partial drain/refill technique to lower CYA

[evanbone]

So I am attempting to convert to the BBB method with my pool. The previous owners used trichlor so the CYA is measuring over 100(about 60 with the 1/2 pool 1/2 tap technique). I guess I will go ahead and do a partial drain/refill and I am looking for suggestions on how. I do have an L shaped pool so I was considering putting the hose in the shallow end and draining exclusive from the bottom drain in the deep end.
Question- will the new water sit on top of the old water or does it depend on the temperature of each? Should I get my chlorine real high and stop the water circulation to attempt this? Is there a better suggestion in general?

 

[JasonLion]

I wouldn't worry about the water mixing or not mixing too much, it will still work either way.

The other option is a little more complex, but uses slightly less total water. That would be by draining 18" and then refilling, and repeating a couple of times. However to do that you need to be able to draw water from only the main drain, otherwise you will lose prime.

 

[evanbone]

and when you say "main drain", that's the bottom one?

 

[frustratedpoolmom]

Yes

 

[evanbone]

The other option is a little more complex, but uses slightly less total water. That would be by draining 18" and then refilling, and repeating a couple of times. However to do that you need to be able to draw water from only the main drain, otherwise you will lose prime.

So why out of curiosity would I just do 18" at a time instead of doing it all in one whack?

 

[jblizzle]

Because it can be a bad idea to drain a liner pool ... it may shift or be damaged.

 

[evanbone]

ok, that makes perfect sense. thanks