Metal Stains, Sequestrant, Phosphates, Cheap Test Kit & AA

[Chuck_Davis]

I got this information today from Jack's Magic and LaMotte and thought I'd pass it along.

Jack's Blue Stuff is better than their Pink Stuff if you have copper stains. (I have both copper and iron stains, from a still-unknown source.)

Jack's Blue Stuff is an organophosphate metal sequestrant, which is not a nutrient for algae. The Blue Stuff can break down into an orthophosphate, which is a nutrient and can cause algae blooms (unless chlorine levels are kept high enough).

Some phosphate test kits test for both organophosphate and orthophosphate, and if you are using an organophosphate metal sequestrant this can yield crazy-high readings that don't drop even with a phosphate treatment.

The LaMotte phosphate test kit only tests for orthophosphates.

Doing a phosphate treatment will not degrade the organophosphate metal sequestrant in Jack's Blue Stuff. The phosphate treatment will remove the orthophosphates.

LaMotte has a test kit for metal sequestrant levels that is less than half the cost of the test kit sold by Jack's. (Part no. 4064-01, around $40 online.) Jack's recommends that the sequestrant level be tested weekly and raised to 12 ppm if necessary. I would expect that the savings from using the test kit vs. Jack's standard recommendation of 6-8 oz./10,000 gallons/week would pay for the test kit.

You can get a kilogram (2.2 pounds) of pure ascorbic acid from multiple vendors on eBay for around $18 with free shipping. TFP recommends half to one pound of ascorbic acid per 10,000 gallons.

I tried the CuLator (http://www.CuLator.com) product this summer to try and physically remove the metals from the water (rather than just keep them suspended with the sequestrant), but I don't think I was using enough or the right kind of sequestrant to carry the metals to the CuLator. I'm going to install a new CuLator as part of my upcoming AA treatment+shift to Jacks' Blue Stuff and see what happens.

CuLator recommends the following sequence of events: Install new CuLator, perform AA treatment, add sequestrant.

The CuLator Ultra Powerpak 4.0 has 4x the product for around 2x the price of the 1.0 Powerpak. The Ultra Powerpak also comes with a plastic "egg" that allows the CuLator to be placed in the lint basket to maximize the water flow over the CuLator. I've only been able to find the Ultra Powerpak online.

I'll probably put the used CuLator "egg" in a skimmer to get as much use as possible out of it.

(Weird side note. Just by chance I've done my AA treatments in the later afternoon, and the stains have not fully been lifted. The next morning, as soon as full sunlight hits the pool, the stains disappear within a half hour. This is true for surfaces in both sun and shade, so it appears that something in the sunlight "activates" something about the ascorbic acid in the water.)

 

[chem geek]

Re: Metal Stains, Sequestrant, Phosphates, Cheap Test Kit &

Thanks for the info. Some we knew, and some we didn't. We knew that the better metal sequestrants were organophosphates such as HEDP as they tend to break down more slowly from chlorine. By the way, the Taylor K-1106 also tests for orthophosphate. As noted in this Taylor literature direct phosphate tests only test for orthophosphate. To test for organic phosphates, one needs to oxidize them first to release the phosphate. This paper talks about some standard methods for phosphate detection. The Taylor kit I referred to uses the stannous chloride method.

That is interesting info about the ascorbic acid treatment. We hadn't heard that before. Normally, ascorbic acid should reduce the metal stain and not need sunlight so we'll have to track other people using the AA method to see what happens.

 

[Jeetyet]

Re: Metal Stains, Sequestrant, Phosphates, Cheap Test Kit &

Were you bringing FC down to 0 before adding the AA? Asking because I'm wondering if maybe there was some FC still left in the water overnight that the sunlight was burning off allowing the AA to do its job more effectively.

 

[Chuck_Davis]

Re: Metal Stains, Sequestrant, Phosphates, Cheap Test Kit &

My (LaMotte ColorQ) test kit read zero FC. I also didn't connect the (alleged) mental dots on the sunlight effect until after this last AA treatment, so when the stains didn't fully disappear I put in all 2.2 pounds of AA in a 15,000 gallon pool. This should have overwhelmed any residual FC. (Learned my lesson, though. It took a *lot* of chlorine to burn off the AA until I could get FC to come back up.)

It's quite possible, of course, that I'm using the sunlight effect to explain some other process or coincidence.

 

[Chuck_Davis]

Re: Metal Stains, Sequestrant, Phosphates, Cheap Test Kit &

One more tip from the trenches. A sock filled with a handful of (cheap, 1000 mg.) Vitamin C tablets can be used to spot-treat stains. I've also tied the sock in front of a return to hit the stains from where the outflow hits the wall or steps.