Cleaning Calcium Scale Myself - am I crazy?

[YoPool]

Hey TFP! I have some significant calcium scale build up on my tile (see below pics - its the white haze at the top which forms an arched pattern half way down the tile). My tile is a grey natural stone (looks like slate) with a pretty matte finish. I called around and 1) can't find a pro to do it and 2) was told by one guy that everyone is so busy and understaffed that if I do find someone to do it I probably should not trust them since its really labor intensive and requires manual scrubbing with mercuric acid and if they have the time they probably aren't that good at their job....

I also have read about soda and bead blasting but finding someone to soda blast in Charlotte is proving difficult and I don't really want to drain the pool.

Sooooo, this is what I am thinking about: Using an air powered sander (something like the attached pic) with some waterproof sandpaper and a squirt bottle of mercuric acid. I started working on the scale without the sander, just using hand sanding and acid (and rubber gloves!) which got results but it was way too labor intensive . So my questions are:

1) Is this going to do more harm then good? My fear is I am probably scratching up the surface of the tile in the process of cleaning it which likely makes it more susceptible to scale in the future.
2) Is waterproof sandpaper the right thing to use? I was using 220 grit - I might start with something finer to see if it works. Or are there polishing pads that might work better?
3) When I was experimenting with hand sanding I was using full strength MA, misting it on the tile, letting it sit for a few minutes, and scrubbing off. Apart from any risks to my skin/eyes (I wore plenty of PPE and suffered no ill effects) is this going to catastrophic damage to my grout and cause tiles to fall off? The pool guy I talked to recommended 70% MA dilution. I just cant imagine it being on the grout for a few minutes causing that many issues but maybe i am wrong....
4) Anyone had luck with the chemical scale preventer as something I could apply after the removal to prevent future buildup?

 

[JoyfulNoise]

I hate to be a naysayer but it’s not likely to work. A few points -

One, it’s MURIATIC acid (otherwise known as hydrochloric acid), NOT mercuric acid. But I suspect you have the correct chemicals one hand.

A powered grinder is only going to increase the chances of tile damage while having minimal impact on how long it will take and how much elbow grease you’ll need.

Sand paper of any kind is going to grind down the tile as much as it will grind down the scale. You are going to leave some very ugly swirl marks and scratches all over the tile that will only promote more scale grown later on.

Using any kind of chemical with a rotary grinder is incredibly dangerous. You may be covered in PPE’s but nothing around you is so you can expect acid and scale debris flying everywhere. That could possibly lead to stains or damage on the coping and deck.

The correct approach is the one that you are having trouble locating - scale needs to be bead blasted off of tile. Glass bead is one type of media or kierserite (magnesium sulfate) is the other. Soda blasting uses sodium bicarbonate as the media and that is too soft to cut calcium scale with. If the bead blasting is tuned properly (pressure and flow) then it will remove the scale and leave the tile unscathed with minimal damage to the grout.

You are better off living with the ugliness of it until you can find a qualified professional to do the job rather than damage what you have there and cause a much bigger and more expensive-to-fix mess.

 

[AQUA~HOLICS]

Answer to #1: this all depends on the aggressiveness of your cleaning pad. The tile has a glaze on it and if it’s damaged the scale will even harder to remove next time.
#2: these pads are used by many service techs in my area for removing scale on pool tiles.
#3: most liquids are going to be harmful on the grout, sanding pads seem to be used the most next to glass beading.
#4: Pool Tile Restorer (picture) is a product that I tell customers to try, have yet to hear any negative about the product other than it’s a little pricey but only needs to be applied every few months.

 

[YoPool]

Thank you both for the quick reply. If anyone knows a pro in the Charlotte area that does bead or kierserite blasting please let me know!