We have a moss rock waterfall and edging around the backside of our pool. We are in the midst of having travertine put down for decking and coping. Now that the pool is drained and new travertine is down the calcium buildup on the moss rock at the waterline looks horrible. We’ve tried scrubbing it, power washing etc and nothing is working. Our pool guy told us that doing the bead washing won’t help because it’s probably through the stone now. Any suggestions?
Calcium buildup
- Thread starter familyspencer
- Start date
- Jul 21, 2013
- 52,204
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Welcome to TFP.
Ignore it and refill your pool. Once you have water in your pool no one will be examining your moss rocks.
Ignore it and refill your pool. Once you have water in your pool no one will be examining your moss rocks.
- May 23, 2015
- 24,380
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
There really needs to be a better eye-roll emoji for statements like this made by “professionals” … no, the calcium did not go through the rock. Good Lord I need a “head bangs into desk” emoji 
Yes, glass bead or kierserite blasting WILL REMOVE the calcium scale but you want to do it BEFORE you refill the pool.
Why is that crazy?
How much do you think it should cost?
What is the time estimate?
There's specialized equipment and there's also setup, cleanup and several hours of specialized work.
Crazy in that I had no idea in would be that much due to my ignorance on the process.
Will it damage the rock? That’s what our pool guy said. That it would etch it and also make it weaker.
Yes, glass bead or kierserite blasting WILL REMOVE the calcium scale but you want to do it BEFORE you refill the pool.
What type of rock is it?
Can you show pictures?
It's hard to give good advice if we can't even see what you have.
- May 23, 2015
- 24,380
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Assuming the person doing the blasting is skilled and knows what they are doing, then yes, it’s entirely safe. Kierserite media (magnesium sulfate) has a hardness that is just slightly higher than calcium carbonate. When the air pressure of the blasting gun is adjusted properly, the media will easily cut through any scale and stop at the stone surface. It’s very effective at removing scale but it’s best done when the pool is empty as you don’t want magnesium sulfate to build up in your pool water.
Is that real rock or manmade artificial rock?
If it is real, what type of rock is it?
If it is real, what type of rock is it?
If it is real rock, a good blaster should be able to clean it without damage.
Different types of rock have different hardnesses and they react differently to abrasion.
The blasting media needs to be selected to be effective without being overly aggressive based on the type of stone.
If it is manmade, then it might get damaged depending on how it is constructed.
Make sure that the blaster examines the rock and tells you if they can guarantee that they can clean the rock without damaging it.
I would also be there as they do a test spot to verify that the cleaning works without damaging the rock.
Different types of rock have different hardnesses and they react differently to abrasion.
The blasting media needs to be selected to be effective without being overly aggressive based on the type of stone.
If it is manmade, then it might get damaged depending on how it is constructed.
Make sure that the blaster examines the rock and tells you if they can guarantee that they can clean the rock without damaging it.
I would also be there as they do a test spot to verify that the cleaning works without damaging the rock.
Acid cleaners can also be effective, but they can damage certain types of rocks.
Some rock types are not affected by acid and other types are affected quite a bit.
You can try scrubbing with a descaling solution in an inconspicuous spot to see if it works without damaging the rock.
Some rock types are not affected by acid and other types are affected quite a bit.
You can try scrubbing with a descaling solution in an inconspicuous spot to see if it works without damaging the rock.
A commercial descaler solution might work.
Something with sulfamic acid or citric acid might work without damaging the stone.
Always try a test spot for effectiveness and safety.
Something with sulfamic acid or citric acid might work without damaging the stone.
Always try a test spot for effectiveness and safety.
- May 23, 2015
- 24,380
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I honestly believe blasting it will be the easiest way to go. Certainly more expensive but a good tech knows how the clean off scale without damage. Kierserite media will have the highest chance of success as it is ideally suited for removing scale with damaging the underlying substrate. They can easily test a small area to see if it will work.
Chemical etchants can leach minerals out of the rock and “bleach” the area treated. You’d only want to do this before the new plaster is in place or else any runoff from the chemical etching can stain the plaster.
On a side note, when you do get the surface replastered, if the applicator plans to do any aggregate exposure using acid make sure they mask off the stones. If they don’t and the acid hits the stones, any runoff will stain the plaster. Ask me how I know that
Chemical etchants can leach minerals out of the rock and “bleach” the area treated. You’d only want to do this before the new plaster is in place or else any runoff from the chemical etching can stain the plaster.
On a side note, when you do get the surface replastered, if the applicator plans to do any aggregate exposure using acid make sure they mask off the stones. If they don’t and the acid hits the stones, any runoff will stain the plaster. Ask me how I know that
- May 23, 2015
- 24,380
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Bicarbonate is too soft and it’s better suited for removing paint from soft metals like aluminum or graffiti from walls.
Dry ice is a neat idea but I have yet to find anyone that’s doing it for pools. It would be an awesome process for pools because it would leave nothing behind in the water but the scale it removes. The equipment is very specialized though and expensive. I would love to give it a try.