Brown spots On new plaster


New member
Sep 3, 2020
Frisco, TX
My pool is less than 2 months old and I am seeing about 25-30 small brown spots dime to quarter in size mostly on the floor of the pool and a couple on the walls. The pool was plastered on 7/18/2020, and acid washed the next morning before they started filling the pool with an Orenda Startup Barrel with Calcium and SC1000. Filling the pool took 2 days. It was about a week after the pool was filled when I started to notice the brown spots appearing. The pool has a White Pebble Sheen finish so when the water is calm you can see easily see anything.
I have been doing my own maintenance on the pool and testing the water daily using multiple test methods just for comparison, I used the Taylor test strips and Taylor Test Kit K-1005, and we also take a sample to Leslie's 1-2 times a week for testing too. I log all my reads and plug them into the Orenda Dosing Calculator to determine what chemicals I need. I have been able to keep the water crystal clear and the cemicals are never to far off. Which has kepy my LSI where it needs to be. On top of the normal pool chemicals I am also using Orenda CV700 and SC1000 for weekly maintenance. I also did a purge with SC1000 thinking the brown spots might be rust stains but it made no difference in the stains. And on 8/3/2020 I removed and cleaned all the filter cartridges. We brushed our pool daily for the first 28 days before installing the pool cleaner. I just don't get why these stains keep appearing. We did not get our sod installed in the back until 8/19/2020. Which is another reason we were brushing so often because on windy dry days or rainy days we would get a small amount or dirt in the pool. I have also tried rubbing the spots with Vitamin C tabs as well and that did nothing to help the spots. So we finally decided to try some Muriatic acid on the spots this past weekend. We used a medicine syringe the type with the round head that fits on the liquid medicine bottles. I think it holds 5 or 10ml of acid. We would swim down and place the syringe right over the spot and inject very little acid which stayed contained right over the spot for a few seconds before using a pool brush and it easily removed the spots. So we did this to all the spots in the pool. And it was looking great again. Well the past couple days it has been raining a ton here. So I went out this morning to check the chemicals and noticed about 5 of the spots reappeared. I had to add some chlorine, acid and baking soda to get the pool balanced from all the rain so could the rain have thrown my chemicals off for 2 days and allowed the spots to come back. Most of my neighbors don't touch their pools and the ones with pool services only have them looked at once a week. So I feel like I am more on top of my pool and I feel like I am doing everything right with maintenance and chemicals so why is this happening I just don't get what I am doing wrong. If anything I am spending way to much time caring for this pool.
I was reading through these posts and saw Jimmie48 had similar problems on his pool which is not much older than mine and we are in the same city. I wonder if we have the same builder that is doing something wrong? I have made my pool builder aware of the spots but they haven't done anything yet. Thanks for listening!


Gold Supporter
TFP Guide
Nov 12, 2017
Central California
Others here may know and share what those spots might be. My share: if you think you're having trouble getting the PB to come out and deal with this now, imagine what will happen if he finds out you've been squirting acid on the finish. Regardless if that is actually causing any issue or not, you could be giving him a legitimate reason to void your warranty. And this should be a warranty issue. Deal with him first and/or the manufacturer of the finish, before you go applying DIY remedies.

Though there's certainly nothing wrong with asking about it here, and gaining some ammo for dealing with the warranty holder. Just don't act on the knowledge yourself, yet.


Mod Squad
LifeTime Supporter
Jan 17, 2012
Evans, Georgia
Did you add any Abalone shells to your finish? We've had folks tell us they had problems with them discoloring and turning brown.

Are you adding any product to the pool that you're tossing in, like a granular product? How about fertilizers being spread around the pool?

Got any pics you can share?

As an IMPORTANT side note- you *seriously* need your own reliable test kit. The K-1000 doesn't cut it, and pool store results are only worth the price you paid for the test. They're more often inaccurate than not.
For a large pool liike you have I would recommend the TF-100--->

You're not using Clorox XtraBlue pucks I hope???

We need to see test results:
Salt if applicable



Well-known member
Dec 13, 2019
Frisco, TX
Hey Mark,

SO I am pretty certain in my case it was caused by the starter fertilizer my landcaper used as I have not seen them reappear since. I certainly didnt see that many spots it was kind of a sporadic rusty looking spot kind of intertwined with the pebbles, and one was very surface where I could actually scrape it with my fingernail. If you are seeing that many spots I would tell the PB to come look at it asap. You have a finish warranty, and even tho you tried a little acid on a couple of them I wouldnt even fret over that. I have a feeling the guys are right...its probably some metals in the shells/rocks as the muratic would eat the rust away but if they continue to rust it will come back. I completely agree get yourself a decent test kit(I have the TF100) and get us some tests so the experts on this forum can help you out. Hang in there and feel free to pm me if you have any questions on my case...