High TA/low pH problems - can't increase pH

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
Eddles
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High TA/low pH problems - can't increase pH

Postby Eddles » Thu 13 Jun, 2019 17:14

Hi all, I've already read the sticky titled "Reduce Total Alkalinity Levels" but I am having problems increasing the pH, so please bear with me...

Problem:
My parents have a swimming pool and hot tub over 15 years old. My dad recently developed dementia and was doing chemicals wrong, so I've taken over responsibility for the pool but I'm a bit out of my depth and my dad is no help really, he's quite confused.

We've had issues with cloudy water in both the pool and hot tub. I've fixed the pool, somehow. It's crystal clear, but I can see a faint white haze in front of the pool lights, don't know if that's normal? Regardless, I'm a bit concerned about our TA levels. The pool has a Fluvo counter-current exerciser with built-in aerator. I ran the Fluvo for about 3 hours with the nozzle pointing upwards with the air mix set to maximum but the pH level didn't change one bit, I checked immediately before and after the Fluvo run and then the morning after - the pH was 7.3 throughout. Would the Fluvo help with the pH change, or would I need to make a plastic pipe aerator with an air compressor?

Today, the measurements taken before adding chemicals are:

FC: 0.0 (yes I'm aware it's not meant to be zero, I've already added in chemicals)
TC: 0.4
pH: 7.2
TA: 290
CH: 380
CYA: <30

My pool: Tiled, indoor & in-ground 66,000 litre pool
Pool chemicals: Chlorine granules, Sodium Carbonate pH increaser, Sodium Bisulphate pH reducer, Oxyshock, and others.
My pump & filter: Bomba PSH ND-14M, AstralPool Cantabric sand filter and UV filter system.
Other info: ?

I'll really appreciate any advice!


Teapot
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Re: High TA/low pH problems - can't increase pH

Postby Teapot » Fri 14 Jun, 2019 00:49

It's the fine fogging air bubbles that work the best but needless to say with that level of Alk you should be getting an increase. The best way to see stuff in the water is in front of a pool light as you have. It could be the filtration simply isn't good enough to remove it. Could try a clarifyer like jollygel,
If your pH is that stable why not stop worrying? My water supply is around the same and I didn't worry over it for around 5 years of pool's life. Similar water hardness as well.
Eddles
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Re: High TA/low pH problems - can't increase pH

Postby Eddles » Fri 14 Jun, 2019 07:35

So I should continue to use the fluvo for longer than 3 hours? The pH is fairly stable, but it slowly drops over time, so I have to add in sodium carbonate to increase the pH which will increase the TA in turn. Many thanks for responding!
Denniswiseman
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Re: High TA/low pH problems - can't increase pH

Postby Denniswiseman » Fri 14 Jun, 2019 10:56

Your chlorine granules are Dichlor which will raise your CYA and also as it's an acid will work against your pH
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm

So for every increase of FC by 10ppm you also raise your CYA by 9ppm which doesn't decrease with the chlorine usage but stays in the water

Use these common products to sanitise and balance your water
Liquid chlorine (sodium hypochlorite or plain bleach)
Muriatic acid (hydrochloric acid) to lower pH and TA
Bicarbonate of soda to raise TA
Aeration will raise pH only
Soda ash will raise pH and TA


Leave the Fluvo on overnight and try and get as much aeration as possible. Three hours isn't long enough
I use a large pond aerator which really puts the air in at 100 litres/minute
Teapot
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My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: High TA/low pH problems - can't increase pH

Postby Teapot » Fri 14 Jun, 2019 11:58

It's a bit strange Dennis because with a TA of 290 the pH buffer is so strong the pH should not fall at all and should be holding at around pH8.1-8.3.
If the CYA level is higher than stated then that acts as a pH buffer downwards so then the pH could fall.
Something isn't quite right.
Eddles
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Re: High TA/low pH problems - can't increase pH

Postby Eddles » Fri 14 Jun, 2019 15:04

Hmm, yes there is something strange going on. I've double-checked all the chemical measurements using a dip-strip, all the numbers match. The pool's pH has always falling down steadily ever since I took over the pool at the start of April. The hot tub is opposite, it always shoots up. What else should I check? The sand has been replaced a few weeks ago, and I've done a backwash a handful of days ago.

Saying this, I have to say that I'd like to clean the pump's strainer basket but when I undo the bolts holding the plastic cover down, water would leak out, so I just close it down again. How do I access the strainer basket in the pump without draining too much water?

Many thanks!
Denniswiseman
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Re: High TA/low pH problems - can't increase pH

Postby Denniswiseman » Fri 14 Jun, 2019 17:14

Forget about the sand and backwash untill the pressure increases
How are you testing, with a FAS/DPDtest kit?
Where in relation to the pool is the equipment. I would have thought if it had been lower there would have been valves
Images would help
Keep aerating and using muriatic acid to lower TA & pH and then aerating
Eddles
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Re: High TA/low pH problems - can't increase pH

Postby Eddles » Fri 04 Oct, 2019 08:45

Hi all,

Interesting update - I've arranged for the pool to be drained on Sunday evening, however 5 days ago, I added in chlorine and the level shot up to about 50, an it has stayed up there ever since - I've never ever had a chlorine level over 2 ever since I started looking after this pool! I've checked cyanuric acid level and it's about 120, I was really surprised. The water never looked so clear too. Does this mean I don't need to change the water? It's better to leave the water as is and bring the chlorine level down? How come did the cyanuric acid level crash down?

Many thanks for your time!

With kind regards - Piers
Denniswiseman
Pool Industry Leader
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Posts: 1326
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: High TA/low pH problems - can't increase pH

Postby Denniswiseman » Fri 04 Oct, 2019 10:06

Eddles wrote:Hi all,

Interesting update - I've arranged for the pool to be drained on Sunday evening, however 5 days ago, I added in chlorine and the level shot up to about 50, an it has stayed up there ever since - I've never ever had a chlorine level over 2 ever since I started looking after this pool! I've checked cyanuric acid level and it's about 120, I was really surprised. The water never looked so clear too. Does this mean I don't need to change the water? It's better to leave the water as is and bring the chlorine level down? How come did the cyanuric acid level crash down?

Many thanks for your time!

With kind regards - Piers

Testing error?
If you have a CYA of 120 then your slam level of free chlorine would be 48
If you have ammonia that could lower the CYA
If all your levels are in a manageable level leave your water alone, the chlorine will reduce over time
If you are closing soon check again in the spring
Eddles
Pool Enthusiast
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Posts: 28
Joined: Mon 10 Jun, 2019 16:09
My Pool: 66000 litre indoor swimming pool with UV and sand filtration, and 1200 litre hot tub.

Re: High TA/low pH problems - can't increase pH

Postby Eddles » Fri 04 Oct, 2019 12:39

Can't be testing error as I use the same test equipment/reagents for the hot tub and the levels are correct for the hot tub.

I'll cancel the drain, leave it and see how it goes - this will save us a large amount of cash.

I've not put in any ammonia - unless someone had been peeing in the pool all this time?

Many thanks!
Denniswiseman
Pool Industry Leader
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Posts: 1326
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: High TA/low pH problems - can't increase pH

Postby Denniswiseman » Fri 04 Oct, 2019 15:05

You wouldn’t have put any in, it’s a chemical reaction
Eddles
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Posts: 28
Joined: Mon 10 Jun, 2019 16:09
My Pool: 66000 litre indoor swimming pool with UV and sand filtration, and 1200 litre hot tub.

Re: High TA/low pH problems - can't increase pH

Postby Eddles » Fri 04 Oct, 2019 17:57

Ah I see, what chemical reactions would cause the ammonia?

Many thanks!
Denniswiseman
Pool Industry Leader
Pool Industry Leader
Posts: 1326
Joined: Tue 06 Sep, 2011 05:48
My Pool: 10k inground fibreglass, Telescopic Cover, Hayward Powerline pump, Quality filter with glass media, 27kw output heat pump, K-2006C test kit
Location: United Kingdom

Re: High TA/low pH problems - can't increase pH

Postby Denniswiseman » Sat 05 Oct, 2019 10:20

I found this online to help explain it
Elements excreted by swimmers, such as sweat and urine, are largely comprised of three main elements: water, urea and ammonia. As the components of urine and sweat are broken down by the pool water and the chemicals that are present in the water, ammonia is separated out and becomes recognizable in water tests. The ammonia found in urine alone is not harmful to swimmers; however, when combined with chlorine, it may cause symptoms such as eye irritation in some swimmers.
A heavy SLAM dose of chlorine will break it down

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