Keep adding chlorine

[Jd-underdog]

I seem to be adding about 2 gallons of shock per day. I just tested my water with the tft test kit. Here is where I am at

Fc 0

Ph 7.8

Ta 130

Cya 40

Have a 40,000 gallon liner I ground pool. I added 2 gallons of liquid shock 10%
And when I test it again tomorrow the fc will be zero. Should I have to add 2 gallons of shock everyday? Pool has been open for about a week and no one has been in it yet? Also wondering how often sand should be changed in sand filter? Anyway to know when it’s time to change? Could that be my problem? The sand in the filter is at least 7 years old
Thanks for the help
John

 

[Donldson]

That's not a normal loss, sounds like you have something growing. The solution to that is to SLAM Process the pool. That will get rid of whatever is growing and get your daily FC demand under control.

Sand should never need changed. You may want to pop the top off of it and try a deep clean to get any gunk out that is hiding in there, but the sand itself should be just fine.

 

[Jd-underdog]

Is it normal to slam a pool once a year?

 

[Donldson]

If you close your pool in the winter it is not unusual to need to SLAM after opening.