Chalky residue on pool sides

[dwstewart]

Hi,

I've been using the BBB method all this season and couldn't be happier. I'm puzzled by a chalky residue that covers the sides of my pool. When you rub it, it comes off and floats as small "dust" particles creating a cloudiness in the water. The pool was repainted this past spring, walls are fiberglass and bottom is concrete.

Any help on identifying what this is and what to do about it would be appreciated.

Dave

 

[Bama Rambler]

Probably paint chaulking.

Post a full set of test results and how you got them.
Also, what does the water look like?

 

[dwstewart]

FC 11
CC 0
pH 7.5
T/A 100
CYA 75
CH 0

Water is clear enough to see bottom drain at 8' but I wouldn't call it sparkling.

FC is coming down from mustard algae shock at 40 due to high CYA.

I didn't add calcium as i didn't expect leaching.

Dave

 

[Bama Rambler]

With fiberglass you need to maintain a certain level of calcium hardness. If your CH is really zero, that will contribute to your problem.

 

[dwstewart]

Everything has a fresh coat of epoxy paint on it so I thought I was good for a season. I can add calcium but any ideas what the chalky residue is? It was not apparent until recently.

 

[Bama Rambler]

You say you're coming off shock. Are you sure it's not just dead algae settling out of the water?

 

[JamesW]

If you rub your hand on the paint, does it leave any white color on your hand?

 

[dwstewart]

Definitely!

 

[JamesW]

Epoxy paint used to be good until they changed the formulation to be more "environmentally responsible". However, the result is exactly the opposite. It is now worthless (in my opinion). The new paint just does not work in a pool. The only way to fix it is to sandblast off the paint and recoat with a more durable coating. You might want to contact a fiberglass pool resurfacing company for proposals.

 

[dwstewart]

I found on another site that if the pool paint is chalking then the total alkalinity is too low and should be raised to 150 or above.

Anyone see any problems with this?

 

[JamesW]

The primary problem is that the manufacturers removed all of the good solvents in the paint in an effort to reduce the amount of volatile organic solvents (VOCs) released during the drying/curing of the paint.

The old epoxy would last for years without any trouble. The new epoxy uses water as a solvent, the very stuff your pool is filled with. If a paint says "Low VOCs" or "VOC compliant", then you can be sure that it won't work.

I don't think it will help much to raise the TA. It might a little, but the high TA is going to cause the ph to continually rise and you will constantly be adding acid to lower the pH, which will lower the TA as well. Then you will add baking soda to raise the TA again and you will end up in a losing battle.

The only way to keep the pH down while maintaining a high TA is to use carbon dioxide to lower pH.

Another warning sign of bad paint is the term "easy cleanup". It cleans up easily because it's weak, water-based paint. The label should say something like this:

This paint is blue; whatever it gets on is going to blue forever. Forget about cleaning it off of anything. Just throw the brushes, rollers and trays away because you're never going to get them clean, ever, seriously.

 

[dwstewart]

It's good paint-- best available, not water-based. Chalking was apparently caused by "harsh shocking" and low alkalinity. It is recommended that keeping the alkalinity on the high side (175 ppm) helps prevent chalking. Since this is above the troublefreepool recommendation I was asking if I should be concerned about any consequences from maintaining such a high alkalinity.

 

[Beamup]

James described the highly undesirable consequences - your pH will keep increasing very fast. You will then need to add lots of acid to keep the pH under control. Which will decrease the TA so you have to add even more baking soda.

I suppose it would be POSSIBLE to maintain TA that high, but it would be a lot of work and consume large amounts of acid and baking soda.

 

[ghgh]

I have had the same problem with my pool. Painted my plaster pool two years ago with Ultra Poly One Coat. First summer was fine, but second summer a disaster. Water became cloudy from chalking and paint on bottom was coming off on people who were in the pool. We were not able to use the pool for the entire summer season. I did try to resolve this with the company but they were only will to replace the paint, not refund the purchase price. I certainly didn't want anymore of their paint products. Now the pool will have to be sandblasted and replastered.I really thought I had done my homework before purchasing this product but obviously not enough. You will save yourself time and money by not purchasing this product.
ghgh