Strange test results -- very high combined chlorine (CC)

[Themadczar]

Not sure I'm following you... Do you mean I should read the oto test after 10 minutes and that should give a tc reading that will match immediate dpd results?
Also, I don't know if this adds another piece to the puzzle or confuses things further, but I just tested the CL again about an hour after adding 192oz of bleach. I pulled a sample from the pool in a measuring cup like I always do and ran the same dpd test 4 times with 4 completely different results:
1. Fc 5, when I added r-0003 for cc the sample turned a light yellow, not pink. I have had this happen once before, so I retested (assuming I did something wrong)
2. Fc 22, cc 1.5... Huh? Retest again...
3. Fc 7, cc light yellow/peach????
4. Fc 15, cc 7
All 4 tests were done within minutes from the same sample of pool water, and I rinsed with filtered water between tests. This stuff should be pretty simple, and I'm a pretty smart guy, but I am completely lost here.

[Themadczar]

Not sure I'm following you... Do you mean I should read the oto test after 10 minutes and that should give a tc reading that will match immediate dpd results?

If I got that correct, then after waiting 10 min, the oto test was definitely darker yellow than the 3ppm mark (the highest on my test) but not by much... I would think 20ppm or so would be much darker yellow or brown, but maybe I'm wrong.

[PoolDoc]

If you can, take pictures and post them or send them to me. I haven't seen a yellow CC result with DPD-FAS testing.

And yes, I meant, let the pool water + OTO sample stand for 10 minutes before trying to read it.

You can probably resolve some of the DPD-FAS testing confusion by buying a gallon of distilled water from Walmart and mixing 1/2 cup of pool water with 1/2 cup of distilled water, and then testing THAT, for FC, CC, and pH. Multiply the FC & CC results x2; take the pH result as is.

[Themadczar]

I sent the photo in a reply email to the forum notification... Not sure if you will get that. If not,let me know how to send it.

I am seriously considering the in-pool drain/refill. After 3 tsp of bleach into the bucket test, I am still at about 3ppm (immediate... It's dark yellow or borderline orange after 10 min) with the oto test. (Do I move on to the next step now, or add another tsp bleach so that immediate results are orange?) So 60ppm just for step 1 so far.
I tested the water supply today. 0 chlorine (filtered out and no bypass available), no ch, 320 ta, 7.0 ph. So if I refill the pool, a tarp is $65, the water will cost about $50, and I already have dichlor, bleach, & borax. Refilling should eliminate all of the problems I'm having except ta (ammonia, hardness, who knows what else is in the water). If I go this route, would you recommend 100% refill, or would something like 75% be enough?

[Themadczar]

Ok, i didn't have distilled water, but I did it with RO filtered water (0 chlorine and ph of 7.0) and I got 15 fc (7.5 x 2) and 10 cc (5.0 x 2). Ph was below 7 though... How is that possible? Argh!

[Themadczar]

When testing for cc in my bucket test, I got a yellow result last night AND this morning immediately after adding the r-0003 reagent. I suspect this indicates that my cc is off-the-charts high. So I experimented a little this morning... I went ahead and started adding r-0871. Each drop swirled pink before the sample turned yellow again... This happened until about drop 40 when the sample finally stayed pink. I kept adding reagent until i hit drop 80, but the sample was still pink. So, either my bucket test has cc over 40 ppm, or something else is going on here. FC was 6.0 btw.

[Themadczar]

Well, I decided to start the in-pool drain or as I like to call it, the membrane divided refill (mdr for short). I will attach a picture if I can get it to work. I'm using a 30x50 tarp from menards... On sale today for $50! I'm filling with 2 hoses at 8.6 gpm (it's all running through my softener/carbon filter since I have no easy way to bypass it... The softener tells me the flow rate.) I pumped to waste as far down as I could (no bottom drain) and I'm running a small submersible pump in the deepest part of the pool. I believe that with 2hoses, my input rate will exceed my output rate, so I will be adding a syphon later today when I get another hose (we live on the edge of a ravine). Also, I lowered the vacuum head/pole to the bottom of the pool (tied a string around the pole so I can retrieve it easily)... This way, in a pinch, I can start the pump back up with the vacuum hose in the skimmer and pull water from the bottom of the pool. I will keep my progress posted here. Let me know if I'm missing anything. One question... At what point should I add dichlor, bleach, or both to the fresh water? And how much to get things rolling nicely?

And this is a pic of my cc test turning yellow after adding the r-0003 reagent...

[Themadczar]

8 hours in and things are progressing nicely. I have a hose syphoning to the ravine and another pumpin water. With 2fill hoses, I figure that water is still going in faster than it's coming out, but the difference in rates should be pretty small and easy to correct. At about the 1/3 mark, i added 1# of pre-dissolved dichlor. i plan on another at about 2/3, and another at the end. Then I'll test the water completely tomorrow night and adjust everything as needed. With high alkilinity fill water, I'm aerating as I go by letting the hoses splash into the pool... Hopefully this will bring the PH up within acceptable range for restarting the pump/filter. Again, let me know if there is anything else I can be doing.

[waterbear]

Not sure I'm following you... Do you mean I should read the oto test after 10 minutes and that should give a tc reading that will match immediate dpd results?
Yes
Also, I don't know if this adds another piece to the puzzle or confuses things further, but I just tested the CL again about an hour after adding 192oz of bleach. I pulled a sample from the pool in a measuring cup like I always do and ran the same dpd test 4 times with 4 completely different results:
1. Fc 5, when I added r-0003 for cc the sample turned a light yellow, not pink. I have had this happen once before, so I retested (assuming I did something wrong)
DPD bleachout caused by high chlorine levels
2. Fc 22, cc 1.5... Huh? Retest again...
Probably close to what your levels actually are but still bleaching out a bit.
3. Fc 7, cc light yellow/peach????
DPD bleachout caused by high chlorine levels!
4. Fc 15, cc 7
All 4 tests were done within minutes from the same sample of pool water, and I rinsed with filtered water between tests. This stuff should be pretty simple, and I'm a pretty smart guy, but I am completely lost here.

Try diluting a sample of pool water with an equal amount of distilled water and testing that with the FAS-DPD test and multiply that test results by 2 to see what you get.
Re: the autocover...are you leaving the pool uncovered? If a pool is kept covered it is not uncommon for there to be a persistent high CC problem since there is limited offgassing of the disinfection byproducts and exposure to sunlight also is an integral part of the process of destroying CC (which is why persistent CC is a problem in most indoor pools!)