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PKGuy

PKGuy

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May 3, 2012
20
Hello.
I have had my pool for about 6 years now and have always relied on the pool store to sell me what I needed (or what they told me I needed.)
Just opened it up today -- water looked really good. Used the TF100 and came up with this:
chlorine = 0
PH = 7.5
TA = 180
CH = 310
CYA = 100 ish

Using the pool calculator and what I read in Pool School, I had some left over PH Reducer (dry) and added one pound, turned the return up to break the surface to reduce the TA. Then I put in 96oz of 6% Great Value bleach, which should have gotten me to a chlorine of 7 -- but I'm not really sure if I'm using the pool caclulator correctly.
I remeasured the chlorine and PH and got: 2 and 7.2

Looks like I going in the right direction, yes or no?

Jim
 
The first decision you have to make is are you going to try to live with high CYA or as we will recommend, lower it to be manageable.

Try doing the CYA test with a 50/50 mix of pool and tap water then double the results to gave a better feel for your true level. Then you may want to replace water to get down to 30-50ppm.

Adding any chemicals now if you need to replace water is just a waste.

Posted with Tapatalk ... sorry if I sound short ... hate typing on phone :)
 
Hi, Jim,

Welcome to the forum. :lol: Like Jason said, your CYA is too high. I feel even stronger that you will be unable to manage your pool until you get CYA down around 50ppm, which will involve at least one partial drain/refill.
 
So what does "living with the high CYA" entail? Adding chlorine more often? Keeping it at a higher level?

The CYA/chlorine chart says my chlorine level should be between 7 and 12 with CYA at 100. If I choose not to do a 40% drain and refill ($$$) what negatives am I really looking at? Any health issues?
 
The standard CYA test will report any CYA level over 100 as 100. Your actual CYA level could be much higher than 100. You can narrow this down by doing the test with dilution, as jblizzle suggested.

If CYA is actually right near 100 you can kind of get away with it, but all kinds of things get more complicated and if you do get algae it is more or less hopeless to try and kill the algae. The simple part is that FC needs to be higher. One challenge is that the PH test doesn't work correctly when FC is above 10, which it is likely to be. Routine chlorine testing takes way more drops and gets tedious. It gets very difficult to know what your CYA level actually is, since the test doesn't distinguish anything over 90 and testing with dilution throws away most of your precision.
 
I was able to manage last season with a CYA of 90-95. After draining and refilling during closing/opening I'm now at about 60.

It took quite a bit of chlorine, especially bringing it up to shock level when I closed. On sunny days when it was getting use I could lose around 3-4ppm of FC/day.

I targeted 11, prepping for sunny days I would take it up to 14-15ppm FC.

I've always used the target as my minimum, that way if I'm off it has a bit of room before hitting the minimum too soon.

Note: I would have to double check, but I'm thinking the water to fill during opening was $30 or less (for me, ~3400 gallons). My chlorine costs were probably around 30% higher than they've been so far this year.
 
PKGuy said:
Hello.
I have had my pool for about 6 years now and have always relied on the pool store to sell me what I needed (or what they told me I needed.)
Just opened it up today -- water looked really good. Used the TF100 and came up with this:
chlorine = 0
PH = 7.5
TA = 180
CH = 310
CYA = 100 ish

Using the pool calculator and what I read in Pool School, I had some left over PH Reducer (dry) and added one pound, turned the return up to break the surface to reduce the TA. Then I put in 96oz of 6% Great Value bleach, which should have gotten me to a chlorine of 7 -- but I'm not really sure if I'm using the pool caclulator correctly.
I remeasured the chlorine and PH and got: 2 and 7.2

Looks like I going in the right direction, yes or no?

Jim
Click to expand...
Just a note, but my pool is half your size. I only have 30-40ppm CYA. To go from zero FC to FOUR...I need 50oz of 6% bleach. So I think your math is off a bit - you shouldn't be able to get to FC 7 in a 12kgal pool with 96oz of 6% bleach, especially at 100+ CYA.

As everyone else has recommended, you need at least a partial drain and fill, but only after you find out for sure what your CYA is at.

Then, I recommend you use http://poolcalculator.com and make sure you enter your numbers properly. This has unerringly told me the right amounts (which I've verified many times with before and after testing).

GL!
 
Thanks for all the "real world" insights! My knee-jerk reaction to a partial drain/refill is due to our water department's notorious billing practices. We get billed by the MCF which equals 7500 gallons. My d/r would be about 5000 gallons to get me to a CYA of 60. So the water would cost $41.50 (at $55.14/MCF) and the associated sewer charge would be $36 for a total of $77.50.

Is the consensus that it would be worth it?
 

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Note too that many water companies will not charge you the sewer fees if you are filling a pool
... assuming you are not draining it into the sewer.

You can call and tell then what you are doing and they may adjust the bill.

Posted with Tapatalk ... sorry if I sound short ... hate typing on phone :)
 
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