Are these nodules?

[bc1]

Hi there,

Looking to get some input on if these are calcium nodules. They look like "drips" and don't come off easily with brushing. They started showing after the last winter season in which I didn't do the best job keeping the chemistry in balance. I'm sure the pH was quite high for several weeks. Below are some water numbers from a few months ago vs today.



Today
FC: 3.4
CC: 0
pH: 7.0
TA: 100
CH: 330
CYA: 40

January
FC: 7
CC: 0.2
pH: 8.0
TA: 102
CH:228
CYA: 0

FYI- I'm trying to lower my TA with aeration (just started today) which is why my pH is down to 7.

Thanks!

 

[YippeeSkippy]

Hello! Here's the first problem- those test results aren't looking like they've been done with a test kit I'm familiar with. Are they from a pool store?
One of the posters here is an expert cement researcher and this is an article he wrote about Calcium Nodules. See if it fits your issue?

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...

www.troublefreepool.com

Maddie

 

[YippeeSkippy]

TA does not lower with aeration. Aeration is the trick we use to Raise pH. TA is only lowered with Muriatic Acid, which also lowers the pH. So then you use the aeration to raise just the pH but the TA remains low.

 

[bc1]

Yes, the results from January are from the local pool store. I do have the Taylor K-2006C kit which I used to measure the results from today.
I'm following the Pool Math instructions to lower TA which is what you're describing. I was trying to explain why I had a low pH reading (it was after adding Muriatic Acid) but misrepresented the cause/effect.

I read through that post you linked ahead of posting and it did seem similar to what I'm noticing. I am hoping to see if there was a definitive way to confirm it is not anything else and see if anyone had a relatable experience.

 

[YippeeSkippy]

Since your test results are using 25cc pool water to test, cut it back to 10cc pool water. That way each drop of 0871 reagent is valued at 0.5ppm. Or to be easier- you just have to count the drops and divide by 2. It also saves reagents by only using 10cc sample of those two tests.

I couldn't see what your photos were showing, which is obviously hard on different screens. Do you know how old your plaster finish is? Did you only just now see them and they weren't there before? Or did you move in and they were already there?