Help! Staining is back

[dk5jmiller]

I followed the Ascorbic Acid method for removing the staining in my pool, particularly on the steps and the skimmers. Everything cleaned up and was doing great. I was able to keep chlorine around the 3-5ppm target value for my pool and keep pH no higher than 7.2 for about 1.5 weeks. Last week was really hot here (103-109) most days, so had to supplement my SWG (currently at 100%) to keep chlorine at that level. I noticed the staining starting to reappear on Friday and today it's definitely worse. I checked pH and it had creeped back up to 7.4, so I lowered it back down. Chlorine has been as high as 8ppm, but no higher with all the sun. So far, I've added a total of 4 bottles of The Purple Stuff since starting and 4 lbs of Ascorbic Acid.

What am I doing wrong? Do I need to do another treatment? Is there any way I can keep the staining gone permanently? Help!!! It was looking so good and now I'm back to square 1. We are expecting nothing but sun and 90 degree days this week also and I'm concerned about losing control to algae. Any suggestions would be appreciated!

 

[dk5jmiller]

pH is back to 7.1-7.2 and chlorine is 5.5ppm. Staining is still there, but doesn't seem to be getting worse. Should I start another treatment? I've noticed in other posts that maybe I should add more sequestering agent? How much is enough? I've already used 4 qts for 25000 gal. Does this mean I'm locked into using this from now on? I noticed it also seems to affect the chlorine in the pool, which is already a problem because I'm struggling to keep the minimum with the SWG at 100% from the amount of sun and heat we've been having. What I don't get is, the ascorbic acid should be gone now - it's been two weeks since the treatment. However, my chlorine level is hard to maintain. Is that because of the sun/heat or because of the sequestering agent? If the latter, why do I still have staining? Sure would appreciate some advice.

 

[chem geek]

It sounds like you've got quite a lot of metals in the water needing a lot of sequestrant. HEDP does slowly break down from chlorine, but not as fast as inferior metal sequestrants like EDTA. I suspect it's more the heat that is the issue as that does increase chlorine demand -- in my own pool with no sun the chlorine demand goes from 0.3 ppm FC at 80ºF to 0.7 ppm FC at 90ºF. Of course, most chlorine loss is from the sun.

Since you apparently have a lot of metal in your pool, have you considered trying CuLator®? It's unfortunately expensive, but if it's going to work in any pool I'd expect it to work when there are more metals in the water as with your pool. If you have your water tested and they measure metals in the water, then you can track if it is getting reduced and how quickly. If you use it, be sure to tell us your results as we need more reports from users on this yet-too-soon-to-recommend product.

 

[dk5jmiller]

I've got 4 more bottles of Jack's Purple coming. Would you recommend adding in at least two of those right away to boost the levels that should already be in the pool? I was thinking I would then put some more ascorbic acid in a sock around the steps and skimmers, since that's where the staining is. I'm hoping adding more sequestrant would bind up the metal. I guess I thought that once you did the ascorbic acid treatment and added sequestrate - it was a one time deal. Apparently, you need to keep adding the sequestrate on a regular basis to keep the metals bound?

I looked into the CUlator product and it seems to have mixed reviews. The 1ppm product seems to have positive reviews, but the Ultra product (4ppm) doesn't seem too promising. I'm also concerned that the CUlator and sequestrant would cancel each other out.

I know my well has iron issues, as we have to use iron out salt in our softener. When I've been adding water, I've been adding softened water in the hopes that would eliminate some of the iron - plus my CH is at 380 anyway. Are there any products to remove iron from well water before it goes in the pool that are worth anything and affordable? I may just have to live with the staining because it may be too expensive to get rid of it...

 

[chem geek]

The sequestrant is not a one-time deal. More needs to be added though the initial dose is largest and thereafter weekly make-up doses are smaller. That should be on the bottle directions. As for CuLator, it does not conflict with the metal sequestrant and can be used together. And yes, treating for metal stains without physically changing the water free of metals can be expensive though the Jack's product you are using is one of the more economical concentrated HEDP metal sequestrants.