How long should I wait to add Salt and start the SWG after re-plastering with colored plaster?

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sailor21
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How long should I wait to add Salt and start the SWG after re-plastering with colored plaster?

Postby sailor21 » Fri 12 Feb, 2016 07:29

Hello!

I just re-plastered my pool with Blue Quartz and my Pool Guy recommends to run the pool with chlorine for about 3 weeks before adding salt & starting the SWG.

He does not have a specific reason why and, when he has asked his peers, no one can come up with an answer other than "That's what the Manufacturer requires".

Has anyone experienced any issues when adding salt too early?

Appreciate the feedback.

S21


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Larry
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Re: How long should I wait to add Salt and start the SWG after re-plastering with colored plaster?

Postby Larry » Fri 12 Feb, 2016 11:51

Hi S21

Waiting 3 weeks is recommended and the science as explained by OnBalance is as follows:

The results obtained suggest that adding 3000 ppm of salt does indeed have a negative effect even on good quality plaster if added at startup and up through the first two or three weeks. When salt is added to water containing fresh plaster coupons, the pH of the water began to increase significantly (higher than normal). This indicates a loss of calcium hydroxide from the plaster surface is occurring. This likely causes an increase in the porosity of the plaster finish, which weakens and ages the surface prematurely.

The data also indicate that the negative effect of salt on new plaster only lasts about three weeks. As mentioned above, this is because a new plaster surface becomes carbonated; meaning that any calcium hydroxide (on the plaster surface) that is not dissolved and converted to water hardness and/or plaster dust is slowly being converted into calcium carbonate during the first three to four weeks of being filled with balanced tap water. This conversion creates a protective and more durable plaster finish. It appears that once the plaster surface has been sufficiently and properly carbonated, salt does not have the same negative effect.


The full text report is here for your reference.

Larry

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