A little confused by Pool Math

[makeupanameforme]

I’m brand new to pool ownership. Inherited a pool 4 days ago with zero FC and zero CYA.

~45,000 in ground concrete pool, non SWG.

Pool Math told me to target 3 for FC so I started working toward that with SLAM. It also told me I needed to add 6 gallons of stabilizer. Now, after several shocks and adding the 6 gallons of stabilizer, I reached the target of 3 FC and have 70 CYA. Well now when I check targets in Pool Math it tells me I have a new target of 8 FC and my CYA is too high and needs to lower to 45.

Pool store test kit says all my current levels are in the OK/ideal range. I understand those are old thinking and plan to work toward Pool Math targets but I have a few questions.

1. Why would Pool Math tell me to target 3 FC but also at the same time tell me to add 6 gallons to raise CYA to a level that’s too high and would also then require a higher FC target?

2. Again, I’ll work toward what Pool Math says but since the pool is in OK/ideal range according to the test kit I assume it’s at least okay to get into at this point, is that correct?

3. Since my CYA is too high, should I focus on removing some water from the pool and adding fresh water to lower that first (which I assume will lower the target FC a bit)? Or should I focus on reaching the 8 on FC first?

Appreciate the help!

 

[Texas Splash]

Welcome to TFP! The PoolMath APP is a great tool, but it may not always understand your exact situation. So for that, it's best to share your test results here first, especially as a new member so we can walk through a few things. So before you do anything else, please post a full set of test results. Also confirm which test kit you are using. You can add that to your signature as well.

If you didn't know, in your APP settings there is an option to share test logs here to your TFP profile. That way we can see them at any time as needed.

If your FC is indeed low, you should add some liquid chlorine, probably about 5 ppm worth for now, until we can review your test numbers.

Also bookmark -----> Pool Care Basics

 

[ajw22]

1. Why would Pool Math tell me to target 3 FC but also at the same time tell me to add 6 gallons to raise CYA to a level that’s too high and would also then require a higher FC target?

PoolMath is just a calculator. MY guess is the 3 FC recommendation was based on having 0 CYA entered. PoolMath only knows what is entered and not what you need.

2. Again, I’ll work toward what Pool Math says but since the pool is in OK/ideal range according to the test kit I assume it’s at least okay to get into at this point, is that correct?

Work towards...

What Are My Ideal Pool Levels?

Use our tool to find ideal chemical levels for any swimming pool. Check TFP recommended levels on pH, free chlorine, cyanuric acid, and more.

www.troublefreepool.com

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

Use PoolMath as a tool to calculate how to get there.

3. Since my CYA is too high, should I focus on removing some water from the pool and adding fresh water to lower that first (which I assume will lower the target FC a bit)? Or should I focus on reaching the 8 on FC first?

Your CYA is manageable. Let it degrade over time. Keep your FC at 8-9.

 

[Bperry]

The default FC target that poolmath fills in is 3ppm when the CYA value is anywhere between 0 and 50ppm. But that target is not poolmath telling you that 3ppm is the correct target, it just puts it there as a default expecting the user to adjust it to the target they actually want.

I’m not sure how it chooses that default value, but maybe changing the default target value to be the middle of the range thats listed would be a better default.

 

[Mdragger88]

You mentioned Slam -
That is a higher fc level- not maintenance levels as you posted.
Do you have visible algae or cloudy water or a reason to do the
SLAM Process? In poolmath there is a slider to turn on for slam. The fc values shown in poolmath are based upon your cya input. You can adjust the target value at anytime to suit your needs. There are ranges shown to help with that decision. As mentioned, its just a calculator.

 

[makeupanameforme]

Thanks all, great tips. I know I have a lot to learn and I'm reading and watching videos every day, just trying to get things to good level quick so I don't end up with a bigger problem in a week or two. I've added 3 gallons of liquid chlorine like recommended with the hopes of getting to a good target FC. I've also ordered one of the recommended test kits which will get here tomorrow. Looking forward to learning more from you all!