Big thunderstorm turned water green

[Razorhog]

I've read all over these forums about this and still can't come to a conclusion. My water has been sparkling clear for weeks, and I've never let the FC level drop below 6 ppm, and CC has always been 0. CYA is steady at 50 (prior to rain, will test again tomorrow) Last night FC was at 8, and I added enough cal-hypo to bring it to 11. After the huge thunderstorm, this morning the pool was about 1/2 inch from overflowing, and the water was cloudy and light green. FC tested at 8, CC is 0. I added cal hypo to bring it to shock level of 16 at 12 pm. At 7:30 pm, FC was 11. Added enough cal hypo to raise FC to 19 and will test again in a couple hours to see if it is dropping. I put the filter on waste to lower the water level and vacuumed out a lot of detritus. The polaris got a ton of leaves off the bottom.

At any rate, there seems to be a connection between thunderstorms with heavy rain and pool water turning light green and cloudy. Maybe the addition of all of the organics from rain and water running into the pool just overwhelms the chlorine...however, wouldn't the FC be depleted if there was enough algae in the water to make it green?

 

[duraleigh]

If water is running into your pool, all bets are off.

There are no organics in rainwater....just water and an ultra-tiny microscopic speck of airborne dust in each drop.

 

[Razorhog]

If water is running into your pool, all bets are off.

There are no organics in rainwater....just water and an ultra-tiny microscopic speck of airborne dust in each drop.

Well, I just assumed that some water was running of the concrete around it, but it is really set up well so that it shouldn't. It's just hard to believe that we got enough rain to raise the water level in a pool that big by 6 inches or so. I would have gone out and observed during the storm, but it was producing some wicked lightning. I live on top of Crowley's ridge, with a lot of tall trees around the pool. Plus I'm a little skeered of lightning

 

[woodyp]

If you got 6 inches of new water into the pool, that dropped your FC level right there------especially if you were at a minimum prior to that.

 

[lkalred]

I noticed the same thing after one of our spring thunderstorms. Asked about it in "green tint after thunderstorm". It did clear up pretty quick. The water lost the green tint in less than 24 hrs., was cloudy for about 24 hrs., and then went back to clear without me doing anything. Seems that "nitrogen fixation" that lightning brings about during storms was the most likely culprit. If it makes you feel better, go ahead and shock, or SLAM the pool. Whatever may have responded to the increase in nitrogen doesn't need to be in your pool anyway. Be sure to be mindful of the dilution of your pool water and how that will change your chem levels.