Scale or some other plaster mix issue?

[PfTXPoolDad]

I’m wracking my brain trying to figure out what this is. Pool PH has been kept solidly between 7.6-7.8 since fill. Occasionally I was able to get it down to 7.2-7.4 but that only lasted a day.

The streak by the jet is slightly raised, I haven’t tried scraping it yet.

What should I try to remove it?

Thank you!

 

[ajw22]

When was the pool plastered?

This a new build or a replaster?

Scale does not form in such a localized area.

More likely calcium nodules.

Calcium Nodules in pools What are calcium nodules? In swimming pools and spas, they are small mounds, bumps, deposits, or “slag” piles of calcium carbonate which are formed from material that has been released from the plaster. The small calcium nodules are rough to the touch, hard, and generally gritty. Nodules may form singularly (far apart or sporadically), or many and close together along a crack in the plaster surface.

 

[PfTXPoolDad]

When was the pool plastered?

This a new build or a replaster?

Scale does not form in such a localized area.

More likely calcium nodules.

Calcium Nodules in pools What are calcium nodules? In swimming pools and spas, they are small mounds, bumps, deposits, or “slag” piles of calcium carbonate which are formed from material that has been released from the plaster. The small calcium nodules are rough to the touch, hard, and generally gritty. Nodules may form singularly (far apart or sporadically), or many and close together along a crack in the plaster surface.

Interestingly this is a new build which we completed in February, and had to replaster because we discovered hairline fractures everywhere during acid acid wash.

Assuming you’re right, what’s the best way to solve this? I don’t think I see new ones forming - it’s just I’m finally out there enough to see it when the water is still.

 

[ajw22]

You have a form of delaminating with the new plaster not adhering to the surface below.

There is no fix for it other then a full chipout down to the gunite and bonding coat and new plaster. Or you live with it. You can sand the spots smooth using 80/100 grit sandpaper whenever they come back.