Need Help With Staining

#1
Hi everyone,

I have been researching online to try and fix some stains in my pool that seem to be from metal stains but I need help troubleshooting a bit more. Here are the steps I have taken so far, along with a few pictures to help illustrate:

1. Suspected stains were from metals so I began the process of doing an Ascorbic Acid treatment (pump ran 24/7 for the entire process, about a week or more)
  • Balanced pool water (chlorine to near 0 and PH to 7.2)
  • Added pool store sequestering agent, two quarts/bottles worth
  • Added 2-3 pounds of pure ascorbic acid powder bought off Amazon. This was added a bit at a time until I could notice the stains getting better.
  • Did NOT add an algaecide, which I regretted....
2. Woke up next morning to find pool extremely cloudy, couldn't see the drain in the deep end. I found out this is normal so I continued to run the pump and brush until everything cleared up.
3. Pool started clearing up after about a 7-14 days or so but I kept getting algae growth, even after several backwashes, so I decided to clean the entire filter grid (found out it was caked in algae). Re-added DE powder when it was all clean.
4. Next day the pool was pretty much perfectly clear. Started to bring chlorine levels up SLOWLY with liquid chlorine only.
5. Eventually got chlorine levels to a normal point and didn't get any stains coming back. I thought I was good to go at this point. Also added a bottle of PolyQuat algaecide from the pool store (60% polyquat) to help prevent any more algae as I brought chlorine up.
6. It is now about a month later, noticed stains slightly coming back so I bought a bottle of HASA Super Stain out, thinking this should be a good sequestering agent, and add the whole bottle. Doesn't seem to make anything better.
7. A few days after adding the HASA Super Stain out the pool is back to looking as bad as it started off as, maybe even worse in spots.

After dealing with all of this, I decided to shell out the money for a legit test kit, K-2006, (which I should have done a looooong time ago) and see what's up with the pool. All levels are coming in at their normal ranges EXCEPT CYA, which is at 150+.

I clearly have been using Trichlor tabs way to long and have stopped using them. The problem now is that my chlorine levels are too low to kill any algae. I was also hesitant to add too much chlorine and cause any suspended metal ions to re-stain (which at this point doesn't matter, the stains are back and in full force).

I am now questioning if these stains could be from algae or if they are in fact metals. They don't get much better by brushing, even with a stainless steel/nylon brush. But they also only got worse after adding the HASA super stain out.

Any help is appreciated. Let me know if you need more info and I'll do my best to get it.

Pool equipment:
~20k gallons
Pentair VS Pump
Hayward 36 DE Filter
City water
Screened lanai enclosure






 
Last edited:

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
#2
Welcome to TFP! :wave: Based on those pics, the staining looks organic to me. You've answered some of your own questions already, and finally getting a good test kit as a HUGE improvement. First thing …. get that CYA down under 80 (at least). Also update your signature with all of your pool and equipment info so we know what you have there (salt or non-salt)? As for "potential" metal, we look at iron or copper. Iron is generally from a well, although some municipalities (or old plumbing) can have elevated iron levels as well. Copper can be a factor if lots of pool store algaecides (non-Poly) were used or an old heater corroded.

But treating for metals (if an issue) is a non-player until you get the CYA down. I would also consider placing a chlorine puck on that stained area for a couple minutes, moving slowly as to not just sit in one spot. Changes would confirm organic staining. Give that some thought and let us know if you have more questions.

For the CYA, if it's still showing really high, make sure to do the diluted test method as noted on the Pool School - CYA page starting at step 8.
 
OP
OP
T
#3
Thanks for the tips. I updated my signature after I posted this I guess, but the original post has been updated with pool specs.

No heaters or any supplies that would be getting copper into the water. Only metal is from the ladder and the pool light. It might be possible that water is draining off our lanai enclosure and maybe metal is coming from that. Been at this house for almost 4 years now and this is the first time the stains have gotten excessively bad. I've been using trichlor pucks the entire time.

I'll try setting a puck on the stain and see what happens, but the stains definitely don't brush off if that matters at all.
 
OP
OP
T
#4
Some good news, I did a quick test with the trichlor puck and it seemed to remove the staining in the test spot, left a near perfect circle.

That at being said, how do I remove all of the stains from the pool? Obviously I need to get CYA down, but will liquid shock/chlorine work to remove the stains or do I need to use granular? If I need granular, won’t I be back to square one with CYA issues?
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
3,695
Northern NJ
#5
You need to lower your CYA to more like 30 to reduce the CL you will need in the . You will likely need to do a good and long with lots of brushing of all surfaces and niches of your pool. The FC needs to be raised to shock levels and consistently maintained above shock level for the duration.

Brushing is critical to break the biofilm on the algae and allow the chlorine to attack it.

Stock up on liquid chlorine, not Clorox bleach.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
3,695
Northern NJ
#7
Alright, so basically get the CYA taken care of and a do a SLAM with frequent brushing until I notice the staining is gone. Am I on the right track?

Thanks for the help.
Yes. . Follow step by step. No shortcuts. Post here with any questions and share your progress. We give moral support during S.
 
OP
OP
T
#9
Hi again all, I'm back with some fairly good news. Went through the entire process of lowering CYA and doing a SLAM. I did a few partial drain and re-fills and got CYA down to around 80-90. I know the SLAM isn't really recommended at that level, but I was working with what I had. Got the chlorine levels to 33+, kept it there for about 5 days, and brushed the **** out of it a couple times a day (steel and steel/nylon bristle brushes). I also did a couple backwashes as the pressure readings went up.

I added some photos below of what the stains look like, and this is what they've been like really for the last couple days, not improving much more from this (the pics do look a bit worse than in person in my opinion). I can live with this until my CYA is even lower. Maybe at that point I'll try another SLAM to see if the remaining staining goes away, or I can try a granular shock to see if they improve.

Any additional suggestions are appreciated.



 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
3,695
Northern NJ
#10
CL levels below “shock “ level for your CYA are safe to swim in. I would keep your FC at levels just below shock level for an extended time. I think over a period of months the FC will eat at the stains. Continued brushing of the stains will help the chlorine be effective.

The lower you get your CYA the less chlorine you will use.