Please look at these water chemistry numbers > comment

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Turbota

Turbota

0
Jan 14, 2013
42
SW Florida
I am trying to establish a minimum and maximium PPM for the various pool water chemical tests, but everywhere on the internet I have read, I get different numbers, so I kinda took an average of what I have found and came up with the numbers listed below.

Will you look at these and tell me if they look like ideal PPM numbers for an in-ground cement / gunite pool (non-salt water).

BTW ... I looked at one video where the guy said to always test the (TA) 1st, and correct it before proceeding with other tests. (pH) is to be adjusted 2nd, and then the (FC) is 3rd to be tested and adjusted before proceding with the rest of the tests.

Anyway, here is the numbers I have come up with ... how do they look to you?

Thank's
________________________________

(TA) Total Alkalinity:
80 - 110 PPM
If Low - Add: Calcium Carbonate (Always test and adjust 1st)

pH
7.2 - 7.6
If Low - Add: Muratic Acid (Always test and adjust 2nd)

(FC) Free Chlorine:
1 - 3 PPM
If Low - Add: Chlorine (Always test and adjust 3rd)

(CC) Combined Chlorine:
0 - .5 PPM
If High - Add: Shock Treatment

(CH) Calcium Hardness:
180 - 300 PPM
If Low - Add: Calcium Chloride

(CYA) Stabilizer:
30 - 70 PPM
If Low - Add: Cyanuric Acid

Borate:
30 - 50 PPM
If Low - Add: Borax
 
You should take a look at our Pool School article on Recommended Levels. It differs in several minor, but important, ways from what you posted. There is a fair bit of information about the whys of the levels we recommend in Pool School, but really getting into it is in a couple of topics in The Deep End.

Also, there is absolutely no point in testing TA first. FC should be first, and PH second, and both fairly quickly after taking the water sample. After that it doesn't much matter what order you do the tests in or how long you wait (within reason).

For order of adjusting, TA should be first only if it is way out of range low. There is a similar rule about PH, you only really need to adjust it next if it is noticeably out of range. FC is the number you usually start with, since TA and PH are usually plausible, and maintaining FC levels is really the most important of all of the numbers. Everything else can usually be put off a few days if needed and done in whatever order.
 
Re: Please look at these water chemistry numbers > comment

Why keep searching the internet when you already found us ;)

There are some flaws in your summary. Most notably the FC levels which are highly dependant on your CYA level. This is the major relationship that seems to not be well understood by most people.

As Jason said, read through Pool School to see what we recommend and why.

Posted from my Droid with Tapatalk ... sorry if my response is short ;)
 
1 I would not advise testing and adjusting your TA first, it is a weekly/fortnightly check and does not change drastically enough to justify regular testing and correction, even when I am testing the water quality I always go through the following process pH FC TC then weekly TA CH then monthly CYA once I have a full set of results this will dictate what chemicals if any are required to be added, which usually results in Calcium Hypochlorite / Bleach first (Chlorine) then TA correction (very infrequently needs correction), then pH, CH, CYA

2 pH and Chlorine should be your regular checks, with Chlorine being added regularly, and depending on your source water and/or chlorine source regular acid or alkali additions to keep to keep pH in check at a level that your pool is happy with

3 Calcium Carbonate is a pH increaser, and does not increase TA, Muriatic Acid is an acid and will therefore LOWER pH (not increase)

3 Each chemical you add has a pH effect on water, be it a little effect or a big effect, for example adding Sodium Bi-Cardbonate will also increase pH

4 CYA and Chlorine have a relationship which each other that changes the recommended levels dependant on your CYA level, you should familurise yourself with the pool school article on Chlorine/CYA.

All of the levels you list as recommended are dependant on a number of factors, the recommended levels for your pool are listed in Pool School, along with Recommended chemicals and a basic pool care schedule.

pool-school/
 
Turbota, you listed "calcium carbonate" to add if the TA is low. If calcium carbonate powder actually dissolved when added to water, yes, it would raise the TA, also the CH, and also the pH. But calcium carbonate is not soluble. Adding that chemical would just cloud up the water. The chemical to add for raising the TA is sodium bicarbonate.
 
Agree FC should be tested first, then PH. I believe these two components are the most critical. CYA level will drive the minimum FC level to maintain.
In simplistic terms, TA is a buffer to maintain PH swings, and CH is there to tweak the CSI in plaster pools.

Couple of links you may find worth wild to read:
pool-school/pool_water_chemistry
http://www.poolcalculator.com/chemistry.html#FC

Also the numbers provided are guidelines, each pool will be different, you don't want to fight the natural balance of your pool. With that being said, read about the CYA/FC relationship. Really once you understand that, I feel 3/4 of your maintenance regiment will be complete. In 20 months of finding this site I've never had green/funky water and only had to do the shock process twice (high bather loads/dogs in pool).

If your PH naturally runs at 7.8 that's ok, and you have low CH (120) in your fill water, that works out in your favor. It's best to run a slightly negative CSI, you'll have less chance of scale. Pool caculator (http://www.poolcalculator.com) can help figure your numbers.

Hope the info helps and welcome to the forum.
Bob
 
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