BBB fully inplemented - test results?

[jcichocki]

Well the BBB method has landed!! Pool looks fantastic and has never been more "sparkley". I have several questions, many regarding test results and the micromanagement of the results.

1. Results approx 2.5 weeks ago: TC 3 FC 3 CC 0 pH 7.0 Alk 210 CYA 20 ish CH 390 Borates 20 Salt 1510

(Spent 2 weeks getting Alk down. Took 14 gal muratic acid .)

2. Last Fri morning before borax: TC 5 FC 5 CC 0 pH 7.2 Alk 60 CYA 20 ish CH 510 Borates 20 Salt 1920

(Finished adding the Borax/acid per the calculator.)

3. Sat morning: TC 3 FC 3 CC 0 pH 7.4 Alk 100 CYA 20 ish CH 500 Borates 50 Salt 1920

(Turned on CAT controller and calibrated the pH. ORP read 565 and Stenner bleach tank immediately kicked on.)

4. Last night: TC 2 FC 2 CC 0 pH 7.5-7.6 Alk 100 CYA 20 ish CH 510 Borates 50 ORP 650

Am I good?? The system/pool seems to be on autopilot (sorry PoolSean not your Autopilot, yet). Looks great, smells great, etc. Do I need to re-lower the Alk? Is my CYA at 20 ish OK (still can barely see the dot with tube full on 30 scale)? And why did my CH jump? Do I need to fix it?

Thanks for the ongoing help.

 

[JasonLion]

I would raise CYA to between 30 and 50. Raising CYA will lower your chlorine consumption.

The ideal TA with bleach is between 70 and 90, but 100 should be fine. You might as well leave it alone for now.

The real mystery here is the sudden CH increase. One possibility is that you lowered PH too far at some point while lowering TA and dissolved some calcium out of the pool surface. It would also be a good idea to measure TA and CH in your fill water, which is another possible source of CH.

Do you also have PH regulation? If so, what are you using to control PH? CO2 systems can raise the TA, in addition to lowering PH, which could be a long term problem.

 

[jcichocki]

My pool is INDOOR. Should I still raise the CYA? I had lowered the CYA because of th indoor issue and no sunlight.

I wondered about the low pH and the gunite. When I measured the pH during the Alk lowering/aeration process the tests always showed 7.0. Is this a damage issue if in fact it is from the low pH.

I have an autofill feature but have not replaced any significant water volume. I fill the pool with my house "soft water" system. I do have very hard water from the tap, it tests appox 400-450. Which is why I connected the autofill to the soft water.

The pH is managed by the CAT controller and a dedicated Stenner tank with muratic acid. The controller is set to maintain a pH at 7.5.

 

[JasonLion]

Sorry, no need for more CYA. I missed the indoors in your signature.

The PH would have needed to be well below 7.0 to have caused a problem. If the calcium came out of the plaster because of low PH there would be some very minor damage to the surface.

If you are using the PH sensor in the CAT controller, it will read PH well below 7.0 correctly. However, some other PH tests show levels well below 7.0 as 7.0, others as 6.8.

It isn't at all obvious where the calcium came from if it wasn't the plaster. Unless you added some cal-hypo (in some powdered shock products)? Though that hardly seems likely.