Shocked pool last night and it turned green within the hour

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Apr 23, 2013
11
FC - 0
TC - 0
PH - 7.4
TA - 70
CH - 230
CYA - 50

This weekend the pool was sparkling clear. Last night I checked the Chlorine= low to none and PH=looked to be in the acceptable range. Brushed, vaccumed, and shocked with one pound and within the hour the pool was clear green. Added algeacide this morning and turned on pump. At lunch I went home and the pool was still clear and more of a blue green. Took water sample to the pool store about an hour ago and the results are up top. I was told to shock with two pounds and check in 4 hours, if chlorine was normal or high, then add 8 pounds od alk up/baking soda. I just want to know what the thinking was here. This is only my second year with the pool but I don't ever recall shocking a clear "blue" pool and having it turn green in front of my eyes.

Thanks
 
Re: Shocked pool last night and it turned green within the h

:wave: Welcome to TFP!!!

A clear green after the addition of chlorine typically points to a high metal content in the water.

Before you add any more "shock" {whatever that is} I suggest you read Pool School (button at the upper right of the page). If the powder is dichlor, then you are adding CYA and you are already at the maximum that we recommend. And your TA is fine, so there is no reason to add baking soda.

You have decision to make: continue listening to the pool store OR learn about your pool's chemistry from the forum and take control for yourself (and likely save money in the process). Mixing advice just does not work.
 
Re: Shocked pool last night and it turned green within the h

Thanks. Decision made which is why I signed up here, but I also wanted to let you know what I currently knew which was what I learned from the water test at the pool store. I will be looking into a more detailed test kit that I can do at home.
 
Re: Shocked pool last night and it turned green within the h

Good Choice :goodjob:

Check the link in my signature for the test kits we recommend, note they they are RARELY available locally. And the TF-100 is really the best value and a SpeedStir makes the testing easier and more entertaining.

Really the first steps are to order the kit, and read Pool School, and then post up your first full set of test results.

Here is some info about metals. Others will have to chime in as I have never dealt with it myself:
pool-school/metal%20stains

Ok, well the cal-hypo will be adding CH to the water. With a vinyl pool low CH does not matter, but high can still be a problem. I would suggest sticking with liquid chlorine to try to get some FC registering, but you may need to add some metal sequestrant first.
 
Re: Shocked pool last night and it turned green within the h

This is only my second year with the pool but I don't ever recall shocking a clear "blue" pool and having it turn green in front of my eyes.
Click to expand...
I have observed this phenomenon on opening my pool the past 3 Springs but not before. My pool tests negative for iron as it always has.

Assuming you are experiencing the same thing, just keep everything as you normally would and the pool will turn back to clear blue in another day or so.

I do not understand why some people experience this but I have read it before on this forum and have personal experience.....I just am not convinced as to it's cause.

Tell me about your chlorine history.

Did you have chlorine in the pool prior to this addition or was this the first dose this Spring. How much (ppm) did you dose and what was your CYA level? Are the test results above current?
 
Re: Shocked pool last night and it turned green within the h

After using 1lb of cal-hyp on 4/18, the pool was clear green on 4/19. I thought it was algae because my numbers were good on 4/13 so I got some algaecide and applied it on 4/19. On 4/20 the pool was crystal clear. On 4/22 I did a brush and vac and added 1lb cal-hyp to the pool because the chlorine tested low to none. The pool started turning clear green again within the hour.
 
Re: Shocked pool last night and it turned green within the h

One more thing, does your Algaecide contain copper, many do, and adding it can push you over the tipping point for metals in your water.

Ike
 

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Re: Shocked pool last night and it turned green within the h

Are you testing yourself? I see no reason for the large change in CYA ... guessing this was the inaccurate pool store testing we have come to be quite familiar with.
 
Re: Shocked pool last night and it turned green within the h

I am using Leslies Algae Control which states that it has not metals. While it doesn't look like they test for iron, both of my water tests appear to be 0 for copper.
 
Re: Shocked pool last night and it turned green within the h

Calcium hypochlorite does not have CYA in it. Did you add CYA or dichlor on your own to raise the CYA level?
 
Re: Shocked pool last night and it turned green within the h

I did not. The other two things I have added is Phosfree and initially when the pool was "blue" cloudy, before it turned clear green, I used Ultra Bright. All of these of course were bought at Leslies.
 
Re: Shocked pool last night and it turned green within the h

Well after reading through the pool school I now realize that I am using trichlor as well in the form of the 3" tablets with a floating dispenser. I started using these the same day that I first applied the cal-hypo. In fact the bottom of the dispenser turned brown, which never happened last year. Could this by why the CYA rose as much as it did and why the pool is turning green after each application of the cal-hypo?
 
Re: Shocked pool last night and it turned green within the h

Most floaters will tend to discolor in a brownish tint on the bottom surface where the tablets rest. It has more to do with the aging of the plastic than a problem with your water.
 
Re: Shocked pool last night and it turned green within the h

Iron will oxidize during shock and then in part be filtered over time. Iron is more yellowish but against a blue liner can look aquamarine/green too.

Are you on well water? Did someone fertilize your lawn recently? Both can introduce iron into the water (fertilizer by overspreading.) if it doesn't clear in another day or two of filtering, you may wish to try something like Jacks Magic Pink (for iron) metal sequestrate.
 

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