Dateline Brian. Please, help! I’ve tried everything to remove hard water build-up from the tile around my pool. I’ve had no luck, and I’m at a loss. Thought you might have an answer for me.
Well Brian, the Pool and Spa Master does have an answer–actually several answers. Sadly, they all involve the age old cure for most issues—elbow grease.
The reason for the scale build-up is either high TDS (over 3000 ppm) or your chemistry (our friends, total alkalinity and pH) has been off the mark for a while.
First get your TDS tested. If your TDS is high, you might have to consider draining your pool. You can also do a half-drain and refill. Remember: If mini-stalagmites are building up on your tile, your plumbing is likely seeing the same evolution. You must also get that total alkalinity and pH balanced.

Once this is done, get a pumice stone, and a product from your pool store called, Bio-Dex 300 Tile Cleaner. Once at your pool, grease up your elbow, offer your buddies some free beverages, and provide them with the same grease for their elbows. Engage those now-greasy elbows and begin scrubbing the tile crud in 2-foot sections.
Do you use liquid chlorine? This can also contribute to scale build-up on your pool tiles. Why? Just one-gallon of chlorine contains a whole bunch of salt, which will add to your TDS issues.
Now let me slip in this purely self-promoting note: My chlorine-free pool sanitization system found at www.riptidealchemy.com, will alleviate the chlorine business and also keep the salt out of your water and make your swimming experience much healthier.
E-mail me back if you need additional information.