Drain / Fill question

[aceniza]

I can't believe I'm asking this.... I've got a lot on my plate lately so I'm going to blame that on my dumb-dumb question

Just put in a new Turbo15 salt cell. It keeps saying my salt is 5200ppm, I'm testing it at 4800ppm.
Anyhow, I need to get it to 3200-3400ppm. The Pool Math app tells me I need to drain 33%

Here's where my brain fails me.
How far down should I drain it?
I know draining too much is safer that not enough - though I can probably hit 3800ppm and still generate chlorine.
At the same time, I don't want to drain so much that refilling it is going to cost an arm and a leg.
I'm thinking approx 2' down the deep end?

 

[HermanTX]

I can't believe I'm asking this.... I've got a lot on my plate lately so I'm going to blame that on my dumb-dumb question

Just put in a new Turbo15 salt cell. It keeps saying my salt is 5200ppm, I'm testing it at 4800ppm.
Anyhow, I need to get it to 3200-3400ppm. The Pool Math app tells me I need to drain 33%

Here's where my brain fails me.
How far down should I drain it?
I know draining too much is safer that not enough - though I can probably hit 3800ppm and still generate chlorine.
At the same time, I don't want to drain so much that refilling it is going to cost an arm and a leg.
I'm thinking approx 2' down the deep end?
View attachment 447434

I would agree - 2.5 to 3 ft. Of depth. How are you testing your salt Level?

 

[aceniza]

I would agree - 2.5 to 3 ft. Of depth. How are you testing your salt Level?

just by taste
j/k.... taylor k-1766 i believe?
When trying to recalibrate my Aquarite says 5200 and then goes to 0 without ever hitting 4800.

 

[mknauss]

Be careful with a fiberglass pool and draining. They can pop out of the ground pretty easily if you have ground water or saturated soil.

 

[aceniza]

Be careful with a fiberglass pool and draining. They can pop out of the ground pretty easily if you have ground water or saturated soil.

thanks. We do have a drain to pull the water out from underneath, but I didn't use it. We've had 1 storm in almost 2 months, which is somewhat rare for North Texas. Our earth is dryyyyyyyy right now. Last month I was losing about 4" to evaporation almost twice a week.
Our normal water bill of $170-200 was $370 last month!

 

[duraleigh]

8" of loss over a week period is a leak......not evaporation.

 

[aceniza]

8" of loss over a week period is a leak......not evaporation.

That's what I was worried about - however my neighbors were experiencing the same thing, and it has halted since the weather cooled off

 

[aceniza]

Be careful with a fiberglass pool and draining. They can pop out of the ground pretty easily if you have ground water or saturated soil.

you got me paranoid now. I have 1200sq ft of concrete that I would rather not get destroyed, and the plumbing as well.
I'm draining from the deep end, and filling from the spa/shallow side.
I'm sure it'll take much much longer now, but $200 more on my water bill is better than thousands to repair my deck and plumbing if that pool starts to rise.

 

[mknauss]

Did you do the calculation on which way to exchange shown on Draining - Further Reading

 

[aceniza]

Did you do the calculation on which way to exchange shown on Draining - Further Reading

I did not - but luckily everything checks out. Thank you!

 

[Tcadwall0]

you got me paranoid now. I have 1200sq ft of concrete that I would rather not get destroyed, and the plumbing as well.

Yeah - besides the possibility of floating, the backfill pressure and the water pressure equal each other out, so it isn't just popping you have to worry about. Bowing would be likely as big of a concern. This is why they backfill at the same rate they fill for FG pools.

 

[aceniza]

So this has been a major PITA… this whole year actually.

Salt was 4800 tested with K-1766
Drained 1/3 and refilled per Pool Math

Now hayward is saying 800ppm and testing is 1000ppm.

Running the pump for a few hours (refilled over night) and will retest.