Adjusting the Chemistry. Order of Operations?

[jjherm7]

Still a total noob, but learning! Just finished my first SLAM a couple days ago and passed the OCLT. Have been letting my FC drift back down, and just ran my full battery of tests. Here's what I got.

FC - 3
CC - .5
PH - 6.9
CH - 175
TA - 50
CYA - 20

We had a huge rain yesterday which probably brought my CYA down. I have a vinyl pool, so should I just ignore CH?

I guess my question is, is there a specific order I should be adjusting all these levels? Adjusting one thing first and getting it in line before moving on to something else?

 

[Mike1162]

PH is a good place to start. 3 is probably the minimum you want for FC.
Have you decided on a CYA level yet? I'd check that again before making an adjustment.

 

[jjherm7]

I'm thinking 30-40 seems good for me for CYA. We're supposed to have heavy rain the next few days, so should I even bother adjusting this yet since it will most likely get diluted down anyway?

But you're generally thinking I should go CYA, then PH, then FC?

 

[Mike1162]

Adjusting before or after the rain won't make much difference unless you end up having to pump some water out of the pool. Even if you have to pump out 2 inches that'll only 'waste' about 5% of the chemicals. I'm also new to this but believe everything in your pool is close enough that the order won't matter. If you're new to the CYA test then repeat before making any changes. I'd shoot for 30 & retest at the end of the week.

 

[pooldv]

You need CYA in there to protect the chlorine from the sun and buffer the harshness. It can be added at any time, in a sock in the skimmer, test a week later after it is fully dissolved.

It is important to maintain PH between 7.2 and 7.8 at all times. It can be adjusted anytime except when FC is above 10 because the PH test is not valid when FC is above 10. Use Borax to raise it and muriatic acid to lower it.

It is MOST important to maintain chlorine at target level for your CYA at all times so that your pool is properly sanitized and algae free, Chlorine CYA Chart. Letting FC drop below minimum level will leave the pool unsanitized and algae will start growing.

It is safe to swim when:
PH is 7.2-7.8
Chlorine is between minimum and shock level
Water is clear

CH is not very important in a vinyl pool, under 350 is fine.

TA is low. TA is relational to PH so when using poolmath make sure both numbers are in there. Use baking soda to raise TA.

Here are some Pool School articles that cover all this in more detail.
Pool School - ABCs of Pool Water Chemistry
Pool School - Recommended Levels
Pool School - Recommended Pool Chemicals
Pool School - PoolMath

 

[Pogueld]

You ALWAYS want to keep your FC in check. That's a daily check and maybe even twice a day until you figure out what your pool needs. You don't ever want the FC to fall below the minimum for your CYA level.


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