OMG - Friend's pool numbers... followed by WTH?

[taekwondodo]

Now that I "have the summer off", my friend knew about the great things I've done with my pool in the past month, and called me up to ask if I would come over today and help her open her 10.1Kg AGP.

So, I had her get 4 gallons of Cl, some MA, some borax and some salt...

Here were the numbers I read this morning...

TC=0 (expected)
pH = VERY VERY YELLOW (what???)
Ca = ~200ppm
CYA ~100 (or more)
T/A =... get this... ZERO (OK, now the pH makes a little more sense).

And the pool walls are covered in green algae...

It turns out her (now-ex) husband took care of the pool last year. In the shed I saw half-empty buckets of di-chlor, cal-hypo shock, dry acid, pH increaser (soda ash), and... an empty bucket of stabilizer. All this next to his trusty OTO pH/Cl test kit...

Step 1: We drained the pool by about 1/3, pulled the DE filter apart, cleaned the grids and added 2 gallons of 10% to raise the FC to 20, and brushed the Crud out of the walls. The water was now dark green.

Step 2: Once the pool was refilled, we turned the pump on and added 10 boxes (10 lbs) of Arm and Hammer added to raise the T/A to 70ppm.

Step 3: Waited an hour and took a TC reading, a pH reading and a T/A reading:

• FC = 50 (??? WTH? Why was this so high... we added 2 gallons of 10%, which according to TPC should have given us ~20ppm, plus whatever came in with the 3000G of replacement water, which I don't think there's that much in the city water)
  [/*:m:1efqo98d]
• T/A = 120 - again seems high based on the 70ppm I should have got
  [/*:m:1efqo98d]
• pH = Still VERY YELLOW (one less VERY)[/*:m:1efqo98d]

So, to try pulling the pH up, we added 4 boxes of Borax to the skimmer. Waited an hour, now the pH is in the 6.5 range... (and bring Borates up to ~30ppm). We waited another hour or so, and at least now the pH is reading a little above 6.5... Note - I didn't intend to treat with Borates today, I was going to wait a few days to get everything in-line not expecting a whacked-out pH & T/A, but leaving the pool running with that very-low whacked-out pH left me with concern.

By the time I left tonight, the water was no longer green, but white (and clearing - and waaayyyyy better than where we started). But with all of the changes made to the water during the day, I think I'm going to discount the "after" numbers from today and go over there tomorrow to re-test everything (give it some extended mixing time).

CC&S are welcome and appreciated.

Thanks,

- Jeff

 

[frustratedpoolmom]

It's very nice of you to help her out.

 

[PaulR]

With an FC that high you aren't going to get a trustworthy pH reading. Don't mess with the pH again until the FC comes down below 10.
--paulr

 

[taekwondodo]

Also concerned that the Cl reading was so friggen high... I started at zero ppm TC, and added 2 gals of 10%, which should have taken the Cl to ~20ppm.

I stopped titrating around 50 or so drops and still had bright pink.

- Jeff

 

[PaulR]

Also concerned that the Cl reading was so friggen high... I started at zero ppm TC, and added 2 gals of 10%, which should have taken the Cl to ~20ppm.

Was that TC=0 result with the FAS-DPD test? It can happen that you put in the powder, and maybe it flashes pink and goes away; in that case you need to use more powder. But you'd think that would be an artifact of high FC and expect it to happen again after you added another 20ppm... doesn't make sense.

If the first test was DPD drops, then it makes total sense as the DPD bleaches out at really high FC.
--paulr

 

[lovingHDTV]

Also concerned that the Cl reading was so friggen high... I started at zero ppm TC, and added 2 gals of 10%, which should have taken the Cl to ~20ppm.

I stopped titrating around 50 or so drops and still had bright pink.

- Jeff

50 drops would be 25ppm not 50ppm

dave

 

[JasonLion]

High FC levels will make the PH read higher than it actually is. If your PH reads very low even at high FC levels then you want to raise it right away.

One possible reason the FC level might have gotten so high is that the pool might not really be as large as you think it is.

 

[taekwondodo]

OK - went over there this morning, and the pool looks AWESOME... Crystal clear, some dirt on the bottom...

Current readings:
FC = 24.0
CC = 0
CYA, Still >100 (We drained 1/3rd of the pool yesterday)
pH = 7.2

Draining another 1/2 today.

Also, the pool's ~12x24x4' Oval, which would give me 7700 gallons, but there is an 8' deep end that I added in for another 3K gallons... This could be as small as 1500 gallons (8x8x4). So the pool could be around 9300 gallons which means that, assuming the 10% Cl was "new and overcharged" - still would have only taken the Cl to 26ppm yesterday (and when I stopped titrating at around 50 drops (nice catch) it wasn't even starting to turn yet...not even close). And I can't believe the pool's any smaller than 9300, so the only assumption I can make is the Cl must have been very new.

- Jeff

 

[PaulR]

With CYA that high, you can dilute your pool water sample 50-50 with tap water and test that. Double the result. You lose a little accuracy but it's not that precise a test to begin with. Will give you a better handle on how much to drain.
--paulr

 

[taekwondodo]

With CYA that high, you can dilute your pool water sample 50-50 with tap water and test that. Double the result. You lose a little accuracy but it's not that precise a test to begin with. Will give you a better handle on how much to drain.
--paulr

Could an extremely high CYA number mess with other pool chemistry (specifically, pH)?

 

[frustratedpoolmom]

No.

My advice, do the drain/refill dance before you waste any more chems trying to balance the other numbers.

 

[taekwondodo]

I drained down 50%, and am in the process of filling...

with a single 5/8" hose (waits, and waits.... and waits...).

Should be done by late tonight, then I'll be out for a few days... (Fishing on the lower Sac with my boy!!! )

I'll have to test monday.

- Jeff

 

[krcossin]

She owes you, big time.

 

[taekwondodo]

So, back from fishing...

Went over to do a test this morning, FC ~10.5, CC=0.... and... CYA... STILL over 100! (I did a 50% drain/fill on Fri, and an earlier 30% D&F on wed).

So, I'm going through CYA reagent (yes, I'm doing it right) like it was water... So, under the advice of others, took some water home and mixed 25ml of her pool water with 25ml of RO - and got a reading of somewhere between 90-100 ppm (between 180-200ppm in PW).

Which means her pool still needs another large D&F.

(just to double-check the results, I diluted to 25% - 30ml RO and 10ml PW... reading was ~45... 45x4=180)

Note: working backwards ((180ppm/50%D&F))/(30%D&F) I estimate the CYA was somewhere between 550 and 600ppm at the start of this "little project".

 

[lovingHDTV]

I think you should get an award for that!

 

[PaulR]

So, another 2/3 drain will get you to CYA 60 which is tolerable, assuming it's a sand or DE filter the backwash/splashout over time will bring it down a little more.
--paulr

 

[taekwondodo]

So, another 2/3 drain will get you to CYA 60 which is tolerable, assuming it's a sand or DE filter the backwash/splashout over time will bring it down a little more.
--paulr

I'm a little frustrated - I should have done the dilution test first and I would have realized that we should have drained 90% of the water from the start. She's on City water and going to have quite the bill this month...

- Jeff

 

[kidsluv2swim]

So, another 2/3 drain will get you to CYA 60 which is tolerable, assuming it's a sand or DE filter the backwash/splashout over time will bring it down a little more.
--paulr

I'm a little frustrated - I should have done the dilution test first and I would have realized that we should have drained 90% of the water from the start. She's on City water and going to have quite the bill this month...

- Jeff

Just think of all the $$ she saved by having you help her out! The pool store would have taken her for a ride!!

She is lucky to have you to help her!!

 

[Aquaman95]

So, another 2/3 drain will get you to CYA 60 which is tolerable, assuming it's a sand or DE filter the backwash/splashout over time will bring it down a little more.
--paulr

I'm a little frustrated - I should have done the dilution test first and I would have realized that we should have drained 90% of the water from the start. She's on City water and going to have quite the bill this month...

- Jeff

If you call the city water billing dept. and tell them you are filling a pool they may reduce the rate...sometimes they'll credit the sewer portion of the charge.

 

[taekwondodo]

So, another 2/3 drain will get you to CYA 60 which is tolerable, assuming it's a sand or DE filter the backwash/splashout over time will bring it down a little more.
--paulr

I'm a little frustrated - I should have done the dilution test first and I would have realized that we should have drained 90% of the water from the start. She's on City water and going to have quite the bill this month...

- Jeff

If you call the city water billing dept. and tell them you are filling a pool they may reduce the rate...sometimes they'll credit the sewer portion of the charge.

Excellent idea. I'll tell her to do that.

THANKS!