Green pool. High PH, Low alkalinity. Please help!

tangte

Member
Feb 16, 2017
13
Tallahassee
My pool was flooded around about 1 week ago by a big storm. A lot of water rushed in from my lawn. It turned dirty, really dirty....After a few days of circulation, the pool turned green and cloudy. Two days ago, I decided to give it a super shock. I added 1 gallon liquid chlorine and and 5 bags of HTH super shock (1lb per bag). It has been circulating for more than 24 hours, no change at all. Normally, when my pool turned green, 2 bags of the HTH super shock can turn it back. But this time, I put in 5 bags plus a jug of liquid chlorine, and no change. So I took my water sample to the pool store. The report is attached. The chlorine level is really high, as expected. PH is 8 (high), and alkalinity is 70 (low). It is also saying "Mustard algae: Extensive". (not sure how they figured this out, how does the pool store test for mustard algae?)
The pool store suggested me to add 10 pound of baking soda first, to fix the low alkalinity problem. Then use the YellowGone product. But I am a bit confused here. For some reason, it seems that the chlorine is not working effectively. I suspect it is because of the high PH value. The pool store said the high PH is because of I put too much chlorine in there. If I add 10 pound of baking soda in there, wouldn't that make the PH even higher? Should I add muriatic acid in the pool instead? I am totally confused here. Any suggestion is appreciated.
 

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dfwnoob

Gold Supporter
Feb 27, 2022
208
DFW
Pool Size
15000
Surface
Plaster
Chlorine
Liquid Chlorine
Other, much more talented people in pool chemistry will pipe in here - but I would suggest not adding anything to the pool right now beyond fresh liquid chlorine and muriatic acid to bring the pH back down in preparation for a SLAM.

Not that Pool Store tests should really be taken as gospel (and to help you actually fix this, you need to invest in a good test kit), but with no CYA, your chlorine is getting the one-two punch from both working on the algae and being destroyed by sunlight. I'll let others chime in as to whether or not to add CYA now as that's getting beyond my low level of expertise. :)
 

YippeeSkippy

Mod Squad
Gold Supporter
LifeTime Supporter
Jan 17, 2012
18,987
Evans, Georgia
STOP!! Do NOT add anything the pool store told you to add. They're clueless.
GREEN = ALGAE. :alien:

TA of 70 is perfectly acceptable.✅

Each bag of "shock" is as much calcium as anything else. Sometimes too much calcium can be a problem.

The pH of 8 is on the high side but nothing alarming. A bit of Muriatic Acid will take that down. The pH is NOT high due to chlorine.

The liquid Chlorine is the only thing I would recommend, but in higher doses and with lots of brushing and filtration.

I do NOT trust any of those test results as they really make little sense. We work on test results users do themselves using a test kit that contains the FAS-DPD test.... either Taylor K-2006C Amazon or TF-100 from www.tftestkits.net

What else have you put in your pool? How do you normally sanitize the water?

I would suggest you obtain and use your own trusted test kit (no one cares more about your pool than you do) and read a bit of our teaching articles and we'll help you clean that mess up.

We need you to also make out a <Signature Line> found under <Settings> describe your pool, its type, equipment in use, how you sanitize and test. This helps us enormously.

ABCs of Pool Water Chemistry
Recommended Levels
SLAM Process



Maddie 🇺🇦
 
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tangte

Member
Feb 16, 2017
13
Tallahassee
STOP!! Do NOT add anything the pool store told you to add. They're clueless.
GREEN = ALGAE. :alien:

TA of 70 is perfectly acceptable.✅

Each bag of "shock" is as much calcium as anything else. Sometimes too much calcium can be a problem.

The pH of 8 is on the high side but nothing alarming. A bit of Muriatic Acid will take that down. The pH is NOT high due to chlorine.

The liquid Chlorine is the only thing I would recommend, but in higher doses and with lots of brushing and filtration.

I do NOT trust any of those test results as they really make little sense. We work on test results users do themselves using a test kit that contains the FAS-DPD test.... either Taylor K-2006C Amazon or TF-100 from www.tftestkits.net

What else have you put in your pool? How do you normally sanitize the water?

I would suggest you obtain and use your own trusted test kit (no one cares more about your pool than you do) and read a bit of our teaching articles and we'll help you clean that mess up.

We need you to also make out a <Signature Line> found under <Settings> describe your pool, its type, equipment in use, how you sanitize and test. This helps us enormously.

ABCs of Pool Water Chemistry
Recommended Levels
SLAM Process



Maddie 🇺🇦
Thank you for you suggestions. I just added a brief signature line, will fill in more details later. My pool had a salt generator, but the cell has been broken. So I have used liquid chlorine in the past year. Occasionally I used that HTH shock stuff. I put no other chemicals in my pool. I do have a cheaper 5-way test kit. I actually did some test before I went to the pool store. My self test results also showed high free chlorine level and high PH (about 8). So, I guess I should dump another 2 jugs of liquid chlorine in there and keep the pump running? Should I put in some muriatic acid first, to bring the PH down to 7.4? Thanks!
 

YippeeSkippy

Mod Squad
Gold Supporter
LifeTime Supporter
Jan 17, 2012
18,987
Evans, Georgia
Run a full set of tests-
FC
CC
pH
TA
CH
CYA
Salt

have you seen the nifty PoolMath which can help you by telling you how much acid to use to lower pH to whatever you decide. I'd take it to 7.2 in steps if necessary because you're going to need to do a SLAM procedure to clear up that pool.

You need the FAS-DPD tester for high level chlorine/CC testing.--> FAS/DPD Chlorine & CC's test

Until we get a full panel of test results Id suggest adding a gallon of Liquid Chlorine per day and brushing the pool daily.Until we know what your CYA is I would avoid swimming.

Can you do this?
 

PoolStored

Gold Supporter
TFP Guide
Jun 24, 2021
1,690
Ashtabula, OH
Pool Size
30000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-60
Let's greatly simplify this for you.
1) TA is not your issue. Ignore it for now.
2) Go buy the TF-100 Pro test with smart stir. You will not regret it, do it now. TF-Pro with SmartStir
3) Go to the Tallahassee Lowe's and get this: https://www.lowes.com/pd/Pool-Essentials-1-Gallon-Liquid-Pool-Chlorine/5001527059. It is in stock, Isle 1, Bay 2. Buy about 10 gallons. Will get you through until your get test kit. You may need more later.
4) Add a gallon of LC per day until your test kit arrives. Pour it slowly, like 1 gallon over 2 minutes over the return to the pool. When you are done, brush, brush, brush the area under the return.
5) Download PoolMath. Figure out what concentration of Muriatic you have, and use Pool Math to figure out how much MA to add to reduce your pH to about 7.4. Again, add SLOWLY (Acid to Water), and brush, brush, brush. Getting pH down is not super critical, but since you need to wait for your test kit, is OK to do.
6) When your test kit arrives, do your testing, instructions included, and post results back here.
7) It is likely you will need to SLAM. Do a bit of reading to prepare: SLAM Process

If you need confirmation that we know what we are doing, check this out! What does TFP clear look like?
 
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tangte

Member
Feb 16, 2017
13
Tallahassee
Let's greatly simplify this for you.
1) TA is not your issue. Ignore it for now.
2) Go buy the TF-100 Pro test with smart stir. You will not regret it, do it now. TF-Pro with SmartStir
3) Go to the Evans, GA Lowe's and get this: https://www.lowes.com/pd/Pool-Essentials-1-Gallon-Liquid-Pool-Chlorine/5001527059. It is in stock, Isle 1, Bay 2. Buy about 10 gallons. Will get you through until your get test kit. You may need more later.
4) Add a gallon of LC per day until your test kit arrives. Pour it slowly, like 1 gallon over 2 minutes over the return to the pool. When you are done, brush, brush, brush the area under the return.
5) Download PoolMath. Figure out what concentration of Muriatic you have, and use Pool Math to figure out how much MA to add to reduce your pH to about 7.4. Again, add SLOWLY (Acid to Water), and brush, brush, brush. Getting pH down is not super critical, but since you need to wait for your test kit, is OK to do.
6) When your test kit arrives, do your testing, instructions included, and post results back here.
7) It is likely you will need to SLAM. Do a bit of reading to prepare: SLAM Process

If you need confirmation that we know what we are doing, check this out! What does TFP clear look like?
Thanks for the help, from all of you. The TF-100 test kit is on the way. I will perform a full test once I get it.
 
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