New numbers, might need some direction

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KenV

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Jul 2, 2010
30
Hey all!

I've been using all manner of heck out of my TF100XL kit. We're on the tail end of shocking after the algae mounted its last challenge. Here are my numbers:

FC 8.5
CC 1.5
TC 10 (well, duh, yeah...)
Ph 7.7
CYA 25
TA 200 (yes, two hundred)
CH 240

Chlorine is high since we're coming off that shocking, but the Ph seems a bit high, even though I've already added a gallon of Muriatic Acid over the last week to get it to the 7.7 figure (it was about 8). Of course, the splash of acid brought the TA to a not-so-stratospheric level (down from 350, holy carp!) but I want to know if there's anything I should watch/change going forward.

All that's left to do after this is stable is cut back the palm tree that overhangs it, choose the cover and grab some equipment (auto cleaner). Loving this pool, especially the spa. :whoot:
 
High chlorine will cause pH to read high. Have you passed the overnight FC loss test? Once you pass that you can allow the FC to drop down to normal levels and work on lowering the TA.
 
Ken, welcome to the forum. I'd like to know where you are located, that TA sounds like my area. In the user control panel you will find a section to let you add a location so that it shows up with your name.

Do what you can to get help here on estimating the pool volume. As you reduce that TA, the muriatic acid you add will affect the pH more and more. You don't want to suddenly go so low as to create problems with the pool; metals from the heater or plaster pitting in the pool itself.

As for that palm, it may offer needed shade to keep summer water temps in a nice range. I do miss the Giant Bird of Paradise that hung over my pool, lost to this past winter's cold snap. The pool was noticeably warmer without that shade.
 
Thanks for the idea. I know it was losing half its FC per night when it was high (I had it at 20 for a few days to make sure I was whacking the algae) but it only lost 2ppm since Monday night. I'll hit it every night without adding anything and report back. Thanks again!

anonapersona: I'm in the east end of Bakersfield, CA, on a well. Not sure how I skipped adding a location, something I'll fix when done here.

The pool is a 37' x 22' kidney with a spa, and my best estimate was 25-30K gallons when last I tried. Funny thing, the pH seems to actually rise over time if left alone. Not so much since I shocked however. When I treated with acid I used 30K as a volume and it had the proper result per the Pool Calculator. Maybe I'm close enough for this, not sure.

I was worried that the palm was dropping too much organic waste into the pool, but the skimmer is catching most of it. I'll keep the palm but will trim the bottom levels and wash it down after I get a pool cover. To be honest I'd rather have a BoP as you did since they make less of a mess. Then again, there's a mating pair of doves in the palm and they poo like they're being paid to do so. Not in the water, from what I can tell, but a lot of fluff and stuff falls from the tree.
 
Thanks Sportsman, and howdy right back at you.

With our initial fill having been 350 I had my work cut out for me. I paid $12 to fill it so I won't complain about chem costs, or aeration if ever I need to build a pipe. Heck, I already have the pipe and compounds.
 
but I want to know if there's anything I should watch/change going forward.
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A CC's test result of 1.5 indicates you are not done shocking your pool. Generally, you are finished when....
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.

I would suggest you re-elevate your FC back up to around 10-12ppm and finish the process.
 
Roger that, thanks Dave. So far #1 is true but to see about #3 for sure I need to head out and check my numbers after I put my daughter to bed. Hopefully we'll be okay to dip this weekend....

I thought CC was determined by CYA. What am I missing here?
 
KenV said:
I thought CC was determined by CYA. What am I missing here?
Click to expand...

CC is the byproduct of chlorine after it has been used, but it is not quite gone. Sometimes you see it sometimes you don't. Air and sunlight reduce CC, and more chlorine speeds that along. It is some of the nasty pool smell you get from some pools. That harsh chlorine smell is CC. It can be harsh on the eyes and skin. We don't like to swim in it.

Dave can give a better explanation, I'm just pitching in.
 

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Anon: I thought that CC was held over by CYA for the sake of 'reserving' chlorine to replace what gets lost over time. Obviously I need to figure that out more.

Just tested:

FC 6.5
CC .5

Bear in mind it was about 100 degrees today and the pool gets full sun as the palm only overhangs a couple of feet of one 'bank' of the pool. Just added some liquid CL to boost it and will test later. The Pool Calc recommended 1.6 gallons of the 10% stuff but I put two gallons total in tonight. Wifey and I will keep it at this through tomorrow and see what we get. I still need to research the CYA effect on CC.

One thing I neglected to mention: Due to our work schedules I've only tested every 24 hours. Same time, each night. So the 2ppm drop is over a full day. I know we should be testing a few times per day but it isn't as easy to do right now for several reasons...we're getting there though! Thanks again for the help.

Edit: The pool smells nice. No heavy chlorine smell, and the water feels fine when I take the test swipe. I can let it dry on my arm and there's no odor or after-effect. So at least I'm not poisoning myself! heh
 
KenV said:
Anon: I thought that CC was held over by CYA for the sake of 'reserving' chlorine to replace what gets lost over time.
Click to expand...
The chlorine bound to CYA that is in "reserve" gets measured as Free Chlorine (FC). This is because it gets released in the time of the test. Half of the bound chlorine gets released every 1/4 second if there is no active chlorine left (i.e. if the active chlorine has reacted with the dye in the FC test). Even though the chlorine gets released quickly, it is the active (unbound) chlorine level that determines the rate of disinfection and killing of algae. It's like having lots of soldiers in reserve that aren't on the front lines fighting -- it doesn't matter how many people you have in reserve nor how quickly they can replace someone killed on the front lines; the rate of killing the enemy is determined solely by the number of people on the front-lines (shooting).

Combined Chlorine (CC) is chlorine that is more tightly bound to other chemicals and requires the R-0003 reagent (potassium iodide) to release it reacting with the iodide to form iodine that is what reacts with the dye. Chlorine that is bound to ammonia, urea and many other organics (but not CYA) gets measured as CC.
 
Let me see if I have this right: The hit of DPD makes the chlorine visible, the 0871 measurement shows me how much chlorine is available to fight in teh absence of ammonia/organics, and the R-0003 acts like ammonia and other organics do in the actual pool?

I am only at 7.5 FC (with barely .5ppm CC after three test samples) So I'm going to load up the water a bit more and test tomorrow, a few times per day.

Thanks chem geek. Fingers crossed.
 
Close, but not quite. The DPD makes the chlorine visible, both the active chlorine and the chlorine reserve. The R-0871 lets you measure how much that is by counting the drops. There could still be organics in the pool since they don't all react quickly with chlorine. The R-0003 reacts with any remaining chlorine that is already bound to ammonia or organics, but doesn't measure ammonia or organics directly. So there can still be organics in the pool that you don't measure.

The way you can get an indirect measurement of organics that slowly react with chlorine in your pool is by Performing the Overnight FC Loss Test. You don't need to do this unless you see an unusually high chlorine demand or you are shocking the pool and want to know when you are done with that process. As Dave (duraleigh) wrote, the overnight FC drop <= 1 ppm is one of the three indicators that let you know you are done shocking.

You're doing great and it sounds like you are nearly done shocking as your CC has come down as well and is <= 0.5 ppm. How's your water look? Is it cloudy, dull, or clear?
 
Hey folks.

I took the readings last night shortly after dark, and this morning before the sun hit the pool area. Both are averages of three runs through the FAS-DPD test.

Last night: 42+1=43, so 21.5 (Yeah, I spiked the chlorine to make sure I killed everything...)
This morning: 38.3+1.3=39.7, so 19.85.

That nets me a 1.65ppm drop overnight. I'm giving it another night after adding some more bleach tonight, and will maintain until Friday night where I'll repeat the overnight test. The bleach is still quite cheap so I don't mind hammering on it for a few more days. Heck, it's necessary anyway.

Weird thing: My pH keeps rising to 7.7/7.8, and has done so three or more times over the last month. I knock it down with muriatic acid. My total alkalinity was stupid high back then....any ideas? I thought I should check here and think it over some more. Off to bbq!
 
Well, I still have some work to do. TC dropped a total of 3ppm overnight. pH is at 7.8. The water looks so clear it'd be invisible if it didn't refract light.

We haven't had anyone in it since I began this testing, however we had a huge dust storm mid-week. (I have to head out for a bit but will rake/vacuum and hit the CL again when I return.) Could what was blown into the pool (a few leaves, couple small twigs, and of course dust) diminish the CL?
 
Make sure you clear out the old DE in your filter now that you are close to completing the shock process. I have had green, nasty DE clinging to the grids after all the algae was dead. Also be sure to brush well any light niches, ladders or steps you may have in the pool since those places can harbor deposits of algae.
 
Thanks for the tech (Dave)and idea (zea3). I'm maintaining the shock and will pull the filter apart once I get a gasket.

That brings up a new question: This filter is an old Anthony Apollo and I figure the gasket will be trashed when I pull this apart. Is there a recommended site for parts on TFP? I'd like to support a vendor on here. I'll order tonight to get things rolling. Thanks again.
 

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