Chlorine and pH problems following missing stabilizer

[Cstaines]

We have an 18,000 gallon pool, in ground with vinyl liner.
Hayward DE filter with a Hayward Super pump.
pH 8.0, chlorine 1.0, water crystal clear.
At the start of the season, we had no chlorine, but normal levels for other tests. When we began shocking the pool however, it became unable to hold any chlorine at all. We were told by a pool store that we needed to reach the chlorine demand and began putting tons of dichlor and trichlor tablets and granules into the pool. Well, not surprisingly, the pH of our pool went so low that the test strips no longer read it, and the stabilizer is at least 150 ppm.
After putting ten pounds of pool store pH up (sodium carbonate) into the pool, the pH was still too low to read, but the alkalinity had risen to 180 ppm. That is when we gave up on pool store chemicals and stumbled upon this website.
We added 17 boxes of Borax, which, thankfully, raised the pH to ~8.0 (admittedly a little high) but either latent effects of the pH up, or (less likely) the Borax, raised the alkalinity to even more obscene levels. We also switched to unstabilized chlorine in the form of bleach (at this point the pool would still not hold chlorine). We did one dose of 2 cups muriatic acid last night to start lowering alkalinity, and thankfully, the pH came back up after aeration as it should, although we're putting off lowering alkalinity for now.
As of today, we added 121 oz 8% bleach at 11:30, which maintained a chlorine of 1 ppm until 3:30, when we added 121 oz more. Hopefully this is a good sign, but bottom line, we just want the pool to hold chlorine the way it should and need to be able to maintain it for the summer.
I will never go to a pool store for guidance again.

[PoolDoc]

I'm glad you got the problems resolved.

What you probably encountered were the after effects of bio-degradation of the your CYA (Stabilizer) over the winter. It can take as little as a week or two of 'slimy' conditions for your CYA to began to degrade.

When that happens, the follow-on chlorine demand will sometimes be very, very high. As you discovered, using dichlor or trichlor to correct is often not ideal.

You'll probably want to take steps to avoid this next winter.

(Welcome to the forum!)

[Cstaines]

We could not follow up with you until your reply...we still have the chlorine problem. Our pool will only hold a bottle of 8.5% bleach for approximately four hours. The level rises to 3ppm and over the course of four hours drops to 1 ppm.

Our stabilizer remains at 150. Alkalinity is off the chart. PH is 7.8.

The water is clear but we are seeing fine, sandy, light in color debris gathering on the bottom of the deep end. I will vacuum thoroughly tonight.

How should we proceed?

[PoolDoc]

I wonder what your CYA was when you closed?

How are you testing? CYA tests with methods other than the disappearing dot test are not trustworthy.

Regardless:
1. Add 2 gallons of bleach at night. Doing so will gradually consume the chlorine demand, and should gradually oxidize whatever residue you have.
2. Keep the pH high, for now. Low pH tends to result in some pretty nasty chlorine+goo compounds; high pH tends to favor less nasty versions.
3. Do NOT cover your pool. Some of the compounds likely to form are removed by chlorine + solar UV, rather than chlorine alone.
4. If you aren't using the K2006 or an equivalent drops based kit with the DPD-FAS chlorine test, you need to get a K2006.
http://pool9.net/test/
5. If you have any idea what your CH (calcium) level is, say so.
6. ID your filter by make / model.


Unfortunately, cleaning up the remnants of bio-degraded CYA can be an extreme PITA. Good luck.

[Cstaines]

I will have to look up the filter model number...other than what I already posted...Hayward DE filter...
I am not sure.

CYA was 40 when the pool was closed and was actually brought back to that and fine after our first shock treatments...but when the chlorine wouldn't hold, we were instructed to until add 10 lbs of granular chlorine at a time every so many hours as we tried to get the chlorine to hold at 5 ppm for 24 hrs. Then the CYA went through the roof and chlorine just kept disappearing...along with a ton of money.

Testing with aquacheck strips and took two samples to two different pool stores and all results were the same.

When I put the two bleaches in at night, does it matter what the chlorine drops to the next day?

[PoolDoc]

1. Please post all 3 results you got (2 stores + aquachek)

2. 10# of what kind of granular chlorine?

3. Exactly what chemical was used for your "first shock treatments" . . . and how much?

4. Do you realize that each pound of dichlor granular chlorine (sodium dichloro-isocyanurate, 55% or 61% available chlorine) will add a little more than 3 ppm of stabilizer to your pool. (10 lbs => 30 ppm CYA)?

[Cstaines]

Aquacheck Between 150-200 but closer in color to 150
RP (Pool Store 1) 40 (prior to VP treatment)
VP (Pool Store 2) 150
RP (Pool Store 1) 150 (returned after VP treatment)

Initial shock was TKO which is sodium hypochlorite
Burned through many bags varying in amount per time...wouldn't hold chlorine. Most bags at once...probably six. Total used over days...probably 14. $5 a bag.

VP had us put in 10# of granular dichlor chlorine (and check every 4 hours...if FC dropped below 5 ppm add another dose)...keep going until at 5 ppm for 24 hours without treatment. 25lbs sold for $99 and we used almost 3 before we lost hope...did nothing...money gone and CYA now sky high. We were desperate to get this cleared up...graduation party in three weeks, so we got sucked right in.

Then we found your website and hope to finally get back on track...even if it means draining and refilling.

Yes, we have come to realize the fatal CYA advice from the second pool store. I have enlisted my daughter's help now...she has been reading many of the posts on your website and applying the chemistry she knows and then explaining it easier terms for me and my husband to understand.

[PoolDoc]

Aquacheck Between 150-200 but closer in color to 150
RP (Pool Store 1) 40 (prior to VP treatment)
VP (Pool Store 2) 150
RP (Pool Store 1) 150 (returned after VP treatment)

No idea what your abbreviations are, nor what the numbers are for.

Please report results in some form like this:

FC (free chlorine): store #1 => x.x; store #2 => y.y; Aquachek => z.z
and so on for
pH
TA (total alkalinity)
CH (calcium hardness)
CYA (cyanuric acid).

And . . . do NOT drain your pool. Draining an in-ground vinyl pool typically destroys the liner!

VP had us put in 10# of granular dichlor chlorine (and check every 4 hours...if FC dropped below 5 ppm add another dose)...keep going until at 5 ppm for 24 hours without treatment. 25lbs sold for $99 and we used almost 3 before we lost hope...did nothing...money gone and CYA now sky high.

Are you saying you've used 3 x 25lb of dichlor?

[Cstaines]

Sorry. Trying.

Those are CYA readings:

CYA : Aquacheck => between 150 and 200, color closer to 150; store #1 => 150; store #2 = 140

I will get another sample tested tomorrow as the last printout I have from store #2 was prior to the 10 # of Aqua Prep they had me put in the pool to raise the Ph...which put my TA through the roof. I will post those results after I swing by Store #1 at lunch. I really wish I had known about this site sooner.

TC and FC have not been sustained for more than 8 hours on their own above .5 using OTO kit we purchased.

[PoolDoc]

Got it on the CYA; need the other numbers.

And again:

Are you saying you've used 3 x 25lb of dichlor?