PoolMath Question

[TrampledUF]

So with a CYA of 60, I wanted to raise my FC from 1 to 8. PoolMath said to add 29oz of cal-hypo 73%.
Then just for kicks, I set CYA to zero, and it said for that case, I would only need 9.6oz.

Is that right? I understand why you want higher FC when CYA is high, but I wouldn't think it would take any more chlorine to GET to a certain level.

I'm just looking for someone to tell me this makes sense, so I don't worry that PoolMath is wrong. If anyone also knows WHY this is the case, even better.

 

[Richard320]

Is this with the app or the webpage?

On the webpage. 26000 gallons, 1 FC to 8 FC calls for 34 oz by weight of 73% cal-hypo, regardless of any other value.

So you input something wrong -- maybe fat fingers on a small phone keyboard -- or there's a glitch with the app.

 

[mknauss]

I checked on the app. Same 34oz of 73% cal hypo.

 

[AUSpool]

I get 9.6oz regardless of the CYA. Are you sure the first 29oz wasn’t for slam level?

Edit. I didn’t change the volume and got 9.6oz, how random, although that was for volume. The other question is what Cal-hypo, be aware that it has calcium and will raise your CH.

 

[TrampledUF]

Seems to be a glitch in the app (@Leebo FYI). It works properly as long as the last value I change is the Target FC. (Android)

In any case, I added the right amount. Thanks everyone.

P.S. I know that cal-hypo raises CH, but in my experience, using cal-hypo, it takes a couple years to get too-high CH, and only a couple months of tri-chlor pucks to get too-high CYA.

 

[jblizzle]

Which is why in TX we would recommend the use of liquid chlorine or a SWG .... then you do not have the CYA rising problem or increase the CH climb that will happen just from your top-off water.