Questions about timing a pool drain

[Pamofferman]

Hello!

We bought a house with a pool in early June, and I've slowly been educating myself on taking care of the pool through the many resources on this site.

The previous owners had a pool service that strictly used pucks through a DekChlor thing. I quickly stopped this and have only used LC and MA since taking over, but I inherited a sky high CYA and CH numbers.

Full test results from this am:

FC - 9.0
PH - 7.8 (treated with MA per PoolMath)
TA - 90
CH - 480
CYA - 100

I've known for a while that I need to drain. My pool is plaster. It's small and doesn't have a deep end, more like a slightly deeper area in the middle, only about 5' so I'm uncertain that the sub pump out, hose water in technique I've read about here will work. Add to this temps here in AZ are regularly over 100 and water is crazy expensive.

I don't love maintaining such a high FC but keep procrastinating on figuring out how to drain.

I'd love any thoughts or advice.

 

[Rancho Cost-a-Lotta]

No algae...No hurry. Just try to test when FC levels are lowest so your pH test is not skewed by high FC. I'm managing a CYA of 120 and CH of 700 in a slightly cooler climate. I have some challenges to draining so I may need to step up and pay the $600+ for reverse osmosis. Just keep an eye on your CSI and try to keep it slightly negative to avoid scaling. You won't save any money on chlorine by maintaining a lower CYA level...unless you need to SLAM.

 

[mknauss]

With a CH of only 480 you do not need to drain immediately. Use PoolMath to monitor CSI. Keep it between -0.6 and 0.3.

Did you get your CYA using the dilute test? If not, do Step 8 in Pool School - CYA

With our high pool water temperatures and if you maintain your FC at 7.5% or higher of your CYA, your CYA will drop some over the next couple months. You should be able to manage this.

What is your fill water CH and TA?

 

[Pamofferman]

I did not use the dilute test, although I’ve read about it. I was saving it for when I have locked into a plan to drain.

My fill water TA is 120, CH is 220.

Rancho, thanks for the helpful words. I appreciate knowing what to check for!

 

[mknauss]

If your pool water CH is 480 and fill water is 220, your pool was just drained refilled in the last 6 months to a year.

I would do the dilute test now. Because if you are near 100 on the CYA, you can manage this and the CYA will drop and you can delay a complete drain until fall 2019 I would suspect.

 

[Pamofferman]

Wow. That is so interesting. I ran so many CYA tests trying to get it right that I had to order a refill. I think it arrives tomorrow. I’ll get on the dilute test ASAP. Thanks!