New Pebblesheen and scaling

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R

rand18m

0
Nov 2, 2013
13
Texas
My pool finally was plastered ~1 month ago. We began to notice what I feared was scaling. Two dark spots near one of the drains and a white swirl spot on one of the infloor heads. Also short white streaks in the shallow areas. The plaster company decided to hit the pool with a large acid dose and it appeared that that the problem was greatly reduced. All white spots in the shallow area disappeared, the white scale around the head was all but gone and the dark areas was greatly reduced as well. He wanted me to keep the LSI slightly negative and continue. Since that time we have had a terrible time keeping the PH down for a few days. Now the TA has gone down to barely 40 and my CH has gone from 290ish to over 400, and this within a few weeks. The discoloration is beginning to return, and although the PH as drifted up greatly a few nights, we add acid and bring it back down immediately each morning. I have been running the infloor system and wonder if the spill over could be contributing to the increase in PH, plus the wind has been relentless.

Anyway I am concerned about the CH increasing so rapidly. The plaster was installed on a very cold day so I suspect calcium chloride was used but not sure if that's the case or how much. I also don't understand how the scale could be reforming since even though we've had PH drift up to near 8 a few nights, it's been brought back down and the drift has been much less the past few nights.

One more note, the pebbelsheen is one of the lightest colors offered, the aggregate all looks grey to me, at least in the shallow areas where it's easy to see, I am not sure if that's just the color of the aggregate or indications of the same problem.

Also I have had a very hard time determining the CH as "endpoint fading" seems to be a problem. We get a slight purple color (very slight) about 31 drops, basically stays that way until over 40 and nothing you could call blue until 45. Assuming that is correct here is todays numbers. (which is basically what it was last night as the PH didn't drift much)

Ph-7.4
CH 450
FC-3-4
CYA-28
TA-40
Temp-64

Thanks
 
For now, there is little you can do to control the rise in CH....just maintain better control of your pH and there should be no scaling.

I would suggest getting your TA up around 60-70 which may be helpful in stabilizing pH. Regardless, it is important to not let your pH get up into the 8's for ANY period of time.

This will all settle down as your plaster cures but you must stay on top of that process for now.
 
CH will increase significantly during the first month after fresh plaster is applied, and also any time a no drain acid wash is done.

I would raise TA up to about 60, and keep your PH below 7.8. Medium term, doing some water replacement to get the CH level down a bit would be a good idea.

There is no way scaling can happen with your current readings, but presumably TA and PH were both higher earlier, which could have lead to scaling. However, scaling will never be especially dark. Usually it is white or tan.

There are some suggestions on avoiding a faiding endpoint here.
 
Thanks guys, the past few nights the drift has been much less. The large rise in CH had me wondering what's going on, even my plaster guy is a bit confused by such a large rise. In terms of testing I did read your post Jason about endpoint fading, however adding 5 drops of 12 didn't change much oh and I forgot to post my tap CH, which is ~250.

I would also note that we have had at least 7 maybe 8 major wind (sand storms) since this time, the system has had a hard time keeping up and backwashing has been often, although that's mostly because of the tight pressure controls needed to run Paramount system. Doesn't take much of a BW to eliminate all the sand that is being collected. I can only assume that isn't helping the situation.

In the meantime I'll keep the PH as controlled as possible, I do intend to get the TA up to 60 and keep the LSI around -.2ish if possible and see what happens. Let me know if that's a reasonable game plan.
 
As JasonLion stated, scaling will be mostly whitish first, and then change to tan or gray over a long period of time. So the dark spots are probably a different problem from the whitish scaling.

Having not seen any pictures of the pool or seen it in person, so I do not know for sure, but I am guessing that the white "streaks" (as opposed to being uniform throughout the pool) is primarily due to the delayed effects of the acid wash procedure. An acid treatment will cause a slight etching or porosity of a plaster surface, which in time, will likely turn whitish over time. Due to the porosity, the plaster can continue to lose calcium from the plaster (even in balanced water) and dissolve into the pool, as you are currently experiencing, and seeing an increase in the calcium level.

The acid treatment that the plasterer recently performed will remove the whiteness and expose the original color again, but the white streaks may appear again, despite whatever the water balance is. There seems to be a lack of understanding of this problem by some pool contractors. Hopefully however, your whitening problem may diminish in time.

As JasonLion and Duraleigh often advises pool owners on this TFP website, if one maintains the water within their recommended ranges, the water IS BALANCED and there is no need to worry about the water causing plaster problems. There are other issues at play for some discolorations, and not necessarily your water balance. Don't blame yourself.
 
To update after only two days my CH has gone from ~400 to ~510. I'm not sure if new plaster alone can raise the CH that far that fast but some opinions are certainly welcome. Using the LSI I'm in balance but I have concerns, the dark spots, (although small) are certainly real and we are now finding a few small orange spots forming. They look like dust but won't brush.

One thing I need to mention, shortly after filling and the plasterer treated, say three days later, the backwash valve broke. Pentair assured me they were sending another out Fedex that day to a local warranty rep who would replace it, 3-4 days later I finally decided I couldn't wait any longer, I found a simple push pull gate, plumbed it in and began circulating again. Now during this time a lot of sand was accumulated because there was a couple sand storms. I balanced the water and went through the motions of getting the pool clean, i.e. backwashing a couple of times, keeping all numbers tight etc. We have never had any unusual FC usage, just the scaling and PH drift that has occurred (I suspect the scaling started when not circulating for those 4 days). Anyway I'm not convinced this is correct as the aggregate in this very light Pebblesheen seems to be turning darker with of course the exception of the blue aggregate (specs) and in the color. In the sunlight it's all good, without direct sunlight the parts that are concerning are very visible. (one dark spot about a foot diameter) In the night light trowels marks are everywhere. (that could be normal, wouldn't know)
 

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