Just painted my old 45 year old fiberglass pool and refilled with well water.

I've just repainted my 45 year old, 30,000 gallon, fiberglass pool and refilled it with my highly alkaline well water. I have a Pool Solutions PS233 test kit and when measuring the total alkalinity the reagents are turning from light blue to a somewhat green/yellow instead of turning from green to red. The kit instructions say that this can be due to high oxydizer levels but my DPD powder test is only show about 2 ppm of chlorine. Regardless, on the basis of the blue to yellowish color change I believe the total alkalinity of the water to be in the range of 286. The ph is showing between 7.8 and 8.2. I've been aerating the pool for several days and have so far added about 1/2 gallon of muriatic acid and about 3 gallons of chlorox. The other odd (to me) thing I've noticed is that the ph seems to have risen over the past couple of days. The day I completed filling the pool the ph was on the order of 6.8 and 7.2. I'm in Columbus, Ohio and we have had a bit of rain since the pool was filled. I guess my questions are: Shall I add more Muriatic Acid and continue aerating? I normally add my stabilized chlorine through an in-line chlorinator but haven't restarted that process yet. Should I wait until the ph and TA drop? Should I continue to add Chlorox to at least maintain some sanitizer in the water while the pool is finding its normal levels? I've had great success over the past several years using the combination of Chlorox, 3 inch chlorine tablets and Borax but it's been so long since I've had to do a major water overhaul that I'm a tad insecure about my current situation. Any assistance would be greatly appreciated.

Geoffrey

You definitely need to keep a sanitizer in the water, because the last thing you want to add to the mix is an algae bloom!! There's no reason I can see why you can't go ahead and use your inline chlorinator. I've never repainted a pool, so I don't know if there's any "curing" process that has to happen, but you're going to have to keep some chlorine in the pool in one form or other, especially until you get some stabilizer in there, and since it's all just chlorine when it mixes in water, it doesn't really matter whether it comes from bleach or trichlor tabs.

When you aerate the water, it causes the pH to rise, which is part of the TA lowering process. Sounds like it's working out just like it's supposed to, just trust yourself and stay with the process!! One thing to consider, though--how much topping off do you have to do? If you take the time and trouble to lower your TA, and then have to refill frequently with high TA water, then you're going to be fighting a losing battle by trying to keep it low. Where did you keep your TA in previous years?

Thanks for your quick response. The TA in this pool normally runs between 110 and 125. I tend to keep the chlorine pretty high, in the range of 10 ppm. In this scenario the ph will usually run fairly low, in the 6.8 range. You didn't mention if I should hit the pool with anymore muriatic acid. What do you think?

Geoffrey

If you want to continue to lower the TA, you'll need to use the acid to drop the pH to the 7.0 range and then aerate to raise the pH back up, like you've been doing. If you are at a point with the TA where you want to stop, then I would add enough acid to get the pH back to the 7.2-7.8 range.

Janet

When my pool has found its balanced range I find that my pH normally falls consistantly as a result of being constantly fed with tri-chlor tablets. Unfortunately simple aeration isn't usually enough to maintain my proper pH level so I use borax to bring it back up. I do have to top of the pool from time to time but since I'm normally aerating TA isn't usually a huge problem after refilling. I will continue as you suggest lowering the TA with muriatic acid to get it back into its normal range. I certainly appreciate your positive reinforcement on all of this. I have been wondering if there is a source out there to buy borax in bulk. Any suggestions?

Thanks again,

Geoffrey

I don't know about bulk Borax but remember that trichlor is self limiting and that as your CYA goes up so does your FC requirement - refer to Ben's Best Guess chart.

How are you aerating? If you could make the splashing more energetic, it could lower you Borax requirement since you TA is already so high.

To splash my pool I simply have a length of flexible pipe screwed into the poolside water inlet that's aimed above the water surface. It's not exactly pretty but is reasonably energetic. It had been 8 years since I last fully drained the pool for painting and I'm sure that in that time a lot of CYA had accumulated in the water. As of yesterday I had manged to get the TA down to 230 but obviously I've still got a ways to go. I am going to more closely watch my CYA in the future and hopefully reduce my trichlor input which should also reduce my borax requirements. I've been a follower of Ben's for years and have always had good results. At this moment, despite the high TA, the water in the pool is the clearest I've ever seen. It's simply stunning. I guess it was due for a change!

Thanks,

Geoffrey