CYA discrepancy

[brianmcb]

Here are some before pics

Here's a pic I took this afternoon (cloudy and rainy today so it looks darker overall)

 

[brianmcb]

just for kicks here are the numbers from the pool store (from last night, before i cleaned out the leaves and stuff). I verified the pH reading by testing it myself (it was 8.0 before, I was trying to drop it to 7.4 but overshot it).

pH - 7.2
TA - 62
FC - 0
TC - 7.5
CH - 140
CYA - 0

Here are my results from this morning
pH - 7.2 (might have been a tad lower than 7.2, I'm bad at reading the colors. We got 2+ inches of rain since I checked and I saw a comment from PoolGuyNJ that rain tends to lower pH in our area)
TA - 60
FC - 3
TC - 3.5
CH - 210
CYA - 0 (just started adding CYA this morning, have 2 lbs in a sock in front of a return)

I guess 2 things jump out at me:
- CH is very different than the store's reading
- CC has dropped a LOT

I've had my pump and SWG on 24/7 since the cleanup process began. I shocked last night around 7:30pm with 415 oz of bleach. Since the last test, I backwashed twice and cleaned a LOT of leaves and gunk from the bottom of the pool. Water looks similar to the last picture above, although there is quite a bit of foam on top of the water this morning.

 

[frustratedpoolmom]

Well, I'd trust YOUR CH reading...

 

[Butterfly]

Yep, trust your testing.

WooHoo, major improvements in your pond, I mean pool!

 

[PaulR]

AFTER the pool is clean, bleach is the easiest way to figure your gallons. Normally I would just say keep track of what you add and see if you consistently overshoot or undershoot your goal; but as you have a SWG, the easiest procedure is this:
1) Some evening with the pump on and the SWG off, test FC (with FAS-DPD)
2) Add two big jugs of bleach; leave the pump on
3) 1-2 hours later, test FC again
In a roughly 20K pool, two big jugs should raise FC somewhere in the 8-10 range, which is enough difference that the testing uncertainty won't dominate the results.
--paulr

 

[brianmcb]

thanks for the tip to calculate the volume, i'll give it a shot.

Do I need to wait for CYA to adjust before adjusting everything else?

From what I can tell, I need to:
- increase CYA by about 70
- increase hardness by about 90
- increase pH by about 0.5 (I assume I should wait until I'm done shocking to do this)

 

[brianmcb]

Just thought i'd update my progress

- dissolved around 3 lbs of CYA so far. i keep topping off the sock as it dissolves.
- have not backwashed for more than 24 hours and pressure on the filter is good.
- vacuumed yesterday and brushed the entire pool. very little silt left on the bottom, just a few leaves here and there.
- shocked last night with 400 oz of bleach. shut off SWG. this morning, FC was still 13! CC was 0 or 0.5, it was very slightly pink before 1 drop. turned SWG back on.
- water is crystal clear and blue, but still pretty foamy (foam seems to disappear by the time i get home from work).
- added 50 lbs salt this morning, SWG was reading 3200 ppm and they recommend 3500.

today i plan to adjust CH and pH, from what I can tell I am done backwashing and shocking.