Effect of HTH Metal Control on Pool Chemistry

[GregoryRG]

I did a few searches of the forum regarding the potential effect of HTH Metal Control on pool chemistry and didn't really find anything.

I'll be needing to add some water to pool later this week (evaporation, kids splashing, and soon a backwash), and I'll be using well water that is from a source that is tapped off my main water line prior to the water softener system for the house. When I did my initial set-up and fill, I used about 750 gallons of well water then had a pool water co. fill it the rest of the way. When I did my initial chlorine addition, I got tea-brown water in the filter and some minor staining. That went away with some light brushing. My theory is that the chlorine and the iron from my initial 750 gal fill reacted. I haven't used a metal control product yet as I haven't seen the need to (no more staining, etc.), but don't want to risk it with my topping-off. I looked at the metaltrap filter and it seems pricey and not big enough to do an adequate job at any decent flow-rate. So, I picked up a bottle of HTH metal control after seeing it had the same active ingredients as Magic Jack. But, my question is this:

What is the potential impact to my pool's chemistry (change in pH, TA, CH, etc.), if any? Here are my test results from this PM:

FC: 7.5
CC: 0.5 or less
TA: 70
CH: 125
CYA: 60 (still working itself into the water)
Borates: Not Tested Yet - test strips on the way
Iron: Not Tested Yet - kit on the way.

Note: I'm letting the FC drift down from shock levels earlier in the week as I got my CYA in the pool and started to get it distributed into the water. I'll kick on the SWG tomorrow evening, as the FC has dropped about 2.5 to 3 ppm per day the last two, as the CYA kicked in (sunny, 89F on Sunday, 93F today, high 80's tomorrow).

Or should I try the Metaltrap Liquid?

Thanks,

Bob

 

[chem geek]

HTH Metal Control based on this MSDS is 20-30% Etidronic Acid which is a synonym for HEDP. It will not affect your water chemistry in any substantial way. Chlorine will slowly break down HEDP (especially in pools exposed to sunlight) so you will need to add a maintenance dose weekly.

Is the Metaltrap Liquid you refer to this Liquid Metaltrap? If so, then that is not an HEDP metal sequestrant.

You are right that chlorine reacts with soluble ferrous iron in the well water, oxidizes it to ferric iron, and this then forms iron oxides that are insoluble. These can then either stain or precipitate and get caught in the filter. You are fortunate that you do not have a plaster pool since it is more likely to stain. If you were to raise the pH, more iron would precipitate and hopefully get caught into the filter (for plaster pools you wouldn't normally do that since it could cause more staining of plaster).

You can either maintain HEDP metal sequestrant to keep the metal in solution or you can try to remove more of it in the filter using a product such as Metal Magic or remove it in the skimmer using a product called CuLator (if you use this and run into any problems, contact the manufacturer since sometimes special instructions are needed).

 

[GregoryRG]

Thanks!

 

[Snap96]

I'm 2 weeks into using CuLator and from my experience it's a complete sham. I'll give it 2 more weeks, as suggested by the product instructions, but I highly doubt it actually does anything. My daughter's hair still turns green and the CuLator packet is suppose to turn blue if it's capturing copper and it shows zero signs of any sort of blue tint.

I've used Bioguard Pool Magnet Plus, Jack's Purple Stuff, Natural Chemistry Metal Free, and HTH Metal Control with varying degrees of success. These items did not impact my water chemistry.

 

[chem geek]

Call the CuLator company (954-764-7654) to get help since sometimes they use different procedures than the regular instructions (for example, when removing iron they sometimes add an algaecide to kill iron bacteria). It may be that you have so much copper that it will take more than 2 weeks. As for the packet turning color, it's not always visible from the outside. Again, talk to them about it.