Beginner: trying to balance in the fall

[Pool22H]

Should I drain water to decrease my CYA? It’s at 100. I went with the recommended amount when I added it last week and now it’s too high. (I added MA to lower my pH/TA.)

We’ve had a hurricane, a 14yr olds birthday party, & have started using the spa since the temp has dropped.

We’ve only had water in the pool about 2 months so I’m still just trying to get my basic levels correct.

All advice is welcome.

 

[Texas Splash]

Exchanging some water? .... ideally yes. A CYA of 90 or more is more difficult to manage per the FC/CYA Levels. By chance did you do a diluted CYA test to confirm the CYA is only 100? If you aren't sure about a diluted CYA test let us know and we'll guide you.

 

[Pool22H]

Exchanging some water? .... ideally yes. A CYA of 90 or more is more difficult to manage per the FC/CYA Levels. By chance did you do a diluted CYA test to confirm the CYA is only 100? If you aren't sure about a diluted CYA test let us know and we'll guide you.

I don’t know what a diluted CYA test is but I did the one that came with my testing kit… where you mix pool water & a chemical & pour it in a tube until the dot ‘disappears.’ If there’s another test to purchase, let me know.
Thanks for your help!

 

[PoolStored]

I don’t know what a diluted CYA test is

Diluted CYA test:
Add pool water to bottom of sticker or lower line in the mixing bottle.
Add tap water to top of sticker or upper line in the mixing bottle.
Shake.
Pour out half so mixture is to bottom of sticker or lower line.
Add reagent to top of sticker or upper line.
Shake.
Test outside with back to sun and tube at waist level.
Pour back and forth a few times to see if you get the same result.
Double the result.

 

[Newdude]

The key is to know how much to drain/exchange the first time. Draining 50% twice does not equal 100% because the second round also dumps half of your 'good' water. It becomes increasingly inefficient with each subsequent round so it's best to have an accurate target before you begin.