Help with CA After Ascorbic Acid Treatment

[muffin_dad]

Hi all, did the Ascorbic Acid treatment last Thursday/Friday - I used 6 lbs since the stains were really really bad.

Since Saturday I've dumped 6 gallons of 10% bleach and can't keep the FC up. I did the overnight test last night it was 4.5 - 5 ppm, then this morning before sunrise it was down below 2. Put another 64 oz in and tonight after all day in the sun it was back to 0.

CYA level is between 30-40, Ph is 7.5.

Not freaking out yet, just was wondering if there is some calculation of how much bleach it takes to neutralize the added AA.

Thanks in advance for responses and thoughts.

 

[JasonLion]

It can take quite a bit of chlorine to neutralize the AA. It is also common enough to get algae when doing an AA treatment. There is no easy calculation for how much chlorine because there is no way of knowing how much of the AA was used up dealign with the stains.

Since you still had some FC in the morning, you should have now neutralized the AA. As long as there is AA in the water, there won't be any chlorine left after a couple of hours.

 

[muffin_dad]

No algae at all and the chlorine I add keeps getting used up. Guess I'll keep adding!

Sent from my HTC One using Tapatalk

 

[muffin_dad]

I added 242 oz of 10% clorine before a trip last Thursday. Came home yesterday to 0% and a cloudy pool (but not green) and bubbles from the spa spillover. Added another 242 oz of 10% last night, FC was 0 again this afternoon (was raining this morning and I didn't check).

Tested CYA again and now it is 0!!! I have no idea what could have caused it to go from 30-40 5 days ago to 0 today.

I will be adding liquid CYA tomorrow - question is should I add that first then the SLAM it?

- Ph 7.5 (planning to lower before I SLAM)
- FC 0
- CC .5-1
- CYA 0

Didn't test the others, I can if it's relevant.

Thanks!

 

[JasonLion]

Start the SLAM process using an FC of 10 as your target level, then after the second chlorine addition start adding CYA.

There is a kind of soil bacteria that sometimes grows in the water which breaks down CYA. Normally it only does this when the pool is closed for the winter, but very rarely it can act fairly quickly.

 

[muffin_dad]

Thanks for the reply, I had read about the bacteria - wierd.

As I'm not 100% certain it is the bacteria, is there any chance that the R-0013 reagent can go bad?

I'm presuming the idea here is to a) kill the bacteria then b) SLAM killing anything that remains...

 

[JasonLion]

There is a very very remote chance that the test reagent has gone bad. We can't rule it out, but it doesn't seem at all likely.

Yep, you have the idea.

 

[muffin_dad]

Posting updates to keep track of what I've done.

- ruled out reagent failure by testing neighbor's pool for CYA - it was 60
- reconfirmed that mine was 0
- ph at 7.0
- FC .5 before beginning

- Added 4.5 121oz jugs of 8.25% bleach
- tested 1 hour later - FC 2.5 !!!!!!!
- Added 3 more jugs of 121oz 8.25% bleach
- tested 30 minutes later - FC 5 / CC 1

So we are killing some **** here I think (with CC high) but I can't even get FC close to 10. Should I dump the rest of the bleach in that I have, add CYA then check in the morning?

 

[muffin_dad]

1.5 hours later:

- FC level down to 4 / CC .5 or less
- Added 6 more jugs of 121 oz 8.25% bleach
- Brushed down stairs, tanning ledge and walls/floors

 

[muffin_dad]

- 2am FC 14, CC .5
- 7:45 am - FC 4.5, CC .5

Adding CYA and more bleach

 

[muffin_dad]

8am

- Added 3 more jugs of bleach (targeting 14-15 FC)
- Added 2 jugs of liquid CYA

 

[muffin_dad]

9:30am

- FC is 15.5, CC 0

Making progress. Will hold it at 15 today and try the OCLT

 

[muffin_dad]

11am

- FC down to 13
- Added 75 oz of bleach to hold at 15