Still learning... please help

[Jaredsdad]

Drained pool (most of it) Wednesday. Was full Thursday morning. Let pump run all day yesterday. I came home and tested CYA. 20 or below. FC was 2.5. I brought it to 4 yesterday evening around 6pm.

Tested this am, it was at 3.5.
Tested this evening, around 6 (24 hours later) and it was at 1.6. I took it back to 4.

Other specifics: Weather today was sunny. 84. Direct sun. Water running through solar panel.

Seems like a lot of FC to lose in 24 hours. Or maybe not. Is this normal?

 

[Richard320]

That sounds pretty normal for such low CYA. The half-life of FC in sunlight at 20 CYA is about 5 hours.

 

[Mjman15]

^^^^Agree, normal for that cya

 

[Jaredsdad]

Perfect! Thank you! I'm gonna bump the CYA some. To 30 or so and hope it stays there.
As for the FC I'm hoping to get into a groove where I pretty much know how much liquid 10% to pour in every evening.
2 nights so far, I'm keeping records!

- - - Updated - - -

Higher cya will make it stay around a little longer??

 

[Richard320]

Perfect! Thank you! I'm gonna bump the CYA some. To 30 or so and hope it stays there.
As for the FC I'm hoping to get into a groove where I pretty much know how much liquid 10% to pour in every evening.
2 nights so far, I'm keeping records!

- - - Updated - - -

Higher cya will make it stay around a little longer??

Yes. Personally, I'd target 40-50 CYA.

You are correct -- you will learn your pool's appetite in just a few weeks and be able to predict your test results with amazing accuracy before the first droplet leaves the bottle. That's when pool care becomes as mindless and routine as brushing your teeth.

 

[Jimrahbe]

Jared,

Yes, higher CYA will keep it around a little longer.

Most pools use 2 to 4 ppm of FC per day.

In a few days you will get a "feel" for what your pool needs..

Thanks,

Jim R.

 

[Jaredsdad]

The next problem I have is CYA. I drained pool. My k2006 only reads down to 30.
I filled the test tube all the way and could still see the black dot. That's why im saying 20. But it could be zero for all I know. I guess I could assume 20, add stabilizer to go to 40, and then test again

 

[Richard320]

The next problem I have is CYA. I drained pool. My k2006 only reads down to 30.
I filled the test tube all the way and could still see the black dot. That's why im saying 20. But it could be zero for all I know. I guess I could assume 20, add stabilizer to go to 40, and then test again

CYA isn't in tap water, so unless you added some to your pool, you have none. Dichlor and trichlor "shock" and pucks add some, but if you haven't been dumping in bags of stuff, it's safe to call it zero.

 

[Jaredsdad]

No I am only using liquid chlorine! Learned that from here.
I didn't drain all 10,000 gallons, I'm guessing I drained 7-8,000 gallons. Apparently little TOO much to hit my target. I was at 180 cya, pool math said drain 6800 gallons. I must have went a little over. Hard to tell once the shallow end is empty.

 

[Richard320]

No I am only using liquid chlorine! Learned that from here.
I didn't drain all 10,000 gallons, I'm guessing I drained 7-8,000 gallons. Apparently little TOO much to hit my target. I was at 180 cya, pool math said drain 6800 gallons. I must have went a little over. Hard to tell once the shallow end is empty.

Then call it 20 and work up to your target. You can always add more later if you come up short. You've seen how much of a pain it is to lower CYA.

 

[Jaredsdad]

Yes... it was. But less painful than spending $70 on granules that may or may not work in 2 weeks!