High TA, CYA & CH

[w1sp3rs]

(1st Post!)
After some research, I found out that all those thin white flakes in my pool, especially in the spa, are from scaling. Here are my test results from this morning:

FC = 5.2; CC = 0; pH = 7.6; TA = 110; CH = 800; CYA = 180

I know we have hard water but I haven't tested the tap. According to Pool Math, I should drain the pool about 56% and refill with fresh water. If I do this, in what order should I be balancing the chemicals with the new water in? Salt first, then what? And do I really need to drain the water, or can I just continue to lower the pH to 7.2 as suggested and aerate the water?

My test results were a little higher last week due to a pH of 8.0, but I added acid and dropped the pH so now the levels are lower.

Note: to be able to read the CYA, I diluted the test with 1/2 tap water as explained on the Taylor site when your readings are higher than 100 ppm.

Is it possible that the scaling is forming on the filter screens and I need to clean them out? I've never opened the filter myself.:-?

What should be my plan of attack???

Other than the high TA, CYA, and CH, the water looks amazing.

Thanks,

 

[jblizzle]

Welcome to TFP!!! Salt is actually the least important, you can always add bleach to get the chlorine up.

It is more likely that the scaling is happening in the SWG cell when you let your pH get too high (combined with the high CH levels).

With both the CH and CYA so high, those would be better if you could replace at least half the water (maybe in a few steps). Once you have the CH and CYA where you want them. Then just test the pH and FC levels, adjust as needed, and then add salt (usually you want the SWG off for 24 hours after you add salt to be sure it is well mixed).

 

[Richard320]

Boy, those numbers sure look familiar to me. Except my CYA was more like 220-240 when I took over.

The 800 CH is about the practical limit to keep CSI neutral. The 180 CYA is more worrisome. You can maintain a pool with that CYA level; I've done it. But it wasn;t easy and I don't recommend it. The FC level for that CYA is 14 or more, which puts it far above the threshold where the pH test starts to react and read falsely high. And pH is critical for both skin and eye comfort as well as the formation of scale.

So you are correct that a partial drain is in order, but do it for the CYA level, not the CH. After you refill, you test things. As I see it, you're still going to have high CH, but there isn't much you can do about that where we live. Your CYA should be close to ideal, so i doubt you'll need to add any unless you drained all the water. Which leaves you with pH, TA, and FC. Our tap water has chloramines in it, so don't freak out if you see some after the refill when you never saw it before. It's not much and it will burn off in the sun in a few days. So... you test pH and TA and plug in your numbers and adjust pH to 7.2, knowing it's going to rise again shortly. Then you add chlorine bleach so you don't get algae. If it was warmer, I'd suggest you then hold Diamond Day. But most likely you'll just dump it in without any fanfare. Give it a day to dissolve and mix, recheck pH and TA and adjust as needed, and start the SWG. No big deal.

Just as an aside, the closest datapoint to Whittier shows groundwater levels are only 16 feet below the surface in a good year, so it's unlikely you'll float your pool. And you probably won't replace it all, anyway, so I'd say just calculate how much to replace to reduce CYA and do it all in one shot. gicima