Chlorine depleting fast!

[TomS125]

First, thanks to all of you for your help. Your dedication to us newbies just amazes me and is certainly appreciated.

KurtV, I have Ben's 234 test kit and have run the test 3 times already. It is hard to read but black dot seemed to completely disappear at the 40 mark both times. I learned of the whole CYA thing after taking over from previous owner and continuing with Tri-Chlor pucks. The refills have seemed to do their trick after being so high last July and having an algae bloom with CL levels where I had always had them.

I suspect it is working on something but the water is so clear right now that even that didn't seem to make sense. I can literally make out every screw head on the drain at the 8' deep end. Does it make sense to have that much for Cl to be working on with this water clarity? Also, when I measured Cl over last weekend, I found no CC with Ben's kit. It didn't seem to be the issue but UV didn't seem to add up either with CYA where it is at. I was thinking like Janet that I need to add it back now.

[KurtV]

First, thanks to all of you for your help. Your dedication to us newbies just amazes me and is certainly appreciated.

KurtV, I have Ben's 234 test kit and have run the test 3 times already. It is hard to read but black dot seemed to completely disappear at the 40 mark both times. I learned of the whole CYA thing after taking over from previous owner and continuing with Tri-Chlor pucks. The refills have seemed to do their trick after being so high last July and having an algae bloom with CL levels where I had always had them.
So, I think it's pretty safe to rule out that theory.

I suspect it is working on something but the water is so clear right now that even that didn't seem to make sense. I can literally make out every screw head on the drain at the 8' deep end. Does it make sense to have that much for Cl to be working on with this water clarity?
Not to me, but I can't think of anything else.

Also, when I measured Cl over last weekend, I found no CC with Ben's kit.
Yeah, the no CC argues against my second theory, but I don't think it rules it out.

...but UV didn't seem to add up either with CYA where it is at.
Agreed. UV can't be causing that much chlorine loss with that level of CYA (unless maybe you live at the equator).

I was thinking like Janet that I need to add it back now.
I'd really hesitate to raise CYA. Many people here are holding chlorine in their pools for a reasonable amount of time at even lower levels of CYA and you know better than I what a pain it is to get it back down. Where do you live, by the way?

I'd still give shocking a try (think Occam's razor).

[TomS125]

I'm in greater St. Louis area. We have just started to get some sun and warmer temps - not sure of water temp but imagine it is high 60's - still too cool for the kids!

Sounds like shocking is the answer to see if I can get it to begin holding.

[TomS125]

An update....I think my CYA measurement is off. Despite doing it twice and reading 40, I have to think it's more like 20. Chlorine is still disappearing fast but only during the day and I'm not showing any CC when I do have chlorine in there. After adding bleach and testing chlorine reading last night, it held the same reading this morning. Then it will be gone by the time I get home this evening.

I know I need to get more CYA in now but with the difficulty in knowing exactly where I'm at now, I'm not sure how much to add. I'm thinking about using pucks for a few days to try to maintain some consistent chlorine during the day while I'm at work and bring CYA up slowly until I see it holding. Thoughts?

[KurtV]

Tom,
Do you have a local pool store that you have any confidence in where you can have the water tested? Even better would be a couple of pool stores so that you could compare their results against each other and against your test.

I wouldn't use any pucks until you know your CYA level to a reasonable certainty and accuracy.

[aylad]

If you decide to use the pucks, keep an eye on your pH--the pucks will tend to lower it, and yours is low already...

Janet

[TomS125]

Wait, I thought the pucks will increase CYA?

[rhosk]

Edited (deleted) for clarity.

[aylad]

Ah, thanks for catching that, I've already corrected the post. What I meant was to watch your pH--the pucks DO lower that--and yes, they raise your CYA. Sorry--I worked last night and apparently haven't slept enough!!

Janet