Order of adding Chemicals

TTWB

Member
Jul 14, 2019
9
Annapolis, MD
I have a question on the ORDER or sequence of balancing chemicals in opening.
I did not see answered in pool school or the guide to opening pools or in the SLAM instructions, but I may have read these all too quickly.

SLAMing identifies get the pH correct first. What if CYA is below 20?.
It would seem that adding acid would impact the pH?
It seems that on opening the concern is getting FC to the correct level. and for that to work the pH needs to be correct and for that to be "stable" the CYA should be at a "good" starting point.
Is the order then:
Get CYA up to 25-30 with "stabilizer (Cyanuric Acid: 100%)[Pool math 3lbs 11 oz]
Check pH...let assume that the pH is 8+
Lower pH to target 7.2-7.4 by adding dry acid
Adjusting pH is dependent on Total alkalinity! TA is 70, below the 80-110 level!
Do I need to get the TA up first??? Start with a good TA?
(what is the difference between "TA" and "adjusted TA" [Alex water testing])
With CYA 20 and FC=0 (below the level on the chart) 2 lbs 9 oz of Calcium Hypochlorite 73%

As SLAMing procedure identifies the chlorine level checking will be iterative and checking any other chemical level will be in error.
My experience in SLAMing or achieving 'break-point" chlorine has been much more than 3 lbs of Cal-Hpo. it has been on the order of 12-14 gals of liquid CL (not available currently). BioGuard water analysis recommends 3 gals, but I don't know the concentration (I have 12.5%)
(SLAMing and achieving "break-point chlorine" are not exactly the same but have similar intent)

I suspect there is difference in order based on the objectives of getting levels up as in SLAMing and maintaining levels. I think in maintenance getting the TA level correct then adjusting pH
Through out the season I can work on hardness, TDS, et al

Thanx for any insight on the order in adjusting pool chemistry on opening
(I am amazed at the variances in the resultant recommendations in all of the "pool calculators" out there given the same measurements)
 
Welcome to the forum!
A couple statements. CYA has very little effect on pH unless you add a lot of it at once.
The TA can be anything above 50 ppm as long as pH is steady and your CSI is in range for your system. Not sure were you got the 80-110 ppm for TA.
Breakpoint chlorine is term not used in TFPC. It is technically not correct. So ignore that.
Do not 'adjust' your TA. Use PoolMath. Be sure to use a proper test kit. Quit using the BioGuard stuff. Expensive and contains things you do not need.

A new fill. Get 3 ppm FC in the water. Get 30 ppm CYA dissolving using sock method. Adjust pH to the 7's. Keep FC in target range for CYA.

SLAM. Adjust pH to 7.2. Start dissolving CYA if needed to get to 30 ppm. Raise your FC to SLAM level based on your CYA.

I suggest you read ABC's of Pool Water Chemistry.
 
One more thing. Stop using Dry Acid. It adds sulfates to your water. They build up. Then they destroy metals.
Use muriatic acid to adjust pH.
 
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Thank you very much for the response!
You kindly answered my question wrt order.

Only this year am I using Bioguard brand, becasue it was a gift and it is fresh.
I suspect the non Biogaurd sanitizers (CL) is not fresh and maybe my current problem.

Acid having very little impact on pH seems counter to my thinking, unless I add a lot. All sources(pool Math, Alex, Pool Chemistry calculator 1+ 2 ) recommend adding 6lbs. 6lbs may not be a lot, but added per label instructions. I do not know what " a lot" is. Adjusting from zero to 30+ seems like "a lot"?

Agree TA can be "anything above 50" and is holding at 90-100. Added nothing to to adjust TA; it is within levels

You asked whre I got the TA levels
TA 80-120 (110 is from the pool installer and BioGuard label is 125-150) from;
"Pool wizzard" Total Alkalinity (TA) in swimming pools - POOL WIZARD
Orenda Technologies Total Alkalinity vs. pH, and Their Roles in Water Chemistry
"Poolonomics" Pool Alkalinity: Everything You Need to Know About Total Alkalinity & Pool Water
"Swimmingpool.com" Pool Total Alkalinity & Pool Water pH Level | SwimmingPool.com
And
National Swimming Pool Foundation: Water Chemistry Guidelines

I have read and enjoyed both The ABCs and "what are my pool levels" - very good.

I agree that "Breakpoint chlorine is term not used in TFPC "
Whether it is is "correct" is probably debatable.
Some Sources:
And
https://www.in.gov/isdh/files/BPM%20Shock%20the%20Pool%202019.pdf PDF (363k)
https://www.in.gov/isdh/files/BPM Shock the Pool 2019.pdf
Chemical_adjustment_pool.pdf. Addendum. 7. Breakpoint Chlorination Graphical Representation of Breakpoint Chlorination. ... Breakpoint chlorination. Achieving Breakpoint Chlorination. Calculating Amount of Chemical to Achieve Breakpoint Chlorination.

Essentially these source provide an insight to why TFP process of SLAMing works. I am following the TFP SLAMing process

I sincerely appreciate the order you provided.
I started the process today. (Fresh Taylor Test kit 2006 or something)
Using Pool math I added CYA to acheive 30
I did not need to adjust TA as it is sitting at 96
I lowered the pH from 8 to 7.2 using Sodium Bisulfate: 93.2%, and Pool Math amounts
I am using dry acid as it was a gift and I do not have access to alternatives currently

With that as a start. I am currently trying to get Free Cl to 3 PPM as you suggest:
"A new fill. Get 3 ppm FC in the water. Get 30 ppm CYA dissolving using sock method. Adjust pH to the 7's. Keep FC in target range for CYA. "
I can't do anew fill of 22K gals, especially if most all chemistry indications, except CL, are good.
I added 3 gals 12.5%; every thing running, waited two hours, measured zero CL on strip stick and FAC DPD method 0.8 FC and in excess of 2.8 PPM CC (more than 14 drops! Never went from Pink-red to clear). I did not believe this number so I tested it again with same results. Test strip "Insta Test by LaMotte has correlated well with Taylor in the past.

Either the 3 gallons of 12.5% CL was old and not effective or there is something else wrong.
I have added from a different source another 3 gals of liquid CL.
I'll wait 2 hours and test again and compare the Free CL and CYA relationship. (In my case I think it is 5PPM)

Thank you again for the constructive and helpful response.
R,
Todd
 
Thank you.
I may start a new thread; I I am having a very difficult time in getting the chlorine levels up.
I did switch from liquid to Cal-Hypo as after reading the date codes these gallons are 1 year old :-(
Thank you for your insight, a I have got all levels withing good zones, except Free Cl!
R,
todd
 
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