is building up on the tile behind my waterfall. Also, how do I get rid of it?

Here are a couple of pictures. Notice in the last one that a little nipple of this stuff has formed as well.

Waterfall shut off so you can see the buildup

Here you can see the buildup as well as a little nipple that has formed as well

Thanks for the help on this one!!!

 

[waste]

Try spraying some dilute muriatic acid (~31.45%) - try a 5 : 1 water : acid for a start - if it's calcium (which it looks like) this should dissolve it. Keep an eye on your CSI balance to help prevent recurrence On the nipple you might have to use that new brush of yours and apply the acid a few times to fully dissolve it. BTW - this mixture can also be used to descale your salt cell, as long as you're mixing the acid, make enough to do the tiles and also the cell (if it ever needs it) - 1 less time you'll have to mix acid to water.

As always be safe while using acid!! Gloves, long sleeves and eye protection are a must!! Also stay out of the fumes, they'll take your breath away. Have a source of fresh water on hand, to dilute any that splashes and always add the acid to the water NOT! vice versa!

Hope you will take care of this issue in a safe manner and not have the same issue again :-D

 

[Cayman]

Thanks a million waste!!! I will give it a try and post my results w/ pictures!!!

Thanks again!!!

 

[waste]

Glad to help

I just noticed that you've put your chem #s in your sig - you're a little out of balance Use Jason's calc (in my sig) to run your numbers - you either need to lower the pH a little or raise the alk to prevent further calcium scale issues

 

[Cayman]

waste... Yes, I added some acid the other night after I took those test results. I have not checked it since though. Will be checking PH tonight though. I am also a little low on CYA but that should be taken care of now too. Just waiting for the FC to drop some more since my shock treatment!!!

 

[Cayman]

That did the trick!!! Only took me about 10 minutes to clear it all up. You could just see the mixture eating it away. Pretty cool stuff!!

Thanks again waste, you rock!!!


Before....

After....

 

[spishex]

Nice before and after!

 

[Charlie Wathen]

Found this thread and had to add some questions.

What causes this build up? I have a water line of this stuff all around my pool. Is using a Pumice stone worthwhile? I tried it on one tile and it worked to remove the calcium water line, but that was only one tile and I still have over a hundred left. I can only imagine that after doing 20 or so tiles, I would run out of elbow grease LOL.

On my pool, I have a small rock waterfall from the spa into the pool. The flat rocks also have a build up of calcium. I guess the acid method is the only way to remove it.

What causes this in the first place? Trying to balance the right calcium level to prevent this from happening is difficult, since plaster pools need ~200ppm of calcium to prevent leeching. My input water is ~160ppm. My pool is currently ~250ppm.

 

[JasonLion]

When water from the pool or the waterfall splashes on the tile and then evaporates any calcium and salt is left behind on the tile as a white coating. The salt is fairly easy to remove but the calcium usually needs an acid treatment, as described above, to remove.

You can minimize, but never completely eliminate, this buildup by keeping the CSI of your water very slightly negative. CSI depends on nearly all of your levels, not just the CH level. That will cause any water that washes over that area and back into the pool to take just a little of the excess calcium away with it. However, there will always be areas where evaporation happens more quickly than water washing over and calcium will still accumulate to some extent.

 

[spishex]

Here's the wiki page on efflorescence if you'd like some more reading. The problem gets much worse and is pretty much impossible to manually scrub off on unsealed tile.

 

[Charlie Wathen]

Thanks for the info guys. I used the pool calculator, but not sure what CSI values I would need. Here is what it said:

Calcite Saturation Index - requires PH, TA, CH, CYA, Temp, uses Borate, Salt
Less than -0.6 is suggestive of problems for plaster, tile, stone, and pebble pools.
Greater than 0.6 is suggestive of problems for all pools.

I filled in the info and hit the calculate button. Its saying my CSI is -0.6?

 

[JasonLion]

Since your CSI is already negative, there isn't any reduction in white buildup that can be gotten by adjusting your water chemistry.

-0.6 is slightly low for a plaster pool, fine for vinyl or fiberglass. If you want further advice about CSI, or general water balancing, you should start a topic of your own in the Testing and Balancing area with your complete set of water test results.

 

[chem geek]

As spihex posted, you may have efflorescence in which case your water chemistry is not the cause and changing it won't help very much. It's basically coming from the ground (or backing behind the tile) through the tile. I get a very small amount of that in some places in my pool, but not as much as shown in your pictures. Unfortunately, I don't know what can be done to stop it.