vinyl pool, how far can i drain?

[xycosse]

Long story short, I hired someone to take care of my in-ground pool for a while which was a mistake, and now my CYA levels are off the charts (I'd guess 160? Neither test kit I have goes past 100). Being afraid to drain the water too low in my vinyl pool, I drained probably 6 inches out and refilled it back up three times. Not making a big dent in my CYA issue....

How far down can I drain the water in a vinyl pool without risking damaging or insetting the liner? I'd like to drain out about half and refill, but even a couple feet would be a lot better than my 6 inches at a time. I'm afraid of my water bill already.

I have a new SWG being delivered tomorrow, so I'm trying to get my CYA levels in range before I put in my pool salt.

 

[sgoosman]

You should leave a minimum of 12 inches in the shallowest part of the pool. You need to keep weight on the liner ensuring the liner does not shift or shrink. Additional liner age can impact the liner, if old you may want to be conservative and leave a little extra. High water table can be an additional problem, forming water bubbles without the weight and force. Unlikely to be an issue on the shallow end but be aware and pump out a dry well if you have one prior to draining.

You should be able to drain more than 6 inches at a time although depending on your water costs renting an room system may be more cost effective alternative.

 

[ajw22]

See step 8 in CYA - Cyanuric Acid Test - Trouble Free Pool to do the dilution test when your CYA is over 80.

@mknauss can provide a water exchange method.

 

[borjis]

I had to do a water exchange.
Don't like draining down at all except for a few inches since my newish liner was a very tight fit...don't want to stress it.

With the pool pump off the entire time:
I ran a small sub-pump in the skimmer to my gutter drain.
At the same time that was emptying, I put a garden hose down on the deep end floor,
on the opposite side of the pool.

Just ran the hose full bore and the drain pump for roughly 8hrs a day for 2 days.
It was good to go after that. You might need to add another day or two worth of exchange....maybe.

They key is keeping the replacement water as separate or far away from as the skimmer water.
Some have mentioned warmer/colder water having an effect. My tap water was not really
much different than the pool water temp and it was still sufficient for a successful exchange.