Overnight FC Loss, updated and shocking
Below is the edited text to some PMs between myself and duraleigh. I thought it would be of benefit to share with the whole. Further discussion can be on this thread. Thanks Dave for the help.
______________________________________________________________________________________________________
poolgirl22
Message subject: my chlorine demand Sent: June 3rd, 2010, 10:22 pm
I'm still concerned about my daily FC drop. I hate to obsess over this but truly, I wonder if something needs adjusted that's in the 200 level class range, Kwim? I'm highly embarrassed to be so OCD and don't want to post AGAIN on the board if nothing is wrong.
I'm consistently bringing up at night to 9 (11/12 over the weekend when we had a houseful) FC and by next evening I'm at 4-5.5 even today with only me taking a 15 minute dip and that's it. Less than 1 ppm overnight FC loss. No CCs or .25 at most. Crystal clear, shined like diamonds the last couple days. Very little debris if any. Adding between 3-5 quarts a nite.
I get full sun from mid morning to well into evening.
PH is holding steady at 7.5 (should I try to drop it a bit?)
TA 90 (haven't tried lowering it anymore since PH is holding)
CYA 55 (retested this week. Should I raise this a bit?)
Temps holding around 82-84
I'm confident my gallons are calculated properly because when I add bleach each night it reaches my target or within .5 either way.
My initial thought is maybe I need to run a little higher CYA..maybe 65-70? I know that puts things into a crazy situation if I should need to shock, but as AR as I am about my additions, I don't see that happening...lol...
_______________________________________________________________________________________________________________________________
duraleigh
Message subject: Re: my chlorine demand Sent: June 3rd, 2010, 11:03 pm
Well, that's puzzling. Most of the time 2-3ppm is the loss on a balanced pool with sun. I see nothing in your numbers to raise a flag.
When you dose chlorine in the evening, are you calculating your target or actually testing to see if you got to your target. Bleach not at full strength could cause an issue if you are not testing.
______________________________________________________________________________________________________
poolgirl22
I have been intermittently testing to see if I got to target, and to see if any FC loss. Each time I'm within .5-1 of the target, always over as I sometimes go up to the neck of my measuring bottle rather than right at 32 oz... Our local walmart seems to go through the bleach at a good clip and it's the only place I buy it. Sometimes I have the last 3 or 4 jugs, others, brand new.
I added to get to 9ppm this evening around 9 oclock and I tested just now at 11pm and got a solid 10 ppm, pump ran whole time inbetween and I even brushed the nothingness that was not there.. :lol: Bather load seemed to be the issue over the weekend and last week, but then today when I purposely stalled the days activities and just put myself in for a few minutes it still dropped 5ppm.
Thanks for the help.
______________________________________________________________________________________________
duraleigh
Well, let's review the very basic premise that FC is consumed by organics and sunlight. It makes very little sense that you live closer to the sun than the rest of us so I think we have to suspect organics, even though your overnite FC loss test demonstrated otherwise.
The only logic I can offer in suspecting organics is you seem to have eliminated everything else. Because your FC loss is abnormal but only by just a little bit, it could be the vagaries of the FAS/DPD test may have mislead you just a little when doing the loss test. In other words, you may have lost just a little more overnight than you thought.
I would suggest this...
Tomorrow night (or whenever) elevate your FC to around 12ppm and then check it next AM. If it's less than 11 then I think we can confirm organics.
Even if it doesn't drop much, try to hold your FC at 12 for at least 24 hours....48 would be better. In a 24 hour period, given your parameters, I would expect about a 4ppm chlorine loss from 12. I think (because of organics in your pool) it'll lose more like 6 or so but let's see.
If it does, the answer is to just go ahead and shock again and do the overnight FC loss test probably the second night.
___________________________________________________________________________________________________________
poolgirl22
Message subject: Re: my chlorine demand Sent: June 4th, 2010, 12:05 am
Sounds good. I'm heading to bed in a few minutes...Its 12 am. I'll bump to 12 before I go and retest in AM around 8am and go from there as you outlined. Thanks for the help. When we figure this out we can move to a thread if you wish for the benefit of the whole.
____________________________________________________________________________________________
poolgirl22
Message subject: Re: my chlorine demand Sent: June 4th, 2010, 8:30 am
There we have it! I tested at 8am and sure enough I got 10.5, 11, and 10.5. Yep, did the test 3x. So at least 1, but likely 1.5 overnight. Crud **** ****. I'm not a happy camper this morning, but I took to 18 anyway. Shock commencing through today, tonight, tomorrow and will retest FC loss saturday nite.
Lesson learned. For my pool a loss of FC overnight close to 1 means something is definitely up. Off to tennis and buy more bleach...thanks. I'm good from here I think. I know the drill going forward.
_________________________________________________________________________________________________________________________
poolgirl22
Message subject: Re: my chlorine demand Sent: June 4th, 2010, 3:39 pm
Just an update on how I'm doing.
I had to buy REAL Clorox today... :grrrr: Wally was out of GV. Anyway, I plan to attach the text of our messages to my last thread where we all thought it was just changes in demand. I think my situation is one that is worth sharing with the whole exemplifying that nothing is static and you HAVE to know your pool in order to manage it properly. I've learned a lot from this experience.
I know I'm losing a lot to sunlight right now and of course when the kiddo and I were in messing with the steps and the real progress will be made after dark, but I'm a believer in showing how to really stay after this shocking process.
800am: FC 10.5, added to reach 18 shock level
845am: FC 17, added to reach 18
1045am: FC 17, added to reach 18
1200pm: FC 15, added to reach 18
(removed stairs, scrubbed down, replaced, brushed pool, kiddo splashed around a bit, cleaned skimmer pieces and parts thoroughly)
140pm: FC 13.5, added to 18
315pm: FC 14, added to 18
There have been no CCs at any time.
Thanks again. Will see you and others on the thread.
___________________________________________________________________________________________________
duraleigh
I don't know if we've discussed this....have you looked under your steps? Inside your ladder? any place organics can hide. White mold gets in there a lot.
_________________________________________________________________________________________________________________________
poolgirl22 (received above while typing this post so here's the reply)
Yep, removed, scrubbed, bleached, scrubbed, drilled more vent holes in steps. No ladder. Other than a little organic staining which was removed with magic eraser and/or bleach, Nothing green. And I usually pour some bleach down inside the steps and I move them daily to eliminate any buildup of stuff. Stairs have always been a pain in the ....
I've cleaned the skimmer really well too, especially in between dosages of bleach, and have even poured a couple cups directly into the skimmer each time.
__________________________________________________________________________________________________
