Shocking pool causes CLEAR GREEN TINTED WATER

[LisaM]

Had a pool with lots of algae. Shocked the pool, cleared up the algae. Now I have clear green tinted water. It appears to actually be green/yellow on the liner possible. Water when put into a glass is crystal clear. From my research this appears to be Iron. I did use creek water to top off and since my well water has a lot of Iron in it I am guessing that the creek probably does too.

Now what??? How do I get this green tint out? Hopefully quickly too. Am having a pool opening party this weekend.

 

[JasonLion]

Yes, iron in the water. The green will probably go away as the FC level comes back down to normal. You can get rid of it more quickly by adding a startup dose of sequestrant.

 

[Lblamboy]

Jason's the expert here, and his advice parallels what I've seen elsewhere...

However, since you also said you're fighting a massive algae problem, it might be something different too, so I'll chime in with my 2 cents (I dealt with the same challenge recently)....I saw a site a few weeks ago (when I was dealing with the same issue) that had a different explanation than the normal "metals in the water" answer...I can't find the link now (of course!), but they showed pictures of a pool with brand new fill water that had a residual green tint like you describe, and they attributed the tint to the existence of tap water chloramines (and tri-chloramines, in particular, IIRC). They said they see it a lot when filling new pools, since many municipalities apparently have high chloramine content in their tap water, and the chloramines apparently have a naturally light green tint to them?!? They said shocking away the CC would remedy the problem...and they talked about this in terms of the pool's initial chlorine demand on startup (if that helps with your Google searching!).

Their explanation (coupled with pictures that looked eerily similar to what I was seeing) seemed logical to me, and since it sort of mirrored my algae situation (I didn't have new fill water, but I'd definitely been shocking the heck out of the pool, but was still struggling to really stay ahead of the curve and get rid of my CCs), and because I didn't have any reason to suspect metals when I'd never had any before, I tried their approach and had great success.

Jason's suggestion is to wait for FCs to drop and see if the green goes away, which might happen either because 1) your FC/Metal interactions drop below visible levels of greenness, or 2) it might be because your CCs have gradually oxidized away and lost their natural tinting impact on the water...The only downside to this approach of Jason's is that if your water is green either b/c you 1) still have some algae, or 2) because your CC's are really high...In the first case, waiting could either let the algae come back, and in the second, you might be waiting a long time to get to a point where the CC's oxidize within a reasonable time...So I'd bias towards continuing to shock, lest all your previous shocking and brushing work be in vain...The downside to that approach is that it obviously costs money for the shock, and, if you do have metals, it might make the problem worse!

Good luck!

 

[JasonLion]

water is green either b/c you 1) still have some algae

There can't be live algae if they have been shocking and the water has cleared up all the way to transparent.

 

[sbluhm]

I had one other thought, sometimes powdered shock contains copper, if you used powdered shock when you were cleaning up the algae. Either way, sequestrant should help.

So how did the pool party go? What did the guests say about swimming in the green water?

 

[Lblamboy]

water is green either b/c you 1) still have some algae

There can't be live algae if they have been shocking and the water has cleared up all the way to transparent.

Really? This happens to me at least once a season...I get a bloom, think I've knocked it out with a decent dose of superchlorination/shock and/or a'cide, and brushed the heck out of the pool to the point of having sparkling blue water back, and then pat myself on the back only to see that greenish-yellow, cloudy tint come back to the water a few sunny days later...usually b/c I got lazy and didn't really keep FC elevated long enough to really knock it all the way out (which is, admittedly, a little tougher to do with a SWG...or at least that's what I always tell myself!)...and,, unfortunately, if you don't get it ALL, it grows back really quickly in the heat of summer. However, if you really jump on it when it first starts to make the water hazy again, it's a LOT easier than waiting for it to bloom elsewhere again.

My experience with algae (and I probably have way *too* much) is that it's sorta like what my Dad (pharmacist) says about taking antibiotics -- Too often, folks just take the pills until they start to feel better, but there's a reason they give you ten days worth when it only takes 4-5 to feel better...Funny thing is that I intellectually understand that about Rxs, but get lazy when it comes to pool scrubbing after a bloom!

Anyway, the main point of my post was to suggest that it might be the CC that is causing the green tint...I've searched my history to find that link I mentioned, but can't seem to locate it...might be on my Ipad though!

 

[JasonLion]

Alright, yes mustard algae can still be hiding somewhere, and in more unusual situations ordinary algae could still be alive in a biofilm, but there can't be enough in the bulk pool water to tint the water green.