Sandblasting A Tile Pool?

[jaideeguy]

I want to recover my neglected tile pool that has a heavy calcium buildup and the last time i drained and cleaned it, it was a toxic nightmare with muriatic/hydrocholoric acid and lots of physical scraping with a crew of 5 workers in the heat and toxic fumes.....no fun.

so, I am wondering if it would be safe for the tile to hire a sandblaster and just do it. Would the sandblasting damage my tile??

And where would I find a sandblaster company??

[stolidfeline]

It will destroy the glazing on the tiles, and that will allow bacteria and deposits to build far more rapidly than before.

[jaideeguy]

That's what I was afraid of......

Any ideas short of harsh chemicals and hard labor??

[chrgrims]

i presume you have tested the water? what is the calcium hardness level?

[buckhumyai]

Unfortunately Acid is really the only suitable treatment available for calcium scale. There are chemical companies developing various products however they are more maintenance based then a cure for an existing problem. Obviously I have not seen the pool but depending on just how bad it is, a lazy option our company use over winter when no one is swimming is to pour 20L Acid straight into the water and let it slowly dissolve the calcium over a few days whilst brushing each day. Eventually it will loosen and come off the wall and start to fall to the bottom or dissolve into the water. If you maintain a very low pH the water begins to re absorb the calcium. It is then a matter of filtering as much calcium out of the pool as you can and then rebalancing the water. I usually drain at least half the water and replace it with fresh water.

The fact you have had to do this before suggests you have high calcium in your water and you must maintain your pH at 7.2 - 7.6 or you will face this problem continually

Finally if you are using powder chlorine here in Thailand it is imported from China and is utter rubbish. It is full of fillers and usually about 40% calcium. You should move to 90% pure chlorine which is much much better or you must mix the cheap nasty chlorine into a bucket and dissolve it. Only pour the liquid into the pool (which is the chlorine) and discard the fillers/calcium anywhere else except into your pool.

Cheers and good luck.

[jaideeguy]

Yeah.....it tested high calcium hardness levels and my home test of water hardness is to pour a few drops on my truck hood and see how much residue is left when evaporated. Our house/well water is super saturated with calcium....constant ly having to clean water fixtures with acid solution.

[jaideeguy]

Unfortunately Acid is really the only suitable treatment available for calcium scale.

That's too bad, as it is one of the nastiest jobs that I have done.

Obviously I have not seen the pool but depending on just how bad it is, a lazy option our company use over winter when no one is swimming is to pour 20L Acid straight into the water and let it slowly dissolve the calcium over a few days whilst brushing each day. Eventually it will loosen and come off the wall and start to fall to the bottom or dissolve into the water.

No one is swimming in it, as I just let it turn green and zero maintenance. So, no problem with adding acid.....if it will disolve the calcium scale faster, I'll add more acid [muriatic or hydorcholoric?]........and you're saying that the calcium will just flake off the tile to the bottom and can vaccume out to waste?

I usually drain at least half the water and replace it with fresh water.

The fact you have had to do this before suggests you have high calcium in your water and you must maintain your pH at 7.2 - 7.6 or you will face this problem continually

I have always been in that range of PH and replacing the water will not be an easy chore, as the lake that I usually fill from is dangerously low from droubt conditions up here in Chinag Mai.

You should move to 90% pure chlorine

That's what i use......90% trichlor slow release granuels from Japan @ 4,000thb+/50kg

[chrgrims]

dam_n, i am glad our water is low on calcium. I actually added some, because my testing showed that i had far below the recommended level.

[buckhumyai]

Dont bother draining and replacing water if all you are going to do is top up with hard water again. It defeats the purpose. The idea behind replacing water is to lower the calcium level by topping up with fresh water low in calcium.

Glad you are using the best chlorine otherwise if you were using calcium based chlorine you would be having even worse problems.

Muriatic acid and Hydrochloric acid are one and the same. The term Muriatic acid is not used so much these days but they are both the same and have the chemical formula HCL and are usually sold at around 35% strength.

Just pour the acid around the edges of the pool and lightly brush the pool. The water will begin to immediately absorb the calcium scale and within a day or so it should start to soften and loosen from the tiles. You can vac to waste if there is a lot of scale however it will eventually dissolve into the water.

There are four factors which affect water balance pH, Alkalinity, Calcium hardness and Temperature. If one of these levels is way out, in your case the Calcium level, and there is no viable way of correcting it then you need to adjust the other levels to compensate.

At the moment your water is not balanced and is what is known as scale forming ie calcium scale. Water can be either corrosive or scale forming or perfectly balanced in the middle. You need to lower your pH and Alkalinity of your water in an attempt to balance the water. I would maintain your pH at 6.8 - 7 and your alkalinity at 50 - 60 ppm and this will greatly reduce the amount of scale buildup in the future. However due to the high calcium level of your water source you will continue to have problems with scale but you can limit the effects by being a bit more vigilant on the water balance.

[Valentine]

Something that could be contributing to your problem is calcium leaching out of the concrete & coming through the grout. I have seen this many times & is usually because no waterproof membrane has been applied before tiling.

[LeungKen]

A friend of mine had a similar problem & solved it by installing a pvc membrane.

Check out the Desjoyaux site for more info, maybe it's a viable alternative solution for your problems.

Cheers & Good Luck

[jaideeguy]

Mine is definately from the ground water that I use to top off the pool. A lab tested the 'total alkalinity and max was 150.....mine came in at 250 [ppm, I think]. And further proof of it is water staining of anything glass....mirrors, glasses, counter tops, truck and even the faucets.

A membrane would get stained just as fast as my tile.

I may experiment with buckhumyai's advise on a smaller pool that I have and if it works, then I'll get an amount for my larger pool, which is 84cu mt.

[Valentine]

Mine is definately from the ground water that I use to top off the pool. A lab tested the 'total alkalinity and max was 150.....mine came in at 250 [ppm, I think]. And further proof of it is water staining of anything glass....mirrors, glasses, counter tops, truck and even the faucets.

A membrane would get stained just as fast as my tile.

I may experiment with buckhumyai's advise on a smaller pool that I have and if it works, then I'll get an amount for my larger pool, which is 84cu mt.

A waterproof membrane on a tiled pool is applied to the concrete surface before tiling. Many so called "pool builders" do not follow this very basic guideline when building a pool.

Silly question but have you tried reducing the hardness with soda ash? You have to be careful as it can also increase the pH but is much more user friendly than handling acid.

[PoolDoctor]

After maintaining, repairing, renovating and tiling at least a hundred pools in Thailand, I thought I had seen everything. Alas, even an old dog learns new tricks. My own pool developed a leak, but we were on several big jobs and I had no extra staff to come and fix it for me. It was the cold season anyway, so I drained it, and let it go. Sure enough, effloressence set it, and covered the pool in ugly deposits. They're too hard for scotchbrite, but a chisel would scratch the tile. Hmn. Dilema. Then, I noticed one of my guys making rapid headway in the corner. Viola! He was using a bit of broken tile, and it works perfectly. Its just slightly softer than the good tiles, but hard enough to remove the calcium deposits. Its also fast! Picture here.