Ok KimKats my first post of the season, I'm stumped

[lefty51]

I'll try to be as brief as I can. 9 days ago we had a party with a lot of swimmers. weather has been hot and sunny. the day after the swim readings were
FC-6
CC-0
PH-7.6
TA-70
CYA-70
CH-150
Borates-40
Salt-3600
Was gone for a few days, then 2 days ago the boss sprayed fertilizer on lawn near pool(she is always very careful around pool), but 6 hours later I mowed the yard( and I always end up with some grass clippings in pool. I mention this as a possibility, but I don't think this is the reason. Anyway, yesterday I go out to check chems and find a very cloudy pool, not green, just very cloudy. and the results were
FC-0
CC-0
PH-7.4
TA-100
CYA-40 possibly 30
I added 484 oz of bleach and 60 oz of stabilizer(all I had left) and tossed in 11 oz of acid to work on TA. Then ran to the store for more bleach.
3 hours later FC was 1, so I added 605 oz of bleach and tossed 3 tabs in the skimmer for CYA and backup. ( I must add that all this time I forgot that I cranked up salt gen to 100% and left it running, so this will skew my todays results).
At 6:00 last night FC was 17, so I called it a day, left pool running with tabs still in skimmer and SWG running at 100%(not on purpose, just forgot about it)
Today is looking better, pool is starting to look a lot clearer and FC was 11.5 and CC-1. added more bleach to Slam level and waiting.
All of this leads to my questions,
1-could this have been a fertilizer problem ( she fertilizes 2 or 3 times a year around pool area and we have never had a problem)
2-could the big loss of CYA be caused by this or if I let the FC level drop to zero would the sunlight and organics eat up the CYA.
3- could this be because I left town and my CYA and FC were getting low anyway and nature took over(kinda what I think happened since SWG was set at 50% and pump was only running 3 hrs in morning and 3 hrs in the afternoon, which is what I run it at normally with no problems.
I caught it in time so we should be okay, but I would like to figure out what happened to avoid this in the future. There you go Kim.
Si

 

[kimkats]

I think you had the "perfect storm" : high bather load, gone for a couple/few days, fertilizer (did it have phosphates in it?), mowing to put said fertilizer into the pool, hot, sunny days. Add that up to the start of an algae party You caught it before it got going good.......poor algae hehe

Your gut is right! You did great! Can boss fertilize after you mow? (I don't know how that works as I don't fertilize).



Kim

 

[lefty51]

Thanks Kim, I said I would let you know if I posted something, just didn't know it would be a mystery. I now think "something" got in the pool, because I have cute 1" to 2" bubbles coming off my aerator that float around for quite a while before dissipating. Not like an algaecide would cause. It almost looks like the grand kids dumped their bottle of bubbles in(need to blame someone ). the weed and feed contains ammonium and urea nitrogen, perhaps there is a surfactant in it as that is what appears to be in the pool. maybe 5 gallons of sunscreen. I'll keep checking, Thanks

 

[funandsun]

What caused the big CYA drop?

 

[lefty51]

I'm not sure, but now I'm questioning my testing . first I let my supply of CYA reagent get low. It should arrive tomorrow. When I tested two days ago it was 40 possibly 30. I added 60 oz of the 66 oz of stabilizer as that was all I had and tossed three pucks in the skimmer for backup FC and CYA.
I lost 9ppm of FC overnight(with pucks removed) with a CC of 1.0, so I tried to test CYA for grins, but didn't have quite enough reagent to fill to mark. That said my CYA is showing 80 to 90?? I would have thought less reagent would make the number lower or is it just the opposite?? I have been consistent in my testing since joining TFP, but I'm rethinking if I am now doing something different. Could the reagent have gotten weaker ?
In the meantime I will just stay with the slam till it's done and the bubbles go away and then retest everything. My overconfidence at being a TFP'er may just have bit me.

 

[Pyrodav]

My friend who has posted here just dealt with this exact same problem. He drained 30% of his water and it helped tremendously. 30% refill here is way cheaper than the chlorine that fertilizer is gonna eat. After two weeks he couldn't get rid of it...so he drained. Nitrates were the problem...lots of them.

 

[JamesW]

Ammonium and urea nitrogen will eat up chlorine fast and will usually create some transient high CC levels.

With no chlorine, certain bacteria can get out of control and begin eating the cyanuric acid converting it into ammonia.