The pH may rise just from the agitation of filling, so check it once the water is circulating and if it's close to 7.8, push it down to 7.2. Otherwise skip that step. There's no urgent need to lower TA aggressively. Each time you add acid to lower pH, you'll also lower TA some. Just keep the pH between 7.2 and 7.8. With your high TA, pH will rise quickly, but as you continue to lower pH with acid, it will slow down. There's no reason to rush it and even less reason to stall on adding chlorine.
Originally Posted by deerhunterman51
Since it's a fresh fill, and it's tap water that already has some residual chlorine, there's no need to shock the pool. You don't have algae and never have, and if you maintain it right, you never will. Just target 3 FC since there's no CYA yet and then add the CYA.
It looks like 6 lbs of CYA granules will take your CYA from 0 to 40. So add that via the sock method and assume it's all there, even if it hasn't fully dissolved by day 2 and target 5 FC. In a few days, once the CYA is all dissolved and dispersed, you'll get a better idea of what you need to target for FC. The key point being that you never want FC to drop below 3 before you add more. So... if you target 5 and the next day when you test it shows as 2, you better target 6. Every pool is different, depending on swimmer load, debris load, sunlight, temperature, too many variables to have an absolute value.
After a week, you can recheck the CYA and if you want to add more CYA, then you can do it. But many times pools aren't as big as people think, so it's better to build up to the CYA level than to overshoot. If you do choose to raise CYA to 50, then the minimum FC will also go up.
It'll start to make sense once you start doing it.
You don't want to depend on tabs to chlorinate. Here's something I wrote a couple years ago that explains why not.
We'll take a 16000 gallon pool, because that's what I have. On a fresh fill, prominent national pool chain recommends 2.5 pounds pf stabilizer per 10,000 gallons, which works out nicely to 4 pounds which brings CYA to 30.
With an average loss of 2 PPM/Day or 14 ppm/week, I'll have added 8.6 PPM/CYA if I used trichlor pucks perfectly. And they recommend a weekly "shock" of dichlor between 5 and 10 FC.... 2-3 oz per 10,000 gallons. Split the difference; I'll add 4 oz. CYA went up another .9.
So..by the end of week one, I have added 9.5 more CYA. It is now 39.5. Mimimum FC for that is 3, so I'm probably okay.
Week two, up to 49 CYA.
Week three, 58.5. Minimum FC should be 5, but they recommend 3 as ideal, so the pool looks a bit hazy. So I'll toss in a little extra dichlor "shock" to jack FC up to 10. Which adds another 6.4 CYA. Keeping count? We're up to 64.9 now.
That caught the algae just in time.. we had two weeks of good luck. A steady diet of pucks and 4 oz. "shock" each week only added another 19, up to 73.9 now.
Week 6 it started looking funky, so we "shocked"it once again. CYA is up to 99.3. But minimum FC to keep algae at bay is 8, and we're still holding things to 3, because prominent national chain's preprinted sheet shows that as ideal. So algae got a toehold and the pool has a bit of a tint. So we throw two whole bags of dichlor in which jacks it another 7.6. By the time week 7 is over, we're at 116.4, because we had pucks in the floater the whole time.
So...in 7 weeks, from 30 to 116.4. Let's say there are no more algae outbreaks because they sold me a huge bucket of phos-free and another of yellow-out monopersulfate "shock" Nothing but the pucks and the extra 4 oz of dichlor "shock" weekly. So the next 7 weeks added 66.5, which brings the total to 182.9 CYA.
Now if we didn't understand this and things looked a bit hazy, we might throw an extra puck or two in the floater every couple weeks, which will drive it over 200 easily.