CYA - broadcast and brushed like crazy. Is it dissolved? Or stuck in filter?

[singerteacher]

So, we have pollen in the pool after every rain. We've got a method for dealing with it: add DE to our sand filter, vacuum up the little pollen puddles, and backwash the filter.

However, due to all the pollen and backwashing in June, the pool is now low in CYA. I would usually add it in a sock, hang in front of a skimmer, and wait. But, we're leaving for a few days, and I wanted to solve the CYA issue, since I won't be able to adjust the chlorine level for a few days.

So, I broadcast CYA into the pool last night, and brushed for 30 minutes until it seemed to be dissolved. I did this instead of the sock because I wanted to be able to vacuum/backwash the pollen before we left. This morning, there was a small pile of CYA on the bottom, which I brushed until it dissolved.

I think we should be good to vacuum/backwash. But, now I'm worried that instead of dissolving, the CYA just deposited itself in the filter, and I'll backwash it all out again.

Questions for the experts:

Would the CYA be visible in the backwash water?

Would the DE in the filter make it harder for CYA to recirculate?

 

[ping]

I think you will find out what happened to the CYA in about a week. Whatever you do don't add more for at least a week to make sure all the CYA has dissolved and is readable on a test.

Once solid CYA is in the filter it just needs time to dissolve and there's no telling on how long it will take to dissolve. I experimented by adding granular CYA straight to the filter and it took almost two weeks to fully register on a test.

It would be difficult to see the CYA in the backwash water.