More questions on CYA

[bhubb]

A month ago (i opened our new pool - old pool - new to us)i tested my CYA at 100+.. I drained 50% and it was down to 80s.

i got a wonderful green pool now so i drained more than 50% and refilled and started the SLAM

i tested CYA again and it is 100+

does algae or slam affect cya?

how in the world did it go up? Even if i was at 200 initially i should be lower than 50 now!

my autofeeder is empty and i use no products other than "splash pool shock" 12.5% sodium hypochlorite liquid chlorinator and regular household bleach

 

[jblizzle]

Fill the tube with straight pool water. If the dot is still clearly visible, then the test result would not be impacted by the green.

Lighting is pretty important for the CYA test ... were all tests done the same?

I can only guess that one or more of the tests you did were done in error somehow.

 

[bhubb]

Fill the tube with straight pool water. If the dot is still clearly visible, then the test result would not be impacted by the green.

Lighting is pretty important for the CYA test ... were all tests done the same?

I can only guess that one or more of the tests you did were done in error somehow.

pool water in tube is easily clear. I am doing outside with back to sun. It is overcast some now. Would that play that big of role?

without an accurate reading i am confused on the FClevel i need to maintain for slam process

 

[jblizzle]

Some clouds would not account for the difference between <50 (as expected) and >100 as you are reading.

I think lighting should only impact it by +/- 10-20ppm

 

[bhubb]

If i treat my pool like 80 CYA and slam according to the chart will it hurt if cya is actually in 50s?

 

[jblizzle]

I would always trust the latest test. Try it again, pour back and forth a few times to see if you are consistent.

 

[bhubb]

Bright and sunny day today. Tested cya twice and both times it is at 100.. This is insane seeing as i have done 2 partial drains and refills.

at this point i am about to fill this thing in with dirt and live a happier life

i dont see how this is user error. I have watched several videos of people doing this test and i am doing it exactly like them

edit: poured back and forth SEVEN times and right at 100 everytime

 

[bhubb]

Ok did the dilution method and got to 50ppm so i am assuming my cya is right at 100. I guess a drain and refill is what i will be doing this holiday weekend

 

[DorsalSpine]

Ok did the dilution method and got to 50ppm so i am assuming my cya is right at 100. I guess a drain and refill is what i will be doing this holiday weekend

Keep in mind with the dilution method you are increasing the error factor of an already subjective test. My experience with a 200+ CYA was I couldn't get a really accurate reading until I got it well under 100. Drain and refill will get you there.

 

[bhubb]

Keep in mind with the dilution method you are increasing the error factor of an already subjective test. My experience with a 200+ CYA was I couldn't get a really accurate reading until I got it well under 100. Drain and refill will get you there.

I am thinking this cya was in the high 300s.. I went back and looked at pool store readings that they took it to and they recommend anything less than 400 so the previous owners probably were fine with their 350-400 cya. I am draining and refilling now and will report back

i am draining and filling from 2 hoses so will let it go for a few hours and retest tomorrow since it is supposed to be sunny