Calcium on swimming pool tiles
Discussion
For some reason this year we have a hard calcium deposit on the pool tiles - very rough to the touch. The pool was (expensively) re-tiled last year..
A brush won't shift it - anyone here had experience of dealing with this?
From a read around the internet, it sounds like draining the pool and bead blasting is the only way - to be honest I don't really want to go to all that hassle in the summer, I'd rather wait until I shut the pool for the winter.
jjones said:
Sure it is calcium and not residue from grout?
I'm pretty sure it's not residue from grout, the grout had fully dry bonded when it was tiled... I had it re-tiled last year at the start of the summer by the same firm who built my last pool. The tiles were mirror smooth all through the summer and my last pool stayed mirror smooth for 8 years or so. When I opened it this year I had to use a lot of shock to clear a massive algae growth, I assume I upset the water balance and made the water hard.The tiles are now rough to the touch on the walls but quite smooth on the bottom of the pool.
Simpo Two said:
Calcium is a metal which spontaneosuly combusts in air, so I doubt it's calcium...
I think he might mean calcium carbonate which is the primary cause of hard water. 
http://en.wikipedia.org/wiki/Calcium_carbonate
Maybe a very large pot of 'Viacal' or vingear, but probably not very helpful...
Doesn't matter how hard you shock it, chlorine won't fix this. When did you last do a water analysis? Sounds to me like your pH is all out of whack. You need to hit it with muriatic acid, I think - but you need to test it to figure out how much. If it's calcifying as you have described, you are going to need quite a lot (maybe 3 or 4 pints, depending on your pool volume). Have you absolutely knocked down all of the algeal bloom? Is this an outdoor pool?
Edited by Matt Harper on Tuesday 25th May 22:38
NDA said:
A brush won't shift it - anyone here had experience of dealing with this?
A friend of mine had similar, actually a lot worse he had mini stalagtites, he had his acid washed. A four inch pump empties a pool real fast
I suggest you get it done as that roughness WILL get worse.
Tip for next time you get the urge to throw multiple bags of Calcium Hydrochlorate. Use liquid Chlorine for openning the pool in the Spring it will greatly reduce you disolved solids.
Algercide a month earlier helps too.
Matt Harper said:
Doesn't matter how hard you shock it, chlorine won't fix this. When did you last do a water analysis? Sounds to me like your pH is all out of whack. You need to hit it with muriatic acid, I think - but you need to test it to figure out how much. If it's calcifying as you have described, you are going to need quite a lot (maybe 3 or 4 pints, depending on your pool volume). Have you absolutely knocked down all of the algeal bloom? Is this an outdoor pool?
I think you're right about the PH, it looks very low at the moment. The algae has definitely gone, the pool is sparkling, and yes, outdoor pool. Would the acid simply remove the calcification, or does it need adding and then the walls scrubbing?jeff m said:
Tip for next time you get the urge to throw multiple bags of Calcium Hydrochlorate. Use liquid Chlorine for openning the pool in the Spring it will greatly reduce you disolved solids.
I think I will do this in future - I used to use liquid chlorine, but it was too bulky for regular use, however, for opening, I think that's a good suggestion.Simpo, 'shock' is adding a type of unstablised chlorine.
NDA said:
I think you're right about the PH, it looks very low at the moment. The algae has definitely gone, the pool is sparkling, and yes, outdoor pool. Would the acid simply remove the calcification, or does it need adding and then the walls scrubbing?
Do you do the chemistry yourself - or are you giving a water sample to a pool store/specialist?The pool construction, in part, is going to determine the remedy. I'm assuming you have an in-ground pool - is it gunite/marcite or ceramic tiled throughout?
The pH can be neutralized by adding muriatic acid, which will effectively dissolve the solid build-up back into the water chemistry - but I don't know enough about ceramic tiled pools to suggest dumping a lot of corrosive into it.
My pool is marcite with a ceramic perimeter tile and DE filtration. Any chrystaline deposits have been nuked by carefully measured doses of muriatic, in proportion to the overall volume and the pH steady balance.
I get a lot of fluctuation in steady-state pH due to high daytime temps and very high summer rainfall. If I don't monitor and adjust every 3 days or so my pH can quickly get away from me.
For all the benefits of pool ownership, they can also a bit of a pain in the arse.
MBHappyBunny said:
I had a similar issue last year. I heavily dosed the pool with PH reducer to make the water more acid. It was gone in 48 hours and the pool wall has never looked cleaner.
Of course, remember to bring the water PH back to normal before swimming ;-)
Was your issue the same - i.e. hardened calcium on the tiles?Of course, remember to bring the water PH back to normal before swimming ;-)
Matt, my pool is ceramic tiles throughout and an in ground pool....
I was swimming in it yesterday and tried to shift the calcium with a wire brush in one small area - no luck. It's really hard... It would be great if lowering the PH made it disappear, but I suspect it won't. Could this damage the grouting?
NDA said:
I was swimming in it yesterday and tried to shift the calcium with a wire brush in one small area - no luck. It's really hard... It would be great if lowering the PH made it disappear, but I suspect it won't. Could this damage the grouting?
Test the water - calcium concentration should be between 80 and 150ppm.How long has it taken for these deposits to appear?
Are you in a particularly 'hard water' area?
Are they just at the water-line?
Are they just on the grout?
Balancing pH with muriatic acid will (but not instantaniously) breakdown calciform build-up - but you have to keep on top of the chemistry - or it will just reform. Weekly brushing of walls and floor is also a PITA pool routine that will keep things in check, once you get the chemistry back in range.
You need to fix this, because your underground plumbing/filtration and heating system may be affected too.
I'm sure I don't need to spell this out, but be bloody careful handling muriatic - it's nasty stuff - very highly corrosive.
Matt Harper said:
Test the water - calcium concentration should be between 80 and 150ppm.
How long has it taken for these deposits to appear?
Are you in a particularly 'hard water' area?
Are they just at the water-line?
Are they just on the grout?
Balancing pH with muriatic acid will (but not instantaniously) breakdown calciform build-up - but you have to keep on top of the chemistry - or it will just reform. Weekly brushing of walls and floor is also a PITA pool routine that will keep things in check, once you get the chemistry back in range.
You need to fix this, because your underground plumbing/filtration and heating system may be affected too.
I'm sure I don't need to spell this out, but be bloody careful handling muriatic - it's nasty stuff - very highly corrosive.
The calcium formed at some point between switching the pool off in September last year and last month. How long has it taken for these deposits to appear?
Are you in a particularly 'hard water' area?
Are they just at the water-line?
Are they just on the grout?
Balancing pH with muriatic acid will (but not instantaniously) breakdown calciform build-up - but you have to keep on top of the chemistry - or it will just reform. Weekly brushing of walls and floor is also a PITA pool routine that will keep things in check, once you get the chemistry back in range.
You need to fix this, because your underground plumbing/filtration and heating system may be affected too.
I'm sure I don't need to spell this out, but be bloody careful handling muriatic - it's nasty stuff - very highly corrosive.
Yes I think our water is quite hard.
No, not just at the water line. From the water line to the curve that meets the bottom - but not on the bottom.
As you say, a pain.
Do you think lowering the PH would be an idea with soda ash or whatever? Would that make the water more acidic?
NDA said:
The calcium formed at some point between switching the pool off in September last year and last month.
Yes I think our water is quite hard.
No, not just at the water line. From the water line to the curve that meets the bottom - but not on the bottom.
As you say, a pain.
Do you think lowering the PH would be an idea with soda ash or whatever? Would that make the water more acidic?
I don't want to guess here - and potentially mislead you. There is a guy on here (from Australia I think) called Tim The Pool Man - he is way more knowledgeable than me. I learned the hard way - making lots of mistakes, as I went along.Yes I think our water is quite hard.
No, not just at the water line. From the water line to the curve that meets the bottom - but not on the bottom.
As you say, a pain.
Do you think lowering the PH would be an idea with soda ash or whatever? Would that make the water more acidic?
I think you could end-up chasing your tail a bit by using sodium carbonate - and you might have to put up with a milky pool for a long time until it stabilaizes.
I wouldn't wing it if I were you. I'd take a mid-water sample to a pool specialist and I think the aggressive recommendation will be a heavy hit of muriatic over a period of several days - maybe even weeks.
When you closed-down the pool last year, what chems did you add - or did you just cover it and leave it to it's own devices?
High total alkalinity can damage your plumbing and render chlorine far less effective as a disinfectant - it can be a bit of a fanny-around to get it sorted - adding doses of acid over a period of time, until your chemistry is stable.
You really need to get it tested, so you know what you are up against.
Sorry I can't be more helpful.
Matt Harper said:
NDA said:
The calcium formed at some point between switching the pool off in September last year and last month.
Yes I think our water is quite hard.
No, not just at the water line. From the water line to the curve that meets the bottom - but not on the bottom.
As you say, a pain.
Do you think lowering the PH would be an idea with soda ash or whatever? Would that make the water more acidic?
I don't want to guess here - and potentially mislead you. There is a guy on here (from Australia I think) called Tim The Pool Man - he is way more knowledgeable than me. I learned the hard way - making lots of mistakes, as I went along.Yes I think our water is quite hard.
No, not just at the water line. From the water line to the curve that meets the bottom - but not on the bottom.
As you say, a pain.
Do you think lowering the PH would be an idea with soda ash or whatever? Would that make the water more acidic?
I think you could end-up chasing your tail a bit by using sodium carbonate - and you might have to put up with a milky pool for a long time until it stabilaizes.
I wouldn't wing it if I were you. I'd take a mid-water sample to a pool specialist and I think the aggressive recommendation will be a heavy hit of muriatic over a period of several days - maybe even weeks.
When you closed-down the pool last year, what chems did you add - or did you just cover it and leave it to it's own devices?
High total alkalinity can damage your plumbing and render chlorine far less effective as a disinfectant - it can be a bit of a fanny-around to get it sorted - adding doses of acid over a period of time, until your chemistry is stable.
You really need to get it tested, so you know what you are up against.
Sorry I can't be more helpful.
Matt, you've been very helpful. I'll get the water tested.......
NDA said:
I just covered it.
Hmmmm - this is probably the root of the problem.On the assumption that the pool is located in the UK (and I was never in a position financially, to own a pool there - so have no DIRECT experience) - there is a 'winterising' procedure that you need to adopt when you close-down the pool at the end of your swimming season.
Aside from draining-down the plumbing and lowering the pool level quite substantially (to prevent the skimmer from ingesting anything that could freeze) you should add a variety of chemicals to stabalize the water for a protracted period. I'm sure you can google the close-down procedure - thankfully I don't have to piss-ball around with this process - but I'm betting that if you effectively 'winterize' next time, you won't see a recurrance of this issue.
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