Understanding CSI and FC in Pool Math

[Captain 776]

Did a full range of tests, pretty much balanced just calls for
23 oz by weight of PH Minus
120 oz by weight of baking soda

I don't really understand the CSI and FC portion of Pool Math. Please comment, are these values OK?

 

[setsailsoon]

Captain,

I couldn't see all of your results. CSI looks good to me - just needs to be between .6 and -.6. This section gives you a new target based on your other test results. FC in the section you posted is a recommended range for you based on your current CYA as well as treatment levels for algae blooms.

Remember to make changes gradually except for FC.

Does this help?


Chris

 

[xyz]

So I'm guessing from PMs FC recommendations that your CYA is below TFPs recommendation for CYA.

Also, what I found is you can play with the "Now" and "Target" values and see what changes. For example, up your CYA to 80 in PM and see what happens to the recommended FC levels.

Lower your pH and see what happens to CSI.

 

[pooldv]

Good answers.

CSI is fine. More about why to manage it here, Pool School - Calcium Scaling

Here is where you want CYA to be, Pool School - Recommended Levels

Then your FC target will be based on this chart, [FC/CYA][/FC/CYA]

 

[Holydoc]

Captain,

Looking at your screen capture, the CSI area shows two values. The first value (0.35) is the CSI level given the values in the first column using your current pool values. The second value (0.02) is the CSI level in the second column given that all your pool values were your TARGET values.

The suggested FC Levels area first presents you the absolute minimum values you should let your FC get if you have a salt water pool (2) or a plain chlorine pool (4). The Daily Target values are the FC levels you should shoot to maintain your pool at. So for example, when you test your pool if your FC is below 6, you should add chlorine to get to your maintenance level of 6-8. If for some reason your pool drops below an FC of 4, you are in immediate risk of growing algae and bacteria in your pool. Raise it to your maintenance level and watch carefully over the next few days for any sign of algae bloom. If you detect any signs, you will need to then start a SLAM which means raising your FC level to 20 until there is no more evidence of algae.

Probably more than you wanted, but I was bored.

 

[Captain 776]

Noooo not too much, I think it was a great answer. Thank you

Captain