Pool pebble surface blotchy spots from high chlorine? Builder says my fault-need help

[oldguy70]

Had my pool resurfaced in March 2015, about May-June seemed to notice color was uneven, blotchy areas, called builder, finely in early August he came out took pictures and (6 months later) returned today along with the builder was the gunite/pebble supplier and the owner of the crews that did the work....the gunite.pebble guy said that the pool has been over chlorinated causing the pool to bleach out in those areas.

The areas have not gotten any worse since May-June...just looks kinda blotchy not an even color (will try to post pictures).

I am not trying to get something for nothing here, I made it clear with the builder, if this was any way my fault I will pay to fix it, I need someone here that is familiar with this type of problem. Makes sense maybe me trying to hold my Chlorine high because of high CYA created an additional problem of bleaching out the pebble color.

I also want to say, yes I am very aware of high CYS reading, before this coloring issues, plans were to get the CYA back down to a more reasonable number, my fault as I started using tabs, until I was educated by you guys and switched to liquid....

During the summer with water temps at 90, I tried to hold my readings @ Tested every 1-2 days
TC 10-12
CC 0
pH 7.5-7.6
TA 95-100
CH 400
CYA 120-150

If anyone can give me insight here would be much appreciated...thanks

 

[oldguy70]

 

[ewkearns]

You are probably going to be "talking to the hand" on this one. It is unlikely that your builder(s) will recognize the chlorine/CYA relationship and, frankly, even if they did, your chlorine is way high. IMHO, your chlorine should have been more like 5-6 ppm instead of 10-12, but had you done that, with a CYA of 120-150 your pool would probably have been green.

Your pool builder should have given you "Recommended levels of [whatever]" for you to follow during the curing process and IMHO, you should have followed them, anticipating the possibility of a warranty claim.

Outside of the warranty period, it is yours to do as you see fit..... I think this one might end up being "on you" unless they never told you what was prohibited.

These are the very basic guidelines we offer, here....

http://www.troublefreepool.com/content/134-recommended-levels

 

[oldguy70]

I posted these 2 pictures....the Gunite/Pebble guy pointed out the light color on the first step being bleached out from the popup head cleaner with high chlorine....he also chipped at an area in the skimmer to show me how 'blue' under the chipped area the color is.

I just need to know, if my high chlorine caused this bleaching/blotchy of my pebble color, then I know this is on me not the builder......just seems if this was the case then it would be happening to a lot of others, and the pebble guy said he had only one other pool where this has happened.

 

[ewkearns]

IMHO, the answer would be yes, since I'm assuming from your high CYA concentration that you have been using granular chlorine. If not, I'll defer to those with more plaster experience.

 

[oldguy70]

IMHO, the answer would be yes, since I'm assuming from your high CYA concentration that you have been using granular chlorine. If not, I'll defer to those with more plaster experience.

Used tabs for the first 60 days, until I found TFP, switched to liquid chlorine for the past 10 months, have done a few small drain/fills to try to lower the CYA.....never gave a thought that high chlorine would or could cause bleaching of the pebble, which has gotten no worse over the past 9-10 months....and I would have thought if the high chlorine with the popup Caretaker cleaning heads the area closest to those heads would bleach out the worst, not the case.

 

[pooldv]

It is possible that there is an issue with calcium scale. Also, don't hesitate to get the manufacturer involved Pebbletec or whomever it is. Most are happy to help resolve customer issues.

 

[bdavis466]

A chlorine level of 10-12 with a CYA of 120-150 roughly equates to 0.05-0.12 ppm of chlorine with no CYA. This is no worse than any plaster or pool equipment manufacturer's recommendations, in fact it is far less harsh. That damage is not from chlorine as that would be very difficult to happen with CYA in the water.

Chem Geek posted below on a pool with a CYA of 150 and 11-18 ppm of chlorine.

At 80ºF in a pool, it's more like 0.08-0.14 ppm FC with no CYA.

If you used granular chlorine and threw it in the pool and let it disolve while sitting on the plaster, then the damage was more from an acidic source of stabilized chlorine, not the chlorine itself. The plaster looks damaged from low ph. How do you add acid to thge pool?

The pool industry as a whole does not recognize the FC/CYA relationship presented here on this site nor do they understand the buffering effects of CYA in general. This will undoubtedly be a losing battle for you since the water perameters were maintained so far from their guidlines, even though no harm would be done with the levels you maintained.

 

[oldguy70]

If you used granular chlorine and threw it in the pool and let it disolve while sitting on the plaster, then the damage was more from an acidic source of stabilized chlorine, not the chlorine itself. The plaster looks damaged from low ph. How do you add acid to thge pool?

For example if I add 10 ounces I would add acid...pouring slowly 2-3 ounces at a time going around perimeter of pool with the pump running for at least 2 hours to mix well. The in-floor Caretaker heads seem to do a good job of moving the water.

 

[bdavis466]

Did you ever use algaecides or a mineral cartridge? The plaster looks more stained than bleached to me. What happens when you brush it?

What pH do you typically maintain?

- - - Updated - - -

Have you tested your water for metals?

 

[oldguy70]

Did you ever use algaecides or a mineral cartridge? The plaster looks more stained than bleached to me. What happens when you brush it?

What pH do you typically maintain?

Have you tested your water for metals?

No algaecides or other additives....ph 7.5-7.6

When new-brushed twice a day for a month lots of concrete dust, now every 2-3 weeks - No concrete dust - actually nothing when brushing now, pool stays very clean.

I have taken water samples to pool store, I don't think think can test for much....local water has no iron, and I have adding nothing other than chlorine, acid, and some baking soda, really don't know, if there is specific metals to test for that would cause the blotchy coloring.

- - - Updated - - -

It is possible that there is an issue with calcium scale. Also, don't hesitate to get the manufacturer involved Pebbletec or whomever it is. Most are happy to help resolve customer issues.

Would calcium scale show elsewhere? On tile water line? Have some light deposits on grout between the tiles, which seems normal, don't know?

 

[bdavis466]

How did you add baking soda? Was calcium ever added?

 

[wjr75]

I wonder if an acid wash would even things out. You had indicated he had scrapped by the skimmer to get a fresh blue color.

 

[oldguy70]

How did you add baking soda? Was calcium ever added?

Used BakSoda to adjust TA...I have added NO other items, just Chlorine, Acid & BakSoda (used tabs for the first 60 days as I have mentioned)

- - - Updated - - -

I wonder if an acid wash would even things out. You had indicated he had scrapped by the skimmer to get a fresh blue color.

They discussed that, the pebble guy took a gal of acid on the top step and held it upside down slowly pouring in one spot for several minutes just above the surface until empty and proclaimed it had no effect and draining and acid washing would not do a thing as the surface has been bleached out by over chlorinating, then chipped out a small area inside the skimmer to show me that the color was there, but the surface areas were bleached out.

 

[pooldv]

Here is more on calcium scale, Pool School - Calcium Scaling

Here is a thread about removing scale by richard320, Progress on scale

 

[oldguy70]

Here is more on calcium scale, Pool School - Calcium Scaling

Here is a thread about removing scale by richard320, Progress on scale

No, its not scale

 

[bdavis466]

In the pictures the discolorations look yellow which is why I suggested staining. Scale is often more of a whitish/grey color and your numbers are not suggestive of that.

Most pebble installers add calcium chloride to the plaster mix to allow the surface to set up quicker for troweling and spray washing. The problem with this calcium addition is that it weakens the plaster and is VERY prone to making darker colored plasters mottle and discolor. This may very well be what you are experiencing.

I understand why they are blaming the high chlorine level for the "bleaching" effect but that is simply not possible with the CYA level you have in the water.

 

[oldguy70]

In the pictures the discolorations look yellow which is why I suggested staining. Scale is often more of a whitish/grey color and your numbers are not suggestive of that.

Most pebble installers add calcium chloride to the plaster mix to allow the surface to set up quicker for troweling and spray washing. The problem with this calcium addition is that it weakens the plaster and is VERY prone to making darker colored plasters mottle and discolor. This may very well be what you are experiencing.

I understand why they are blaming the high chlorine level for the "bleaching" effect but that is simply not possible with the CYA level you have in the water.

bdavis....I guess you had asked how I added Baking Soda, I broadcast around the pool...also may I ask what is your expertise on what you have said here, it makes sense to me, but I guess what I am saying is I need a expert foundation to argue that the CYA buffered the high chlorine and in no way could bleach out the pool. Even with that it may be a lost cause. Either way, I need to know for certain what caused this and correct it.

 

[bdavis466]

There is much science on this forum to backup the FC/CYA relationship but as I mentioned before, it will be falling on deaf ears. The pool industry does not recognize this relationship and will likely be (and were) appalled when they saw a FC level of 15.

Chem Geek (Richard Faulk) is the resident expert on the FC/CYA relationship and is responsible for much of the research and understanding on the topic (the main premise behind this site). He has tirelessly devoted much time to educate the pool industry on this simple bit of knowledge but even he had limited success. He has not been around in a good amount of time, which is unfortunate since he could easily show the research to back my previous statements.

OnBalance is the plaster expert on this site. Perhaps he could provide some insight on what he feels may have happened but I still don't think that will help your cause.

There are several more experts on this site but keep in mind that this is a forum for homeowners to manage their own pools. Nothing more than sympathy can be offered to you since the plaster company has already showed you their hand and since the water was maintained outside of their recommendations, I don't know that you have a leg to stand on.

 

[jmastron]

For example if I add 10 ounces I would add acid...pouring slowly 2-3 ounces at a time going around perimeter of pool with the pump running for at least 2 hours to mix well. The in-floor Caretaker heads seem to do a good job of moving the water.

I actually think it's better to pour all of the acid slowly in front of one return than to broadcast it like this. When you pour directly into the return stream, the acid is immediately pushed away from the walls and diluted quickly into the center of the pool. When you pour away from a return, even with the pump on the acid spends more time concentrated near the wall/floor until the natural circulation dilutes it.

Plus, staying in one place means less risk of slipping/spilling (I always seem to be adding acid and chlorine when it's dark and the Irish Wolfhound is "helping", so walking along the pool edge with an open cup/bottle of acid makes me shudder)