Calcium levels in replaster

Jump to latest Follow Reply
N

ndakotaninja

0
Nov 26, 2013
118
Elkridge, MD
I got my pool replastered at the beginning of the season. Over the last 2 months the calcium readings have slowly risen from 250 at opening to 525 as of this week. Besides pH levels which rise ~.8 every 2-3 days requiring ~1 gallon of MA each week, the rest of my readings are fine. TA is 70, CYA is 60 (waiting to raise more due to CH levels).

So question for any experts, is the CH raising because of the new plaster, and is that normal? Are there any problems that can arise due to high CH levels? The blue color plaster isn't uniform in color (some areas darker than others), and this week we've started getting very dark spots that almost look like deposits on the plaster. I wasn't sure if that could be caused by high CH or not. If i want to get the levels back down to normal, I'd have to drain 1/3-1/2 of the water, which seems excessive, especially since it's mid-summer and it wouldn't be usable while i drain/refill.

So any suggestions? will it be fine for the season, at which point I'd be draining it for closing anyways? If the high CH levels aren't causing the discoloring areas, any ideas what it could be?
 
High CH can absolutely be a problem. How are you testing? Are you monitoring your CSI? You need to be.

What instructions were you given by your plaster company?

Take care.
 
I'm testing using the TF-100 test kit. I'm not sure what CSI is, so no, i'm not monitoring that. I'm very dissatisfied with my pool company, to say the least. They just subcontracted out all of the work, and don't seem to know much about taking care of pools themselves. I found this out after the fact as I'm asking them questions and their answers directly contradict what these forums and other online pool companies recommend.

The plaster company subcontracted out to the pool company, and the pool company didn't give instructions, so I had to ask for instructions on opening/balancing/cleaning on this forum. Even the basics, like not to add salt or use the heater for 30 days, they never mentioned. I've asked them repeatedly about chemical levels and the discoloration that's getting worse and they have been clueless or said "it happens sometimes, nothing to worry about", but it looks bad and we spent a lot of money on it. So I'm trying to prevent it from getting worse, if it's not normal or if it's something related to chemicals.
 
Here is a picture of the darker discoloration I'm getting, right in the corner area. It's also on the sides of the walls and is coming out in several areas in a 'drip' pattern, like if you took a paint roller filled with paint over a wall and let the extra drip to the bottom. I tried to take pictures of those but with the reflection of the blue skies, it was hard to make out.

It started just in the stair area so i thought maybe just an issue with how they smoothed the stairs, or maybe wasn't being brushed well since it was in the corner, but then it started showing up in a lot more larger flat areas.
 
I don't think I've ever paid attention to that section of Pool Math, so I didn't realize it was there. At my current levels, it says -0.11, which seems perfectly fine.

And yes, in my previous questions regarding startup/pH issues, that was one of the things I read. I followed that during the startup, and it's been open and running for over 2 months now. However it doesn't mention anything about CH increasing over time.
 
Hi Dakota, I would be very curious, too, about the CH - am curious! I have a few questions.

** Did you fill your pool with your tap water (your hose water)? Or did you truck in the water?

** Have you tested your tap water? If you haven't, test everything except for CYA (there won't be any in tap water); then post results. If you have tested it, post the results here.

** Have you needed to top off your pool water with the tap because of evaporation or heavy splash out (lots of kids, parties)? About how often?

** How did the initial brushing period go the first couple of weeks? Any plaster dust when brushing?

** What about when you brush the pool now?

Thanks for taking the time to answer these. They might give us some clues.

Take care,
Suz
 
It is not unusual for CH to rise in a new plaster pool for the first month or so. That CSI is good. Let your TA drop to 60 or 50 to help slow pH rise. Don't run waterfalls, bubbles, etc too much the aeration also causes pH to rise.
 
33,000 gallons, so we got trucks delivered with the addition of the garden hose.
i haven't tested my tap water...are you asking about that purely if i filled the pool with tap water, or do you want me to check regardless?

I think i have run the hose into the pool once this year for a couple hours, then it rained heavily the next day and was over the skim line for a few days. Otherwise, since we filled it the first time, we've gotten enough rain to keep it filled.

Lots of plaster dust when brushing the first week, less so the second and third week. after a month, I vacuumed the pool and got some of the larger chunks sucked up, and haven't seen any sort of dust since then. I've been brushing the lighter areas mostly. It's got a quartz composite added to the blue plaster, so the lighter areas are still as blue as the rest, but are missing the small quartz chips that darken the plaster more. The new really dark areas seem to be the top layer darkening/depositing, rather than something underlaying that's being uncovered as i brush.

I did add calcium when i first balanced the chemicals (a few weeks after replaster, when i set the system up), but since i was only using chlorine (not my SWG) at the time, i used the PoolMath levels for that, so i got it to ~250 CH. So without adding any more since then, it's risen 275 more.
 

Enjoying this content?

Support TFP with a donation.

Give Support
@pooldv, I'm not running any additional aeration, and I'm okay with CH rising over the first few months, but the question is, is going from ~250 to 525 over 2 months normal?

@Foxy, it's a blue plaster composite with quartz addition. I forget the brand, but I can find that out if you want. No, the pool company did not inform me about it not being uniform, and the plaster company (subcontractors) did not say anything to me. And my pool company didn't offer opening instructions, but directed me to a local pool supply store. I found out later (researching) that it wouldn't be uniform, but the darkening areas, especially in the odd patterns, are new and seem like they're not part of the usual 'ununiform'.
 
I thought it was a quartz plaster, but wanted to make sure. I have NPT Quartzscapes that is about 3 weeks old. The common suggestion when you feel there is a problem with your plaster job is to contact the manufacturer, not the pool builder, but the manufacturer of the plaster that was used, so for that you would need to figure out what brand it is. They will send out a representative to take a look and tell you if it's acceptable by industry standards or not, unfortunately it seems that industry standards are low and most of the time they are telling people it's acceptable even if you don't like it. Or if there is a problem, they like to blame it on the water chemistry and if you don't understand the chemistry and aren't testing yourself, it's your word against theirs. You can have your builder come back and look at it, but chances are they are going to tell you its normal, never know unless you try though.
I know it's hard to photograph the areas through the water, but could you try to get pictures of other areas that are changing?

There's some information here Diagnosing Pool Plaster Problems
and here might help Being Blamed for Plaster Discolorations? Don't Get Hoodwinked

Testing whatever water is being used to top off your pool (hose water) will help to know how that fill water is going to affect your water chemistry, test the PH, TA (total alkalinity) and CH (calcium hardness) of the fill water. If your fill water has high CH, then your CH level in your pool will continuously rise. I live in an area with high CH and we have to drain every few years because it will get into the thousands.
I am confused by this part of your post though "TA is 70, CYA is 60 (waiting to raise more due to CH levels)." CYA level doesn't have anything to do with your CH level? CYA (stabilizer) is for FC (free chlorine), TA affects PH.
 
pooldv said:
It varies quite a bit. Did they acid wash the next day and then fill? Or no acid wash?

More here, New Pool Plaster does not always cause CH rise
Click to expand...

No acid wash. They finished, then filled it and i added the acid to it. Interesting post about CH. I tested the water as soon as it was put in from the truck, nothing was out of the ordinary. Original CH was 125, TA 0. Once the acid startup (a week) finished, I raised the pH to ~6.5, added chlorine tablets, and stabilizer (slowly got to ~50), and baking soda to raise TA to ~50. A week later, CH was up to 250. 3 weeks later, 375. A week later, 425. So after a month of running the system, when i got my SWG started up, here were my levels:
pH ~7.5 (was constantly rising, so i was putting ~1qt in a day to keep it as close to 7.2 as i could)
FC - 3
CC- 0
CH 425
TA 70
CYA 50
Salt 3100

3 weeks later, everything was the same but CH was up to 525.

@Foxy, I only added water to the pool once since opening, and it was only for a couple of hours, so I doubt that the water there added to the CH. I'll get some pictures when I can...been raining heavily the past couple of days. What I meant by my CYA comment was I wasn't going to add more stabilizer just yet if I'm going to need to drain 1/4 of the water off. I'll drain things first, then add what I need to balance things out. No sense adding chemicals just to flush them away :)
 
Ok, that explains a lot. With TA at 0 pH is around 4, that is referred to as aggressive water which will dissolve CH out of the plaster and into the water. Also, not acid washing will contribute to the CH increase when the plaster cures. But, the very low pH is the main cause of the CH rise.
 
pooldv said:
Ok, that explains a lot. With TA at 0 pH is around 4, that is referred to as aggressive water which will dissolve CH out of the plaster and into the water. Also, not acid washing will contribute to the CH increase when the plaster cures. But, the very low pH is the main cause of the CH rise.
Click to expand...

So I understand that being the case as it starts curing, but should it still be rising at this point, over 2 months after the systems's up and running when the pH is at normal levels?
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply