There's Too Much Calcium In My Pool And The Water Is Cloudy

We used chlorine with a lot of calcium in it. Now it's cloudy and I don't know how to get it clear.

Please give me some suggestions on what to do and also is it safe for us to swim when all the other chemicals are perfect except for the calcium.

Thanks for the question

Chlorine granules, called calcium hypochlorite, should only be used where the fill water has low hardness. Here in Oregon our fill water is about 1 - 2ppm hardness. In Arizona, where I had my pool route, the hardness could be 300 - 400ppm, so I used mostly liquid chlorine (sodium hypochlorite).

My suggestions would be to stop using granular chlorine and start using liquid. There's no easy way to reduce the hardness of the water other than drain 1/3 - 1/2 of the pool water, refill, and balance out the chemicals again.

The main danger to having high calcium is scaling. This is when a nice little white ring forms at the water line. If your pool is heated, the high calcium level might clog up the heater. You can also have scaling in the pipes, plumbing and filter. With extremely high calcium, the water can become dull and cloudy.

For a salt pool, it's damaging the chlorine generator. The safest way to remove the ring is with a pumas stone or a wire brush. You can also do a muriatic acid/water mix. A 3:1 mixture works well. Take a sponge and rub the acid mix onto the buildup, then use the stone or wire brush.

This should not be done on a vinyl liner as the liner might tear. If all the chemical reading are fine, you shouldn't have any issue in clearing up the pool. Keep filtering 24/7 until it does clear. Shocking the pool won't do anything. I would like to know what the calcium reading is.

A couple of things that can happen to swimmers is itchy, dry skin and sore, red eyes. Once you get the hardness out of the water, your pool will be just fine. Hope this helps and have a fun and safe swimming season.


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Calcium Hyperchlorine Shock Dose Instantly Turned Concrete Pool Surface Black!

by Bill
(Buderim, Queensland, Australia)

I added 4kg of calc hyperchlorine to shock dose a 35000 liter pool and it instantly turned concrete pool surface black.

The pH was 7.2 at the time. What caused this reaction? What can I do to get it right?

(I added this to get rid of Black Algae, which I cannot get rid of. Any ideas on the black algae?)


Thanks for the question Bill

I believe this is copper sulfate stains that oxidize from a shock using calcium hypochlorite that sits directly on the copper stains. You can avoid this by using liquid chlorine as your shock.

Have you had your water tested for metals and/or do you use an algaecide that has cooper it in?

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper). It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

Be sure that you have black algae and not metal staining. This is very easy to do.

Get a chlorine tab and put it in a sock. Put the sock directly on a black spot in the pool for about 15 - 20 minutes. Use a telescopic pole to hold it in place.

If the stain fades, it's black algae. You can go to these links on how to get rid of black algae:

Black Algae

Basically you'll need to shock the pool and scrub the spots with a wire brush. Black algae attaches itself to the plaster in layers. This is why it's one of the hardest to remove. It can be done, I've personally done it, but it can be a pain.

If it doesn't fade, get ascorbic acid (crushed up Vitamin C) and put about 1/2 lb. in a sock and put that on the spot for 15 - 20 minutes.

If that fades it's a metal/mineral staining problem and can be solved with an ascorbic acid treatment. This page has the ascorbic acid treatment:

Brown Algae Won't Come Off Of A Vinyl Liner

Some say to use an aluminum sulfate after plaster turns black after a shock, but this is basically a flocc, which is supposed to clear up a cloudy pool. I'm not a big fan of floccs because they're expensive and it doesn't address why the pool is cloudy is the first place.

Hope this helps and good luck with your pool.


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Fine White Dust

by Anthony

I recently had my pool re-plastered in December and had it recently drained and acid washed due to rust colored markings that I later learned Magic Jacks 2 actually removes quite well.

The issue I am having now is a fine white plaster dust that becomes stirred up when I brush the pool or when someone walks on inside the pool. The pool is generally clear but you can see the lines and patterns of the dust sitting on the bottom of the pool. Is there anything I can do to get rid of it?

Thanks for the question Anthony

I'd like to have your complete chemical readings, the actual numbers:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. It makes troubleshooting much easier and the process of clearing up your pool will go much faster. What you may have is a symptom of a problem. I also need the kind of filter you have and if it's working properly. If it's not working it must be fixed in order to clear up the pool.

Next I would ask if you're using calcium hypochlorite to chlorinate your pool. Calcium settles to the bottom and can mimic plaster and clouding in the pool. Too much calcium chloride can also cause a thin layer to form on the bottom.

Whenever an acid wash is done it actually removes a layer of calcium carbonate from the surface. This may be happening and might continue until it settles and cures a bit.

If the filter is not filtering properly then all of the debris is going back into the pool.

If you feel your situation is more complex than this, I do phone consultations for a donation of your choice. It makes things go much faster and many people have found it extremely beneficial, saving them time and money in the long run. All your questions will be answered. I have nothing to sell you so you know I'm not bias.

Pool Consultation

Hope this helps and have a great Summer.


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Large Black Stains On Concrete Bottom

by Nancy
(Longwood, Florida)

I was told at the pool store to add 2 bags of super shock granular to the deep end of the pool while the pump was running and without pre mixing as it said on the bag. The calcium hardness was 225, ph was 7.4. I only broadcast one, 1 lb bag in and it was fine white powder sinking, HOWEVER, when it got to the bottom, it formed a huge ugly patch that looks like a giant manta ray in the deep end! What do I do now?

Hi Nancy. What probably happened is the cal hypo precipitated metals in the water. Metals can be from well water, use or over-use of copper algaecides, heater coils, or some kind of combination. This is one of the main reasons why no pool owner should ever use a copper based algaecide. Get your water tested for metals. If it comes back positive you're going to need to do some things.

First is to get a metal sequestrant with the ingredient 1-Hydroxyethylidene-1, 1- diphosphonic Acid, a.k.a HEDP. Jack's Magic has a good line. Try to lower the pH to 7.0 after adding the sequestrant and see if the stains lift. If they do then you'll have a couple of short and long term solutions. Short is to keep adding the sequestrant until the metals in the water are gone. Long term is to replace all or the majority of the pool water with new water that doesn't have metals.

If adding the sequestrant doesn't work and you're positive they're metals stains, you'll need to do an ascorbic acid treatment. AA is nothing more than crushed up Vitamin C. This should remove the stains from the pool surface. You can find the procedure in this link.

If you choose the AA treatment, it's important to go slowly, get the pH to 7.0 (no higher than 7.2), use a PolyQuat 60 algaecide during the process, slowly add the chlorine back when the stains are gone, and don't shock the pool for at least 2 weeks. You may go through several gallons of chlorine to bring the FC level back up. Remember you have AA in the water so whatever chlorine you add will be eaten up by the AA. Keep adding chlorine and testing once per day until the FC holds. If you're the least bit hesitant on doing this procedure, it's best to call in a qualified pool tech. You're in FL, as I am, so there's virtually no reason at all to use granular chlorine. Only use liquid.

Of course, some situations are unique and yours may very well fall into this category. If this is the case, I would be happy to spend the time necessary to address your concerns personally through a consultation. Consultations can be done via telephone or Skype, whichever you feel will meet your need the best. I only charge $37 for this service in an effort to make pool ownership affordable and understandable.

Pool Consultation

Clear Blue Pool eBook

How To Clear Up A Green Pool eBook

Swimming Pool Resources


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