2 years after replastering… Calcium high and dark stains

[MeSue]

We had our pool replastered 2 years ago and we have been getting a lot of white residue in the water. I finally got around to testing my CH and it is quite high. From what I am reading, the only way to lower is to replace water? Here are all my numbers:

FC 8
PH 8
TA 130
CH 870
CYA 60
Salt 4800
CSI 0.84

My tap water CH is 170.

What do you advise?

Another thing we noticed last year, about a year after the replastering, were several stains that look like smears. I tried SLAMing last summer and it didn’t affect them. I tried pumice stone, and brushing, and that doesn’t take them off either. When they replastered the pool, the workers spilled a bunch of plaster in our yard. We suspect after they scooped it up, they reused some of it. I don’t know if that would cause these stains or what. Sigh. Not sure there’s anything we can do so long after the job was done but the stains did not manifest until much later. Any thoughts on this?

 

[kul]

To lower calcium water needs to be replaced. You can do a drain/refill, no drain exchange or RO.

 

[PoolGate]

You water parameters are all off. CH should be like 250. Only a water change is going to fix that. Your TA is also very high. CSI is also high. Salt is also high. Who maintains your water?

 

[jesse-99]

Any pictures of the dark stains?

That would suck if they spilled it and still used it, who knows what gunk got mixed into it. OTOH, my plasterers added plaster to my grass, to my trees, to my mulch, and to my stones for drainage, on my pool tiles, etc. but hey, at least they didn't reuse the stuff they dropped or dumped everywhere, ha.

 

[MeSue]

You water parameters are all off. CH should be like 250. Only a water change is going to fix that. Your TA is also very high. CSI is also high. Salt is also high. Who maintains your water?

I do! My SWG calls for ~4500 ppm salt, so I overshot a little the last time I topped it off.

Is the replastering why CH has crept up so high? I never used to have a problem with it.

 

[MeSue]

Any pictures of the dark stains?

That would suck if they spilled it and still used it, who knows what gunk got mixed into it. OTOH, my plasterers added plaster to my grass, to my trees, to my mulch, and to my stones for drainage, on my pool tiles, etc. but hey, at least they didn't reuse the stuff they dropped or dumped everywhere, ha.

I tried to get some pics last summer but they didn’t turn out. I’ll try again. Yeah the company owner was okay but his crew really sucked.

 

[MeSue]

Is CH of 870 and/or the white residue a problem? What I’m getting at is… how urgent is it to do a water replacement. I’m in Florida so there going to be some naturally when the rainy season starts.

 

[PoolGate]

Is CH of 870 and/or the white residue a problem? What I’m getting at is… how urgent is it to do a water replacement. I’m in Florida so there going to be some naturally when the rainy season starts.

You are over the max. Biggest issue with high CH is your SWG may start to get calcium deposits on it. It can also cause scaling on the plaster.

Have you calculated your CSI? That is the overall calcium saturation index.

Calcium Saturation Index (CSI)

CALCIUM​

ACCEPTABLE MINIMUM:​

250-350

IDEAL:​

350-550

ACCEPTABLE MAXIMUM:​

550-650

 

[MeSue]

You are over the max. Biggest issue with high CH is your SWG may start to get calcium deposits on it. It can also cause scaling on the plaster.

Have you calculated your CSI? That is the overall calcium saturation index.

Calcium Saturation Index (CSI)

​

got it. Yes… CSI is in my original post. 0.84 according to PoolMath with my numbers. I will do the water replacement because we have been getting a lot of buildup on the SWG cell and then it deposits the white flecks in the pool.

 

[MeSue]

Just to follow up… We drained about 3/4 of the water, refilled, and rebalanced, which brought the CH to about 240. Then we discovered the SWG cell had a crack in the end cap that was leaking, so we had to replace that (cell was barely a year old and under warranty—great service from CircuPool). Water was a little yellow for a couple days after refilling with well water but it cleared and the pool is beautiful now. No more white flakes accumulating on the steps! Hooray!

Regarding the dark stains… I never managed to get pics, but when we drained the pool, we discovered they were areas where it appeared mineral deposits had seeped through the plaster. Where it happened on the sides of the pool, they looked like thick drips that oozed from the side of the pool—like something you’d see in a damp cave. On the floor of the pool, it created rough “smeared” areas on the bottom where fine dirt would accumulate, so they almost always looked dark. My husband scrubbed all these spots with a stainless steel brush and now they are much less obvious. There is still slight roughness in some spots so we continue working on them with the wire brush.

My questions are… is this mineral seepage something typical after replastering? And how long does it last? Is there a chance it will keep happening?

The company that replastered did the after-care for 10 days and after that I followed the brushing instructions I was given but he didn’t mention anything about this potentially happening and I have never read anything about it. Just curious…

 

[MeSue]

Been a month since draining. CH has crept up to 400 from 240. The mineral deposits have come back and there are now more than there were before. I now understand to be calcium nodules after doing some research here. Thank you so much for the informative post!
Thread 'Calcium Nodules in pools'
Calcium Nodules in pools

We will be contacting the company that did our replastering soon. Fingers crossed!