Brown stains appearing on bottom of new pool?

deelowe

Member
Aug 15, 2020
21
Atlanta Georgia
Not sure which forum to post this in.

I'm starting to get these brown spots all over the bottom of my pool. They are more prominent around the perimeter. For reference, the pool was installed in February and is on city water. There are no metal objects in the pool as the deep end has a step out and there aren't any hand rails. The pool is professionally cleaned weekly by the company who did the installation and we've been diligent about not letting leaves or other organics sit in the pool. The stains will sort of come up with a hard scrubbing, but not completely in most cases. At first we just had a few, but they appear to be growing in number. Again, mostly around the perimeter, near where the wall meets the base, but the spa and sun shelf have some on the bottom as well.

I apologize for the quality of the pics. The spots are much more obvious in person. Here's a link to an album with several photos: 12 new photos by dlow

These are my most recent maintenance reports according to the company we're using:

10/05/2020
5 ppm chlorine
8.0 pH
100 ppm alkalinity
240 ppm calcium
3400 ppm salt
1 gal muriatic acid

9/21/2020
5 ppm chlorine
7.6 pH
80 ppm alkalinity
280 ppm calcium
3000 ppm salt
40 % sanitizer output%

9/17/2020
5 ppm chlorine
8.0 pH
70 ppm alkalinity
250 ppm calcium
3000 ppm salt
18 filter psi

09/08/2020

5 ppm chlorine
8.0 pH
80 ppm alkalinity
230 ppm calcium
3600 ppm salt
60 % santizer output%
1 gal muratic acid
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,308
Laughlin, NV
Take some Vitamin C tablets, crush them up in a thin sock, and set on the brown stain. See if it disappears -- if so, it is iron. If not, find out if the pool service is adding any algaecides or other potions.

Your test data does not show a CYA level and it is obvious they do not have a proper test method to measure FC. We would strongly suggest you get your own proper test kit. Relying on a once a week 10 minute visit to manage your pool water chemistry and plaster longevity is not a good idea.
 

deelowe

Member
Aug 15, 2020
21
Atlanta Georgia
Thank you for your help. I'll start learning how to do the pool chemistry myself. We were hesitant to do this initially b/c we didn't want the installer to blame us if there were any warranty claims. That said, we've had a lot of issues with this company's maintenance crew, so maybe it's time to start doing it ourselves.

Based on the evidence thus far, if it is iron, where could it come from? We're on city water.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,308
Laughlin, NV
City water can have iron. It is not an EPA registered contanimant so your local water authority does not have to report it. It can build up. Also, do you have any lawn or bushes near by that could have been fertilized recently? Most fertilizers have iron in them.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,308
Laughlin, NV
Also - call the pool builder. Since you felt you needed to use a maintanance company to satisfy the builder, then put it on them why you are getting staining.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,308
Laughlin, NV
Its possible. Solid product make more sense but enough liquid product may cause it too.

High pH and elevated FC can exacerbate iron staining.
 

JamesW

TFP Expert
Mar 2, 2011
21,093
Looks like iron from particles. Try the vitamin C.

What products are being broadcast near the pool?
 

JamesW

TFP Expert
Mar 2, 2011
21,093
Possibly getting in pool.

Maybe they blow off the deck with a leaf blower after broadcasting the fertilizer?

Are the granules on the driveway causing stains?