Help - I'm watching my pool turn green by the minute!!

[dblais]

I came home today and tested my water. Pool was clear. But I've been having trouble keeping the chlorine levels up, and found my chlorine levels near zero, even though I put (2) 128 oz. 10% bottles and (4) 3" trichlor tabs in the strainer just yesterday.

So I added three more bottles of 128 oz./10%, and also a box of Borax as I've had to add stabilizer to get my CyA up a bit, which pushed my pH down.

Suddenly I look out, and am now watching the water turn green by the minute!! Is it possible an algae bloom was on the verge with the chlorine levels near zero, and what I've just added in the last 90 minutes will take time to kill this bloom? Or could it be a chemical reaction of something else?? It's getting darker and darker as I type.

My readings right now are:

FCL- 10
TCI - 10
Alk - 120
CyA - 50
pH - 7.6
TH - 400

 

[JasonLion]

Welcome to TFP!

Are you seeing a cloudy/murky green or a clear transparent green? Cloudy/murky green is algae, while a clear transparent green would be metals in the water interacting with the chlorine.

 

[dblais]

Clear transparent green. Funny you say that. I was wondering why the water itself looked somewhat clear (I can see the traps clearly in the deep end). But why would this happen? I've never seen this before after adding chlorine. One other thing I forgot to mention, is I had some shock tablets left over in a bucket last year from what is sold as a "Sustain" system. So I dropped the small balance that I had left in the skimmer. Could it be because of such a heavy dose of chlorination?

Thanks for your response. It startled me to see it happen. I could literally see the green area swirl and grow across the pool.

 

[Bama Rambler]

Clear green is usually caused by copper in the water. Have you added any copper based algaecides?
What all have you put in the pool?

 

[dblais]

Uh . . . guilty. Yesterday I put HTH Super Algae Guard. But reading the ingredients, I didn't see anything about copper, unless it's hidden in the scientific wording that starts with "Alkyl".

I went and purchased some sequesterant, and am running the filter overnight. Looks like it's sloooowwwly clearing.

I've begun reading the system here, but could anyone possibly answer a for me? If using the liquid chlorine process, does that act as both the shock and maintenance chlorine? I'm used to using this "Sustain" system from the pool guys, but it's expensive, so I'd like to learn a more wallet friendly way. That system has a weekly measured does of shock, as well as 3" chlorine tabs to carry through the week. I'm fuzzy about whether both are needed, or is it unnecessary if the chlorine level is maintained with regular doses.

Thanks so much for your help!

 

[MikeInNH]

"Shock" is a process not really a chemical. When your pool is balanced you maintain a specific ppm of chlorine per your CYA level to keep the water clean. Shocking (bringing the chlorine level up to shock level) is needed when your pool has organics growing. Either you see it, you measure it in CC being over .5 or notice it takes extra chlorine to maintain the chlorine ppm you want. No need for any expensive chemicals. The pool school link rocks, so much info in there. I've been using the BBB method for a few years and still look through the pool school now and then. My brain only remembers so much.

 

[dblais]

Awesome Mike - thank you so much for your answer. I've had a problem with chlorine quickly dissipating this year, and can't seem to keep any free chlorine. Glad to hear you've been using this system. I guess I'm off to school!