green tint after thunderstorm

[lkalred]

This is the second time this has happened. We have a pretty strong thunderstorm and the water immediately takes on a green tint as well as becoming very cloudy. Last time I was able to shock the pool right away. This time we have guests and I let my 11 yr old convince me not to close the pool and shock it.
Question is: is this the wrong call? Am I now in for a protracted fight to get the water back to clear and sparkling?
Do I have to jump on the pool immediately after an event like this or is there some leeway to play with?

Thanks. I love being able to pose these questions and get advice from experienced pool caretakers and not having to be completely on my own.

Keith

 

[Smykowski]

Can you post a full set of test results?

Rain should never be a problem in a properly maintained pool, unless you have an IG pool where the ground is sloped the wrong way and your backyard is draining into your pool. As a percentage, usually the amount of water going in just isn't high enough. I fill my pool with rainwater from the roof.

 

[duraleigh]

+1 what smykowski just posted.

Unless you have runoff going INTO your pool, rain should be a non event. The four+ inches we had here a couple of days ago did not change my test results one bit.

Posting current test results will help us determine if there is something else going on in your pool.

 

[JohnN]

I'm just speculating here (we really need a full set of test results). Your FC is on the low range for your CYA. During normal conditions, you are killing off algae just as it grows. However, during rain, your chlorine can't handle the added organics. Do any of the experts think this sounds like a possibility?

 

[lkalred]

Thanks for the replies.

test results: 5/24 (prior to storm) 5/25

FC-12.5 FC-7
CC-<1 CC-1
TA-80 ph 7.4
CH-500(last test done on 5/17 TA-80
CH-420
CYA-50

5/24 was allowing FC to drift down post shocking.
5/25 1300-Pool appears cleaner but still very cloudy, green tint is gone, should I assume that FC came down so quickly because it was killing algae? and that cloudiness will be filtered out in time?
Also, can the drop in CH be attributed to dilution? (Hoping)
Maintaining CSI around +1-2

 

[lkalred]

My formatting was altered upon submitting reply. Hopefully, it is still decipherable.
Also, is it possible that the tree over part of the pool is causing this cloudiness/algae look after rainstorm?

This is great. Having other people helping me with my pool concerns. Will make my learning curve a little easier to handle. Maybe one day I can actually answer someone else's question. Thanks!!!


Keith

 

[duraleigh]

The tree is not relevant. You had organics in your pool that caused your FC loss. Unless the CC's test goes back below 1 ppm in the next day or so, you need to return to shock value chlorine levels and start over until you meet these criteria...
1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.

 

[rsmitch]

Many people notice pool colour changes after electrical storms. With electircal storms there is nitrogen fixation which occurs and hence natural fertilization of our gardens fields and lawns (why eveything looks greener after a thunderstorm) and so it makes sense that the added nitrogen load to the pool would envigorate algae and other criters who enjoy nitrogen meals..hence the colour change, cheers Roger

 

[JohnT]

Many people notice pool colour changes after electrical storms. With electircal storms there is nitrogen fixation which occurs and hence natural fertilization of our gardens fields and lawns (why eveything looks greener after a thunderstorm) and so it makes sense that the added nitrogen load to the pool would envigorate algae and other criters who enjoy nitrogen meals..hence the colour change, cheers Roger

Everything looks greener after a thunderstorm because the light is not polarized. The amount of NO₂ generated by a single storm is small, and will have no effect whatsoever on a pool.

 

[lkalred]

Thanks everyone!

Water has returned to clear, was cloudy for awhile but that has cleared up too.

FC-8 (steady)
CC-<1
ph-7.4
TA-80
CH-450
CYA-40

Last time I checked CYA was 50. I will assume that rainwater dilution was the cause of this lowering, though the amount I drained to bring the level back to normal was very small.

 

[rsmitch]

Many people notice pool colour changes after electrical storms. With electircal storms there is nitrogen fixation which occurs and hence natural fertilization of our gardens fields and lawns (why eveything looks greener after a thunderstorm) and so it makes sense that the added nitrogen load to the pool would envigorate algae and other criters who enjoy nitrogen meals..hence the colour change, cheers Roger

Before you pan the nitrogen addition to your pool from electrical stroms, many people do notice pool colour changes after storms and studies have shown nitrogen levels of up to 4 kgs of nitrogen deposited per hecatere after electrical storms not to mention the addition of nitrogen byproducts from industry brought down by heavy rains. So Nitrogen fixation is a source of additional bioavailable soluble nitrogen. I agree the dose is small but possibly worth considering as a contributing agent?
That aside possibly the colour changes can be attributed to other airborne agents made soluble by electrical discharges..just a thought. Given so far the colour changes induced by electrical storms is speculation, please provide some alernative hypotheses..thanks Roger

 

[duraleigh]

We are starting to hijack the thread just a bit but let's go back to OP's post wherein the thunderstorm caused the pool to change color and get cloudy.

I have had my pool for nine years now and have never noticed a thunderstorm changing the pool color nor clouding it up in the slightest bit. I think we should determine just how often that happens.

So do we have any other members that have experienced this?

You can't count an algae bloom as changing colors because if a t-storm and an algae bloom accur one after the other, that algae has been in your pool for a pretty good while.

In other words, the t-storm didn't cause the algae, it was inadequate chlorine that allowed algae to develop and the t-storm simply put it "over the edge" allowing it to show up visibly.

 

[harleysilo]

Okay since we are talking theories, my wife says she can tell it's getting ready to rain cause the trees leaves "stand up", i always say it's the wind.......she thinks it's like a physical change in leaf orientation, like how plants turn toward the sun....I thinks she's crazy, but those leaves sure do look like they are standing up!

To the OP: Your 11 year old can swim up to "shock Level" for your CYA, so no need to disappoint in the future. Just keep that FC consistent and the next big storm will be no problem!

 

[duraleigh]

We are really still hijacking the thread by getting off OP's questions so I'm gonna ask that we drop the t-storm questions and I'll start a different thread on that.

Harleysilo is correct, though, it is safe to swim in anything up to shock level so OP can still swim next time.