Extremely high CH - can this lead to chronic cloudiness

[tuxedy]

Hi all. Struggling with a pool that is constantly cloudy but has proper color (blue). Readings:
ph: 7.4
fc: 5.5
cc: <0.5
ch: 1025
TA: 50
cya: 30

Located in Rwanda, I've always used sodium hypochlorite 65 as my primary chlorination source as well as for slamming the pool. Liquid chlorine not available in large quantities here. My fill water is extremely soft at 50-100, and rarely do add since it rains a lot here.

My CH in the past was usually around 700 and I kept my TA low as well as ph usually around 7.4 Recently CH moved up to 825 or so but was managing the pool okay. Chlorine loss per day is 1.5-2 with not much overnight loss. Over the summer it barely rains here but don't add water that often. The pool's consumption of Cl was pretty consistent but never got that sparkling clear water in a while since late June. ph would creep up in the summer more than normal, (I would go weeks without adding any acid but in the summer with a lot of sun I would be adding almost weekly or biweekly to bring back ph down) I bit the bullet and decided to start slamming last week despite no OCLT but just with the pool being cloudy. Over the 6 days I was adding about 6-8 ppm per day. No OCLT but still cloudy. I checked the pool hardness and it was quite high. I decided to stop after 6 days since there was no change whatsoever to the pool in those 6 days. (in the past it would take 3-4 days to see some instant change)

Using Taylor's CSI wheel when I put in my info with water temp of 21C I get 0.3 or 0.4 but in pool math it shows balanced! I'm quite confused about that.

I decided to try adding acid to 7.2 to lower my csi more and see if that helps. the pool hardness is from using cal hypo for daily and slamming. I recognize that. I also recognize I may need to drain some of my pool but want to avoid that until next year when I hope to repaint the pool (acyrlic). Any thoughts?

 

[mgtfp]

I've always used sodium hypochlorite 65

I guess you mean calcium hypochlorite here.

Using Taylor's CSI wheel when I put in my info with water temp of 21C I get 0.3 or 0.4 but in pool math it shows balanced! I'm quite confused about that.

I would trust PoolMath in general. One unknown with pools where salt is not being tested is the salt level, that accumulates over time with used chlorine turning into salt. PoolMath assumes I think salt 1000ppm if salt not tracked. Not sure what the wheel does. There might be other differences in how CSI gets calculated. Not sure.

How stable is your pH at 7.4? As soon as that rises, CSI will be much higher. And is your water temp really only 21°C?


Not sure if that would work to check if the cloudiness is calcium related: You could take a sample in a glass and add a few drops of acid straight to it. That might bring calcium back into solution.

Do you have scaling on any surfaces?

 

[tuxedy]

Scaling doesn't seem to be bad, then again I have white pool paint ... there are areas where the paint looks a bit crusty and almost light brown. which could be some scaling, not quite sure. Near the tile line it's also white too.

Another weird thing is that when I use my DPD powder in the water, it's really cloudy when I add it. even with the drops back to no color its really cloudy. ITs a brand new bottle of powder.

 

[tuxedy]

I did change the ph to 7.1 and it helped quite a lot, but still not as clear as I'd like it to be.

 

[mgtfp]

If you have no OCL, and if you always kept your FC above minimum, than algae seems unlikely, and continuing to slam would just add more calcium.

Usually cloudiness from calcium comes together with high TA, which is not the case for you. There might be other calcium scales involved like calcium sulphate or phosphate. Have you ever used sulphur based acids to control pH? And even if we usually say that phosphates don't matter much for algae, they can become a problem together with high calcium in forming calcium phosphate scale, so it might be worth testing for phosphates.

You could also try to bump up your filtering by adding a bit of pool grade DE powder to your sand filter.

Long-term, an SWG might be the best way forward for you to avoid cal-hypo.

Maybe @JoyfulNoise or @JamesW have another suggestion?

 

[HermanTX]

I did change the ph to 7.1 and it helped quite a lot, but still not as clear as I'd like it to be.

I see you have a sand filter. Have you backwashed it recently? Filtering helps clears the water and should be a consideration.
Also, please read

CSI and LSI - Further Reading

www.troublefreepool.com

 

[JamesW]

Calcium hypochlorite always causes cloudiness.

Having a high calcium level only prolongs the cloudiness.

If you use calcium hypochlorite every day, the pool will probably never be clear.

Also, all paint chalks and that will also contribute to the cloudiness.

To solve the cloudiness, you should resurface with plaster and stop using calcium hypochlorite.

 

[tuxedy]

Thanks for all the responses. It's possible to get a SWG here, and yes that might be a better long term solution. I can get trichlor but I use that every few months to get both chlorination and stabilizer up at the same time.

 

[tuxedy]

Also plaster is not an option here in this country, no one has access to the material. It's only painted concrete or tiling. Tiling was out of our budget at the time.

 

[mgtfp]

Could a vinyl liner be an option?

 

[tuxedy]

So weird things have been happening to my pool.
pH: 7.6
Alk: 40
CYA: no longer existent
CH: 1000

I know these numbers aren't the greatest, but again, perspective living in Africa with no access to affordable liquid chlorine and only granulated cal hypo (which everyone uses in this country as their main chlorine source)

My paint surface is really starting to bubble and burst and there often fine green algae on the exposed areas of concrete. Our pool is now 2 years painted and we wish to wait another year. Thinking that I can see algae and all I'd figure my chlorine use would increase but it hasn't, in fact it has decreased dramatically. The pool used to consume 2-2.5ppm in the past. Nowadays it is consuming 1.25-1.5ppm daily. It's the weirdest thing. I don't even have any residual CYA in the pool anymore. I used to have 30,40 CYA and I didn't notice much of a drop. So my chlorine consumption is lower than it has been ever in the past, and I am only running the pump 3 hours a day instead of 5. Honestly, I took this approach since I can't do much slamming anymore at the risk of adding more and more calcium into the pool!

The pool is constantly slightly cloudy, not crystal clear and I figure that is from some algae on the walls and the hardness being so high. Since I am waiting to repaint the pool next year I've just been allowing the pool to look like this. My hypothesis is that since the pool has high hardness and some of it is precipitating out, is there a chance that the water being a bit turbid is letting less UV into the pool, hence using less Chlorine? I have no explanation for it whatsoever. When I was running the pool 6 hours a day with CYA of 40 or so and keeping my FC to CYA ratio in count, I was always using more Chlorine during the day (and passing all slam criteria). Now I run pump less, see some algae on the walls, there is a ton of sun (and it's averaging 29 degrees high during the days) , no CYA, and I'm consuming half of the chlorine. What gives?

 

[Methuselah]

The usual recommendation is backwashing or inspecting your filter media and brushing whilst at slam levels, but I wonder if brushing will further damage the paint.

Was the paint or labor to apply under warranty?

I would suggest never initiating the slam process going forward if OCLT is good accompanied by proper CYA and FC. Especially with calcium hypochlorite.

Looks like you have little choice but to deal with the algae - I'm no expert but I'd definitely think it imperative the filter was 100%, and some trichlor would be among step 1 (along with that SWG if you are decided anyway).

And the brushing ... maybe try a small area first? All seems to be a desperate attempt to avoid draining and repiainting though , I do hope the experts here offer you better thoughts or hore solid advice!

 

[tuxedy]

The paint blistered into small bubbles 1 month after painting. About 1 year after some of them got bigger and popped. Now about 75% of the pool has small blisters, of which maybe 15% of them have popped. I think my guy was painting in the middle of the hottest days despite me telling him not to do so.

We like the look of a pure white pool, my wife doesn't like to see tiles. But no plaster available here. We don't have a SWG.

 

[mgtfp]

When you say your chlorine use has decreased, what is the actual FC level now, and what was it before? How low does FC go before you add chlorine, and how far do you raise it?

Regarding the cloudiness, I suspect it's a combination of algae and your blistering paint. Can you catch some of the suspended particles in a skimmer sock? What is your pipe setup? Do you have a main drain or just a skimmer? And you are just vacuuming manually? How often? No automatic cleaner or robot?

With TA that low, I don't think that the cloudiness is calcium carbonate, as long as your pH is under control. Is there a chance that you have very high sulphate or phosphate levels? We don't usually worry about phosphates in terms of algae food in a sufficiently chlorinated pool, but high levels in combination with high CH can create calcium phosphate scale. Same with sulphate, e.g. from using dry acid. But I'm not sure if these types of carbonates would create cloudiness or just scale surfaces.