Metal stain - Green tint!!!

carlos31820

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LifeTime Supporter
Nov 22, 2010
413
Midland, Georgia
For the past few weeks I have been trying to get rid of some iron metal staining confirmed by the vitamin c test. The ascorbic acid and metal sequestrant (Sparkle Conquest) worked wonders and all the staining was gone. Pool looked great.

The pH, however, remained low for about the past 2 weeks (6.8-7.0 range). Yesterday, I noticed the pool appeared to have a slight green tint to it and some of the staining was returning some of the plastic fittings, skimmer, etc.

I checked the pool levels using the TF-100 kit and all looked fine. My FC chlorine was 3.0 and CC was 0. I wanted to bring the FC up just in case this was something organic. I was out of bleach so I added 2 bags of powder shock to bring it up quickly without having to max out the salt cell.

This morning, the pool, has a stronger green tint to it in the deep end. I'm now thinking that what I have is copper precipitating. I have another bottle of the Sparkle conquest metal sequestrant I could use but I'm concerned that with the ph being so low already, I may cause more harm than good. Normally, when I add metal sequestrant, the pH drops quite a bit. The heat exchanger in my pool heater is copper so I don't want the ph any lower than it currently is.

SOOO, looking at my levels below, how would you attack this? Raise pH, then add sequestrant, or just add sequestrant and raise pH after the fact. How long can I safely run with low pH levels? Does raising ph immediately after adding sequestrant affect the efficiency of the metal sequestrant?

Here are my current levels:

FC 8.5
CC 0.0
ph 7.1
TA 70
CYA 75
Salt 3240
 
I lowered my FC and pH, did the AA treatment. Sparkly Conquest clouded my pool for over 2 weeks. Stains came back. I battled this all summer but finally did another AA treatment, use 16 oz Metal Klear once a week and haven't had a problem since. I just keep my ph around 7.3 and FC to minimum of my CYA....If either get any higher the stains come back because the shock or higher chlorine releases the metals back into the water.
 
So I've been reading that a slight green tint could still be caused by iron staining. I'm not sure how to proceed.

My FC is 8.5 and the sequestrant I use recommends that the FC be close to 1.0 ppm. I was thinking about dumping a pound of ascorbic acid to consume most of the chlorine then add the metal sequestrant. Should I do anything about the pH before or after adding the metal sequestrant?
 
So in deperation, I put 1.2lbs of leftover ascorbic acid and 22oz of liquid Sparkle Conquest metal sequestrant. The pH quickly went lower than 6.8 so I added about a pound of soda ash and it's back to 6.8.

It's been about 2 hours but the green tint and pools stains have lifted. I guess I'll leave it alone for about 24 hours and work on slowly bringing the ph back up to 7.2. It looks like I need to stock up on sequestrant and add some every week or so.
 
Thanks chem geek. I've already ordered some so I can do a weekly maintenance dosage. I also ordered a Culator ultra... not sure if it will work but it can't hurt. My pool water is municipal, not well water.

I suspect my iron is coming from the inside of my stainless steel ladder which is rusting inside. I'm thinking about replacing the ladder. I've found nothing else in the pool that is corroding although I have not checked the LED pool light yet. However, the pool light has bright white trim around it which have never stained so I'm thinking that's unlikely. The pool ladder, however, has bright orange rusty water that comes out when I remove the ladder in winter time and remove the rubber bumpers which touch the wall.

Is it possible to treat the inside of the ladder rails with something to keep them from corroding further? I even thought about trying to fill it with waterproof expanding foam or something like that. I'm just trying to think of a way to keep additional rust/iron from getting in the pool water. Looking through my logs, my pool pH has always been kept in range (between 7.3-7.6). The only times I've gotten the pH lower than this is when I started to take care of the metal stains and the ascorbic acid and sequestrant make the pH drop close to the 6.8 range.
 
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