SLAM - FC Drops Fast - No CC

omayhemo

Active member
Jun 4, 2020
28
Texas
I have what appears to be some brown spots. They're not coming up with VitC, I tried that because I recently had an application of fertilizer. I do not generally lose more than 1ppm overnight and never have more than .5 CC.
I decided to SLAM anyway to be sure. I brought it up to 20 FC (50 CYA). Within 3 hrs, FC was down to 12.5, .5 CC. I brought it back up to 20 FC, another 5 hours it's already down to 12 again, 0 CC.

Is it normal to have THAT much FC consumed that quickly and not have any CC?

The spots are not fading.
 

omayhemo

Active member
Jun 4, 2020
28
Texas
SLAM Continues. This record is probably more for therapeutic purposes than for any readers, so be it. :unsure:

Twas a cloudy and raining day. Stone and wood work continued near the pool, a hard rain washed large amounts of debris and dirt in; I skimmed and brushed. I brushed and brushed and brushed some more. Vac'd once. Changing the skimmer socks, I found them gray from stone dust and full of lawn materials from the mow. I've used far less LC to maintain 20ppm today as compared to yesterday's several gallons. Despite the low UV that's gotta be progress. The pool lost 3ppm to mid-day, I dosed; another 5ppm to evening, I dosed. The UV index was very low today and a lot of water was washed into the pool due to rain and incomplete construction.

The pool, however, is crystal clear, but always has been. Plaster is noticeably brighter, chlorine really is a wonder element. Small pock stains remain within divots in the plaster around the drain, curved parts and near small tiles. Not wide spread and probably noticeable only to me. I guess I'll be seeing where the drop test leaves me overnight.

Post mortem, I believe my builder gave me inaccurate volume by a significant disparity. I stepped it off myself and he's hundreds of gallons off, signature now reflects these new measurements. I've been putting too little chlorine, which was barely maintaining the minimum and falling beneath as often as above, especially overnight. Based on the advice I've found lurking here, I will be adjusting my test routine to evenings after the SLAM, allowing higher FC levels for longer periods of no UV pressure. Hopefully, I've realized my error and nipped this in the spore.
 
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omayhemo

Active member
Jun 4, 2020
28
Texas
More construction, stone work and shingles. So much asphalt in the pool. Vacuumed 3 times, brushed several, emptied skimmers, etc.
The night before the FC dropped only by 1ppm. The spots look to be fading, but persist. I dosed to shock level again.
 

omayhemo

Active member
Jun 4, 2020
28
Texas
Deluge last night. Unfortunately the new construction, with new shingles, has no gutter and funnels into the pool from the gable that comes together from all points on the roof right over the pool. So all that asphalt and all that water torpedoed my overnight drop test this morning. No idea where I really stand on the SLAM because of it. So dose again and hold out another day.
 

omayhemo

Active member
Jun 4, 2020
28
Texas
Finally a night without rain. Yesterday I maintained SLAM, the morning test was minimal chlorine loss, < .5 CC and crystal clear water. I still have some dotted discolorations I'm keeping an eye on, but I believe the shock is over. The location of these particular dots, right at the place where runoff goes straight off the construction in to the pool, leaves me to wonder metallic stain?
 

omayhemo

Active member
Jun 4, 2020
28
Texas
Just going to tie a bow on this. High bather load last night, minimal drop in FC through out the whole high UV day and over night. I now realize, that since I took over maintenance from the builder's crew, I've been fighting a problem I wasn't aware of. It's clear to me now, because after the SLAM, my FC usage (even through out the day) is incredibly low compared to the large amounts I was going through until now. I should've SLAMed as soon as I took over the maintenance, I'd have saved quite a bit of money in LC. Now I know!