Need help with Alcalinity and PH

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
Hilcun
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Need help with Alcalinity and PH

Postby Hilcun » Sat 12 Sep, 2009 10:48

Hi everyone.
I've been reading the foruns, but still I made a post.

I have a 50.000 Liters pool.
Been trying to put the water cristal clear.
I've reached the PH around 7.4 (have 3 PH testes; 2 with bromo drops, and one with paper stripes)
The PH recomended is between 7.2-7.6.

The problem is, I have the PH good, but the water is still not good:
- It's a bit clear, but It's not like cristal clear.
- The Cloro (chlorine) is always disapering.


I read the foruns and saw that the alcalinity is important.
So I measured my alcalinity and is more higher than 200.
What should I do?
Can anyone explain me what is Aeration of the water?
What kind of acid should I buy?
Should I first correct the Alcalinity, then the PH, then the Chlorine?
Should I buy anti-algie products?

Please help. Been trying to help my father for long time and never got excelent results.. only fair results :(

P.S.: I have 3 dogs that have acess to the pool, and so their hair gets into the pool every day. I have even 1 one them drinking water from the pool. Should I deny acess of the dogs to the pool? Is it n problem? Cause I get loads and loads of hair in the skimmer and filter.


Cloral
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Need help with Alcalinity and PH

Postby Cloral » Sat 12 Sep, 2009 13:06

Hi. I'm new here too, so I can't say with 100% certainty that this is accurate. Perhaps someone can come along and correct me if I make any mistakes.

I don't believe that total alkalinity affects the chlorine directly. Alkalinity tends to cause pH to rise, and high pH reduces the effectiveness of chlorine. But your pH is fine so that isn't the source of your problems. My questions would be:

1) Are you testing for free chlorine or combined chlorine? Free chlorine is what actually goes towards sanitizing your pool, but the cheaper test kits can't differentiate between the two.
2) What are you cyanuric acid levels? Cyanuric acid is the chemical that keeps chlorine from breaking down quickly in sunlight. Too little basically means your chlorine won't work. Too much is bad too, but I'm not exactly sure what problems that manifests.
3) Have you tried a chlorine shock treatment?

As for the alkalinity, you basically need to bring your pH down to 7.0 and then aerate until the pH rises. Repeating these two steps will bring the TA down over time, assuming that the new water you add doesn't have a high TA (like is the case where I live). Aerating basically means mixing air into the pool water. My pool has an elevated spa with a waterfall transfer, and this is sufficient to aerate. Other options include using an air compressor to blow air under the surface of the pool or directing your return jets to spray upwards and break the surface of your pool.
Me...
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Need help with Alcalinity and PH

Postby Me... » Fri 18 Sep, 2009 07:06

I've reached the PH around 7.4 (have 3 PH testes; 2 with bromo drops, and one with paper stripes)
The PH recomended is between 7.2-7.6.


Where does the pH tend to drift to normally? Test your fill water and post it.

The problem is, I have the PH good, but the water is still not good:
- It's a bit clear, but It's not like cristal clear.
- The Cloro (chlorine) is always disapering.


This could easily have a lot to do with the dogs. It could be placing quite an extra demand on the chlorine.

I read the foruns and saw that the alcalinity is important.
So I measured my alcalinity and is more higher than 200.
What should I do?


Alkalinity should be around 80-120ppm. This range will help to prevent the pH from bouncing around too much for one. Post the fill water results and maybe we can get an idea of where the Alkalinity comes from.

Can anyone explain me what is Aeration of the water?

Tends to raise the pH without adding chemicals

What kind of acid should I buy?

Muriatic in the wet form, my preference. There will be powdered forms also.

Should I first correct the Alcalinity, then the PH, then the Chlorine?

For now you need to maintain a free chlorine residual. Depending on the acid form you buy you will need to add it over the next several days to get the alkalinity down. If the pH starts dropping too much you can add Soda Ash or if possible aerate the water somehow.

Should I buy anti-algie products?

Only if normal free chlorine levels can't keep the algae out of the pool. Also if the pool is exposed to sunlight you need to get some cyanuric acid (stabilizer) in the water. Something around 30-50 ppm is recommended. You also don't mention calcium hardness. This should be maintained around 200-400ppm.
Hilcun
Pool Newbie
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Posts: 2
Joined: Sat 12 Sep, 2009 08:12
My Pool: My pool has near 50,000L
Location: Lisbon

Need help with Alcalinity and PH

Postby Hilcun » Fri 18 Sep, 2009 17:23

Where does the pH tend to drift to normally? Test your fill water and post it.


The pH tends to go to higher rates (8+++).

The problem is, I have the PH good, but the water is still not good:
- It's a bit clear, but It's not like cristal clear.
- The Cloro (chlorine) is always disapering.


This could easily have a lot to do with the dogs. It could be placing quite an extra demand on the chlorine.


I put chlorine but it desapears after 2-3 days... all of it. I have a test kit (I put 4 drops for chlorine and pH. Chlorine keeps disapearing!!!)

I read the foruns and saw that the alcalinity is important.
So I measured my alcalinity and is more higher than 200.
What should I do?


Alkalinity should be around 80-120ppm. This range will help to prevent the pH from bouncing around too much for one. Post the fill water results and maybe we can get an idea of where the Alkalinity comes from.


Don't know what you mean by "fill water results". I have a 50.ooo liters pool, pH always rising, Alkalinity around 200, and Chlorine keeps disapearing.
chem geek
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Need help with Alcalinity and PH

Postby chem geek » Sat 19 Sep, 2009 01:47

Your pH keeps rising because your Total Alkalinity (TA) level is too high. You can lower it via a combination of acid and aeration at low pH as described in this post.

As for your chlorine going away, I presume more quickly than normal, there are several possibilities and two of them relate to the Cyanuric Acid (CYA) aka stabilizer or conditioner level. So get yourself a good test kit -- either the Taylor K-2006 kit you can get at a good online price here or the TF100 from tftestkits.net here with the latter kit having 36% more volume of reagents so is less expensive per test.

If you have no CYA in the water, then half of the FC will break down from the UV in sunlight about every half-hour (for direct noontime sun). If this is the case, you should find that the chlorine holds overnight, but goes away during the day when the sun is on the pool. On the other hand, if your CYA level is too high (technically, the FC/CYA ratio too low), then you could have nascent algae growth using up the chlorine. In this case, you should find that chlorine also gets used up (> 1 ppm FC drop) at night as well as during the day.
Cloral
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Posts: 5
Joined: Wed 09 Sep, 2009 22:04
My Pool: 15000 gal, plaster lining, DE filter
Location: Ventura

Need help with Alcalinity and PH

Postby Cloral » Thu 24 Sep, 2009 14:39

In what fashion are you adding the chlorine? Tablets, granular, bleach, or other?
Guest

Need help with Alcalinity and PH

Postby Guest » Sun 27 Sep, 2009 17:35

ALL BLUE HERE
HI, YOU DID NOT GIVE ALL THE READINGS OF YOUR WATER. THIS IS VERY IMPORTANT TO BE ABLE TO GIVE COMPLETE INFORMATION.
BASED UPON THE INFORMATION IT SOUNDS LIKE A NEW POOL OWNER YOU ARE??
I READ DOGS IN THE POOL IT IS MY UNDERSTANDING THAT WHEN DOGS ACESS THE POOL THEY WILL URINATE INTO THE WATER YUCK! I KNOW BUT..... THAT IS AMONIA AT IT WORST AMMONIA KILLS CHLORINE. HERE IS WHERE I KEEP MY POOL S AT
FREE CHLORINE 5.O
ALKALINITY=240
PH 7.5 -7.6
CYNERIC ACID= 150
SALT=2000PPM SALT PROTECTS THE SWIMMER WITH MY HIGH CHLORINE COUNT IAM ABLE TO ONLY GO ONCE A MONT IN THE SUMMER AND EVERY TWO MONTHS I THE WINTER.
YOUR MAIN CONCERN HERE IS, SO IT SEEMS IS "NOCHLORINE" SUPER CHLORINATE WITH TRICHLOR POWDER OR CRUSH UP 6 TABLETS IN THE SKIMMER, THIS WILL RAISE THE CHLORINE LEVEL, LOWER THE PH, AND ADD CYNERIC ACID ALL AT THE SAME TIME, IF YOUR CONCERNED ABOUT HURTING THE DOG ADD SALT TO THE WATER A LITTLE SALT IS BETTER THAN NO SALT APROX 8 -40 LB BAGS WILL GIVE YOU ABOUT 1,600 PPM OF SALT IN A 25,00 GAL POOL. I HAVE FOUND IF WE HAVE THE ADDITIONAL CHEMS IN THE POOL WHEN SWIMMERS, DOGS STORMS, OCCUR THE WATER HAS RESERVES TO COMBAT THE OUTDOOR SITUATIONS. ALL BLUE POOLS ALAN
chem geek
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Need help with Alcalinity and PH

Postby chem geek » Sun 27 Sep, 2009 23:08

Alan,

Please do not use all caps. It is hard to read.

Your 5 ppm FC with 150 ppm CYA is not sufficient to prevent algae growth in all pools without using a supplemental algaecide or regular shocking. In another post you mentioned that you used a copper-based algaecide in pools that had algae problems in spite of the levels you maintain. If you are only adding chlorine once a week to your pools, then the chlorine level will be swinging and not at 5 ppm FC at all times. If instead you are using a Trichlor inline chlorinator, then the CYA level will rise. For every 10 ppm FC added by Trichlor, it also increases CYA by 6 ppm. Even with a low 1 ppm FC per day chlorine usage, Trichlor will increase CYA by over 100 ppm in 6 months if there is no water dilution. How are you keeping the CYA level from rising in your pools?

The high Total Alkalinity (TA) level will tend to make the pH rise if you are using a hypochlorite source of chlorine. So this implies that you are using Trichlor as your source of chlorine since that is acidic. You didn't list the Calcium Hardness (CH) level which I assume is lower to compensate for the higher TA level, is that correct?

Richard

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