What Next - - partial drain and refill? SLAM?

ladylonghorn

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Jan 14, 2016
31
Frisco, TX
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16700
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Chlorine
Liquid Chlorine
2 local pool supply stores + newly hired pool maintenance = 3 entirely different numbers on CYA.

Trying to take control so per guidance here I ordered a Taylor K-2006 complete FAS DPD test kit - - it just arrived so I went and tested.
Results:
FC 2.4
CC .4
PH 7.6
TA 100
CYA 110

For what it's worth, pinch a penny gave me these readings yesterday
TC 4.0
FC 4.0
CC 0
PH 7.6
TA 90
CYA 90

Yesterday I took out the floater with the 3 stabilized chlorine pucks the new pool maintenance company put in as I knew I was headed in the direction that the CYA was too high. Again based on feedback here knowing it's rainy season and starting to warm up I was going to shift to doing bleach daily (or liquid chlorine) instead of the pucks to try to bring down CYA. But, I'm at a loss what is the right next step. Do I drain and refill to bring down CYA as the first next step? Do I daily add bleach while I'm draining removing and replacing some water?

Right now the water is really clear and looks good but I know that can change quickly.
 

Rancho Cost-a-Lotta

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You're on the right track...getting a good test kit was the first step. A water exchange is in your future. We just need to nail down how much.

What is your CH level?

Did you do a diluted CYA test to get the 110 result? If not, follow the directions below:
  1. Fill the mixing bottle to the lower mark with pool water.
  2. Continue filling the mixing bottle to the upper mark with tap water.
  3. Shake briefly to mix.
  4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
  5. Continue the test normally from step 2, but multiply the final result by two.
 
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ladylonghorn

Active member
Jan 14, 2016
31
Frisco, TX
Pool Size
16700
Surface
Plaster
Chlorine
Liquid Chlorine
You're on the right track...getting a good test kit was the first step. A water exchange is in your future. We just need to nail down how much.

What is your CH level?

Did you do a diluted CYA test to get the 110 result? If not, follow the directions below:
  1. Fill the mixing bottle to the lower mark with pool water.
  2. Continue filling the mixing bottle to the upper mark with tap water.
  3. Shake briefly to mix.
  4. Pour off half of the contents of the mixing bottle, so it is again filled to the lower mark.
  5. Continue the test normally from step 2, but multiply the final result by two.
CH is 345. Since I'm new to self testing, not sure what you mean diluted...I did the Free & Combined Chlorine (FAS-DPD) test and I tested with 25 ml of water.
 

Rancho Cost-a-Lotta

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not sure what you mean diluted
The diluted test is for CYA. I don't have the Taylor kit. Is there a marking on the comparator for 110 ppm? If not, follow the instructions above for the diluted CYA test. You're basically mixing the pool water sample with tap water (50/50) before adding the reagent. Complete the test and double the result shown on the comparator.
CH is 345
You can't get this result from either the 10mL or 25mL CH tests. The multiplier (of drops) for the tests are 25 or 10. You can't get 345 by multiplying either.
I did the Free & Combined Chlorine (FAS-DPD) test and I tested with 25 ml of water
This is fine, but you can conserve reagents by using a 10mL sample. Results will still provide the accuracy needed for daily maintenance. Use one scoop of powder and each drop counts as 0.5 ppm.
 
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Rancho Cost-a-Lotta

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And I mistyped, CH is 360.
Great...no issues with high CH for now. Save reagents and use the 10mL sample for future tests.

Since fill water contains no CYA, you'll need to drain 50% to get your CYA to 50 ppm, probably a good number for Texas summers. Just to account for discrepancies in testing, I would shoot for a 60% or more drain/refill. You can always add a bit of CYA or use tablets to bring your CYA back up.

Do you have a strategy in mind for draining?
 
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Flying Tivo

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Jan 24, 2017
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Monterrey, NL, Mexico
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I figured out what you meant by diluted CYA test. When I did this, my CYA reading is 100.
Please elaborate a little more. So after diluting you got 100? if so you need to multiply that by 2, which means you are at 200. Or did you mean you got 50 diluted and multiplied by 2 to get 100?
 
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ladylonghorn

Active member
Jan 14, 2016
31
Frisco, TX
Pool Size
16700
Surface
Plaster
Chlorine
Liquid Chlorine
It was 50 - - so x2 = 100.

My strategy at the moment is to do liquid bleach/chlorine exclusively and leverage the normal filling that is required due to evaporation and dilution via rainfall. I work from home so I'll be in a position to do this. I want to entirely get away from the tabs for now as suggested by others on my posts about CYA.
 
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Rancho Cost-a-Lotta

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CYA (and CH) levels do not decrease with evaporation. As clean distilled water evaporates, it leaves the solids behind. The only way to remove CYA is to exchange CYA-laden water CYA-free water. You can slowly reduce CYA through rainfall, but you would need to remove water before the rain comes. CYA does oxidize slowly, but likely not quick enough to notice in month-to-month tests. The best strategy is to replace water to lower your CYA to a more manageable level. A few hours, a submersible pump, and a place to drain the water is all you need.

You may be able to manage you pool with a high CYA level. Assuming your test result is accurate, your minimum FC level is 8 ppm according to the FC/CYA Chart. You daily target levels for FC are between 11-13 ppm. The pH test is invalid with FC levels above 10 ppm, which means you would need to check pH before adding chlorine. Dropping below the minimum level is like inviting algae over for a swim party, so you need to stay vigilant.
 

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