How low can i safely drain my vinyl pool

[tim86]

I need to partly drain my vinyl pool due to cya being at 90, the liner is 5 years old ruffly and dont know exact thickness but know about as thick as u can buy, least thickness of a dime, its 3 feet on shallow end and 6 on deep end, 24 feet long by 14 feet wide. have to drain it slowly with sump pump with 100 foot hose due to no bottom drain so going take awhile and get to about 60 degrees at night and may not be able fill it back till tomorrow, but to get cya down need drain least half, doubt ill get that much but want drain as much as safely possible and if needed redrain once refill to delute it more

 

[jblizzle]

You should leave at least 1 foot of water in the shallow end. So sounds like you should be able to drain about 2 feet which is likely ~50% of the volume.

 

[tim86]

and if cya is at 90, should drop to 45, what would u recommend for cya level, theres trees above the pool and i run pump 24/7, i know higher cya u need higher free chlorine, but at same time u lose less chlorine daily, pool gets average sun light at best

 

[jblizzle]

Replacing 50% of the water would lower the CYA by 50%.

45ppm would be tolerable. Yes the FC ppm number is higher, but you actually lose less to the sun.

Also, there is no need to be running the pump 24/7 ... just a waste of power.

 

[tim86]

what would u recommend highest level i let my cya stay without causing other major issues, got high due to auto chlorinater which im not going to use anymore, and with pump i have a single return and skimmer and thats it, no bottom drain or extra returns, and around here electric isnt high so at most running pump all day costs me 60-80 month extra, and with 2 large trees from neighbor directly above pool if dont run it top pool gets dirty quick, so the extra 60 is worth never having to clean top of pool

 

[jblizzle]

You could make 90ppm work without much effort ... assuming your water is clear and you do not need to follow the SLAM process.

There really is no "highest level" as long as you keep the FC at the right level based on the [FC/CYA][/FC/CYA].
One issue that pops up if the CYA is too high, then you have to maintain the FC above 10ppm which makes the pH test artificially high ... so you never get a good reading.

 

[tim86]

with only one return, and one skimmer, skimmer on one end and return on shallow end, both on same wall, and no bottom drain, how long do u think should run pump daily to keep it clean, pool is 24 x 14 ruffly 11k gallons, and pump is a 1hp hayward, only one speed

- - - Updated - - -

renting house atm and plan on buying but starting to debate, not much normal work for pool, that its old design with single return and skimmer, but also top poool step is cracked bad, patched but eventuly have replace and worst part is neigbors tree roots have grown under vinyl floor of pool,

 

[jblizzle]

You probably only need 2-4 hours to circulate the chemistry. But, you may need to increase the run time to suit your desire of keeping the debris out.

 

[tim86]

and i know only a guess, but with tree roots, and main one maybe 1/2 inch wide and runs 15 feet or so, with liner being 5 years old and roots probley been there for years would u think any risk of them punchering liner anytime soon or probley just keep growing down and just have take care it when do replace liner

 

[jblizzle]

I have no idea ... no experience with tree roots or vinyl pools.

I would guess that the root will not likely change direction and puncture the liner. But, the liner is more likely to be damages there from activity in the pool.