I have a 15,000 gallon gunite pool with a SWG. The water is about 5 years old (so is the pool) and calcium scaling has progressively gotten worse. For the first 2-3 years, there was little or no calcium scaling at all, with a minor exception of the natural rock at the spa overflow. Now this rock, as well as the rock on the water line in the spa has severe scaling, with minor scaling on the tile around the pool water line. My water clarity is awesome, and I have no algae since I added some phosphate removal product last summer.
I had the water tested this weekend, and the CH is 700 ppm!! In researching the water quality report from our water district, our tap water has a hardness of 250-320 ppm, so I guess after 5 years this is not surprising. It looks like a complete drain and refill is in order. In light of this, I have a few questions:
1. I am constantly battling the pH creep associated with the SWG. Is adding enough acid to bring the pH into the 7.2 to 7.4 range on a weekly basis enough? By the time the next weekend rolls around, the pH is back up to 7.8 or 8.0 which has left the pool vulnerable to scaling. Should I be adding acid every two days or so? Or adding enough to drop it to 7.0 or so, such that the average is more like 7.4 over the whole week?
2. How much will the borates help with this? I have never heard of borates before visiting this site. Is this a widely used technique, or more of a "cult following", for lack or a better term?
3. What about devices, like the mpulse 3000, that purport to change the calicum molecules into a more manageable form? This sounds like a lot of hooey to me, but I'm willing to try it if others have had good success.
4. What is the best method of removing the severe calcium scaling on my rock work? I am thinking of getting a bid for bead blasting this rock (it's natural rock) and then trying to monitor my pH more closely in the future to reduce the scaling. Acid washing will probably handle the scaling on the tile line, right?
Thanks in advance