Trying to master the pool math and failed

[Jroyal]

My 27000 gal vinyl pool was opened one week ago and the water has started eating my chlorine. I had this issue last year and ended up using way to much LC I think. My current #'s are below. Can someone advise how many gal of 10% or 12.5 LC I need to purchase to go thru a slam process? Thanks in advance from newbie JRoy
FC 0.5
CC 0.5
PH 6.8
TA 90
CYA 55

 

[Texas Splash]

Welcome to TFP! The amount of chlorine needed to sustain a SLAM Process though completion can vary quite a bit based on the water's condition. Your CYA would be considered 60, so the SLAM FC level is 24. In your 27K pool it takes 6.5 gallons of 10% to go from zero to 24. From there, it's a matter of maintaining the FC level as best as you can as it drops during the day. You'll need a good 10-15 gallons to start with.

Are you sure about that pH? That's definitely too low. I would get it to 7.0-7.2 before starting the SLAM.

 

[wireform]

Jroyal,
Hi and welcome. Firstly you need to set up your signature as I have below my post. Use my link below as we don't know anything about your pool to help you figure it out.
Pool Care Basics
SLAM Process
Test Kits Compared
FC/CYA Levels
PoolMath
Overnight Chlorine Loss Test

 

[Texas Splash]

Please take a moment to update your signature with all of your pool and equipment info. See my sig as an example. It helps tremendously with replies.

 

[Jroyal]

Thanks, I will set that up asap. I'm going to rerun my #'s and confirm the PH

 

[Jroyal]

Please take a moment to update your signature with all of your pool and equipment info. See my sig as an example. It helps tremendously with replies.

Reran #'s and as follows; I picked up some soda wash 3.7 lbs to increase the PH but havent put anything in as of yet
FC 1.7
CC 1.9
PH 7.2
TA 91
CH 172
CYA 70

 

[Texas Splash]

Your pH is perfect to begin the SLAM Process. All you have to do is increase the FC to the level of 28 as seen on the FC/CYA Levels. Follow that page and you should do well. Any questions?

 

[Jroyal]

Thanks, Texas! appreciate the prompt response!

 

[proavia]

In order to measure the higher FC readings required by the SLAM Process you will need a FAS-DPD test kit. The Taylor K-1515 will meet that need. Or order a TF-Pro test kit from TFTestkits. The TF-Pro includes everything you need in a test kit and the stirrer device is included.