Copper or Algae or Both? Green water after shocking pool and

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G

gbekurs

0
Apr 30, 2013
4
Lafayette, LA
Hello! After reading pool school and lots of the other advice on here, I realize we've been going at all of this the wrong way. We're new to this and just aren't sure how to get to the point to where we're totally on the TFP method. Any help is appreciated - here's a quick history:

(current water test info as at the bottom)

Bought the house (with pool) last Spring. The water was clear and we maintained it easily through the summer using tri-chlor tablets and di-chlor shocking weekly. We kept the pool open through the winter and kept it chlorinated with tablets. Throughout this time, the water was clear.

3 weeks ago, on the advice of a pool store, did an ascorbic acid treatment, with the hope of removing some stains. This clouded the water, of course. We let the chlorine fall to 0 as instructed, and used algaecide (HTH brand) in hopes of preventing algae. The water hasn't fully cleared since then.

2 weeks ago, after acid had supposedly had time to work, added aqua chem clarifier to help remove contaminants per pool store's direction.

Also added some of their pink colored scale remover - enough to treat the pool per their instructions. Not 100% sure why they told us to add this.

1.5 weeks ago, shocked pool with di-chlor (up to 28 because CYA was reading 70, according to pool store). The pool instantly turned very dark green. After 24 hours, I added HTH metal out. After another 24 hours, the green was gone but the water was still very cloudy.

I repeated this process twice more over the next week with the same results.

2 days ago, I shocked again, but used bleach this time (up to 28 with CYA 70). Same thing happened -- the water turned green again. I went to the pool store and they sold me some of their metal out, which i used. This did remove the green again. They also sold me some cellulose to put in the skimmer to help the filter remove particles. The water did get slightly clearer.

I shocked again with bleach last night (same amount - up to 28 because CYA is reading 70). My water is now green and cloudy again and I don't feel like I'm making progress.

It seems to me that, because the green comes AFTER I shock, this must be metal in the water, but that wouldn't explain the cloudiness would it?

Also, the water only holds the chlorine for about 6 hours every time I shock it. Then my FC is down to zero. This last time, it dropped from 28 to 2 overnight, but i guess that's better than 0.

I would appreciate any help - we're ready to swim, but green and cloudy aren't attractive and I don't know whether I have a metal problem or an algae problem (or both).

My latest test results are:

FC - 2
TAC - 4
CH - 270
CYA - 70
pH - 7.2
Alkalinity - 120
(These are from the pool store -- i have ordered a test kit, but it won't get here until next week). The store also SAYS there's no iron or copper in the water, but then add a disclaimer that their tests don't always pick it up.)
 
Re: Copper or Algae or Both? Green water after shocking pool

Welcome to TFP!

Yes, both metals in the water and algae. Green right after you add chlorine is from metals in the water and an insufficient sequestrant level. You need to add sequestrant regularly to maintain an appropriate level, otherwise the metal stains will return.

The constantly losing chlorine and cloudiness mean there is something growing in the water, almost certainly algae. You need to properly shock the pool, which you have not yet done. Because your CYA level is so high that means using massive amounts of chlorine. See the instructions on how to shock in Pool School.
 
Re: Copper or Algae or Both? Green water after shocking pool

My guess is that you have both. If you had metal stains and the AA removed them, those ions are somewhere. And there's a good chance there was some copper in the algaecide.

With CYA = 70, your minimum FC level should be 5, and when you dose, aim for 8 until you get your test kit. Then run an overnight chlorine loss test. If that doesn;t pass, you'll need the shock process. That will clear the cloudiness, and if it's still greenish, you may need to add a metal sequestrant. A sequestrant doesn't remove the metal, it just binds with it so it stays dissolved in the water. It needs to be renewed periodically.
 
Re: Copper or Algae or Both? Green water after shocking pool

Thanks to you both. I will shock following the pool school directions -- I didn't realize I had to KEEP it at shock level for that long (pool store just said dump it in) :). Do you recommend a specific sequestrant, or are they all pretty much the same? Thanks!
 
Re: Copper or Algae or Both? Green water after shocking pool

The quality of sequestrants varies dramatically. We recommend sequestrants based on HEDP, phosphonic acid, or phosphonic acid derivatives. ProTeam's Metal Magic and Jack's Magic The Pink Stuff (regular), The Blue Stuff (fresh plaster), and The Purple Stuff (salt) are some of the top sequestrants. You can also find many other brands with similar active ingredients, some of which are noticeably less expensive.
 
Re: Copper or Algae or Both? Green water after shocking pool

Thank you all! I now have the clearest water I've ever had. I also think I've probably already saved the amount the test kit cost me on chemicals alone -- I'm sure the pool store would've gotten at least that much out of me, but I solved the problem with bleach (alot of it, but it's cheap) and a bottle of Jack's. I really appreciate the help!
 
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