New Pool, Grey Spots

[flyboy789]

New pool build here, plaster and fill was done on December 13th. Pool builder did an acid startup - did not follow NPC start up procedures against my will. Added salt on day 3 - again... against my will. I got the excuse "we build 300 pools a year and this is how we always do it" - One day 4 they handed over the pool to me and were done with it.

I've tested almost daily for the first few weeks then 3-4 time per week. Logged most of the test results. Other then going through about a gallon of acid a week to keep the PH down I haven't had to add anything else. Tested for metals in my fill water - none. Also at the pool builders request I'm maintaining the pool at 10ppm of Jack's Magic "The Purple Stuff"

About two weeks ago I got a few light grey spots on the steps in the spa. Tried rubbing with a chlorine tab - no change. Aggressive brushing - no change... Set the SWG to 100% for a few days and brought up the FC to 10... no change

Now they are getting worse - all over the steps and floor. Nothing on the vertical surfaces though.

Current levels -
FC - 4
PH - 7.6
Alk - 110
CH - 230
CYA - 90[
Salt - 3500

Does this look like a plaster issue or algae? Spots are about dime/nickel size

 

[JamesW]

Can you pull the cartridge out of the filter and post a picture?

Looking to see if the cartridge has a turquoise color that would indicate copper or other colors that might indicate other metals.

How much acid was added for the acid startup?

Was water running through the system during the acid startup?

Try putting ascorbic acid (vitamin C) on one of the spots.

Looks like the heater has a titanium heat exchanger. It should be fairly resistant to low ph, but I don't know how much it might be affected.

 

[flyboy789]

I pulled the cartridge last weekend, looked fine to me. Ill pull again tomorrow morning.

Pool store report says they tested for copper and it was 0 - if they really did, I don't know.

Startup -

Day 1 - Fill
Day 2 - Pump on - 3-4 gallons of acid - Jug of Chlorine
Day 3 - Salt & Baking Soda
Day 4 - They were done with it... never came back again for followup.

As you can imagine - I was NOT happy with their startup procedure.

Should I SLAM to rule out a possible algae issue?

 

[JamesW]

I suspect that it's metals. A Slam might precipitate them if that's what it is.

I would suggest a bottle of sequestrant and a bottle of poly 60 algaecide (just in case it's algae related).

Brush well and filter continuously for a few days.

Maintain good chlorine levels, but not too high.

If it's metals, it will usually be evident in the color of the cartridge.

Also, crush up a vitamin C tablet and sprinkle it on a spot to see if it makes any difference.

It might be manganese. Are you using well water?

Maybe titanium, but I don't know how likely that would be or what titanium stains would look like.

It would probably be worthwhile contacting the plaster material manufacturer to get their advice. They probably provide some sort of warranty and should be aware of the startup.

 

[JamesW]

Further information indicates that it's not likely to be titanium.

Did the spots begin shortly after the SWG was started?

They really should not have added salt this soon.

 

[flyboy789]

Thanks for the help JamesW!

I have 10ppm of "The Purple Stuff" in the pool and have used it since the first week. Should I use an additional sequestrant?

I will post some pictures of the filter tomorrow as well as try the vitamin C. I'm on city water.

As for titanium... the heat exchanger on my heat pump is titanium???

I will definitely be emailing the pictures to the pool builder for advice and maybe reach out to the plaster company.

Thanks again!

- - - Updated - - -

Further information indicates that it's not likely to be titanium.

Did the spots begin shortly after the SWG was started?

They really should not have added salt this soon.

I agree, argued with them over the salt multiple times. They insisted "we build 300 pools a year and we know what we are doing"

SWG was started day 3 - spots started appearing a month later.

 

[JamesW]

I think that the heat exchanger is titanium.

Titanium is pretty corrosion resistant, so it's probably not titanium causing the stains.

Also, try putting some muriatic acid directly on a spot. Maybe get some in a baby oral syringe and squirt a little bit on a stain.

Just be extra careful as full strength acid is very caustic.

 

[flyboy789]

Pictures of the filter...

Notice where I scraped off some of the film to show the original color.

So copper? Maybe Iron?

 

[JamesW]

I think that the plastic/rubber of the top and bottom are just deteriorating. However, that usually takes a long time. It indicates aggressive chemistry.

The main thing is that the polyester fiber of the cartridge is white. It does not show any signs of high metals.

So, I’m leaning against it being metals, but I don’t know what it could be.

I don’t think that it’s algae.

Did you try the ascorbic acid or the direct muriatic acid?

Maybe the plaster manufacturer can help.

 

[flyboy789]

Did you try the ascorbic acid or the direct muriatic acid?

Maybe the plaster manufacturer can help.

Muriatic acid - no change
Ascorbic acid - no change

Waiting the hear back from pool builder.

 

[JamesW]

Iron will generally stain the cartridge fibers brown. Copper will usually stain the cartridge fibers turquoise. Neither color is evident in the fiber. I don’t think that it’s copper or iron. Also, the stains don’t look like copper or iron.

Other metals might be possible.

Titanium could come from the heat exchanger or cell blades, but I would consider that very unlikely as titanium is very corrosion resistant. Something extreme would have to occur to get the titanium into the water. Excessive water flow through the exchanger might do it. Strong electrolysis from strong stray current/voltage might do it. I would consider titanium to be very low on the possibility scale. You do have an Intelliflo, if you ran it at full speed through the heater, it might be an issue. Excessive flow rates can erode metals from an exchanger. If the salt cell is before the heater, that might cause an issue.

Ruthenium coats the cell blades, but that is unlikely to come off.

Zinc is in some algaecides and in some in-line anodes.

Silver is in some algaecides.

Manganese is in some water supplies.

All water from natural sources contains various metals to some degree. All water suppliers have to monitor and report water quality metrics. You can check recent reports to see if they indicate any high levels of metals.

Most metals will react to ascorbic or muriatic acid.

Overall, really not sure what it is.

 

[JoyfulNoise]

Can you go underwater and look at them or feel them? Do they feel or look raised? Do they look or feel like they have any relief to them?

I wonder if the plaster creme has for some reason spot etched in those areas thus exposing more aggregate. That would certainly make the area look darker.


Sent from my iPhone using Tapatalk

 

[pooldv]

Here are some discussions on plaster discoloration from an industry leader

Diagnosing Pool Plaster Problems
Being Blamed for Plaster Discolorations? Don't Get Hoodwinked
How White Pool Plaster Turns Blotchy
How White Pool Plaster Can Turn Gray
Gray Mottling Plaster Discoloration

 

[flyboy789]

Thanks to all for the comments. The more I read and the more research I do I'm leaning to some type of black algae. The spots first appeared on the bench in the spa. Given that the spa has gotten almost daily use that would make sense that It would grow faster in the spa, then it started to appear on the tanning ledge. I'll also note that my CYA has been way to high. I'm measuring 90-100 with the K-2006 and the pool store is testing at 100-110. I'll also note that I've never added CYA - these levels are from the initial dose done by the pool builder on day 2 of startup. I've drained/refiled probably 25% already just to lower the salt level because my salt was way to high after startup. So for all I know the CYA has been well over 100 for the past month... and my FC has been maintained around 2-3 - Givin the high CYA and low FC algae growth makes sense. I'm planning on doing a partial drain to get my CYA down anyway. If I drained the spa and dumped chlorine directly on the spots for an hour or so is that going to hurt the plaster?

 

[pooldv]

That doesn't seem like black algae. More about black algae here, Pool School - Black Algae

If trichlor pucks or dichlor "shock" was used in the pool those both add quite a bit of CYA. More about different chlorine types here, Pool School - How to Chlorinate Your Pool

 

[onBalance]

It is not algae, black or otherwise.
Another possibility is that when plastering the pool, some foreign material (small leaves, dirt chunks, metal fragments, impurities, etc.) that fell into the pool, and got troweled into the plaster finish, or some impurities were in the plaster mix itself.
It can take a little time to either decay, or to dissolve, or to get oxidized, etc., and become noticeable.
If that is what has occurred, no external treatment will remove the discoloration.

 

[pwomack]

Did you ever figure out the source of the problem? I am dealing with the same thing unfortunately.

 

[JarCar]

I believe I have the same issue as you....ever find a solution? Muriatic acid directly on the spots will help diminish them. Will be trying vitamin C shortly.