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

[Themadczar]

Ok, i'm a new pool owner (not a new pool). Bought a house with a 14x28 IG pool with vinyl liner, sand filter, heater, and auto-cover. Thpool wasnever opened last year, and this house is in a wooded area. The pool was a mess. After a couple of weeks of work, the water is clear, the debris is gone, but there is still a green tint to the water and the test results are strange. I justgot my talor test kit yesterday, and here are the results...

5/29/13
5pm - temp 70 degrees, fc 6ppm, cc 5ppm, ph 7.9, cya 0.
Then I vacuumed the pool and added 96oz of 6% bleach (around 7:45 pm)
9:45pm - fc 5.5ppm, ph 7.8, ta 320, ch 340

5/30/13
7:15am - fc 7.5, cc 2ppm (that was all i tested this morning)

Not sure what to do next... Shock again to keep reducing cc? When do I add stabilizer (the auto-cover seems to protect the chlorine from uv somewhat... The last time I added bleach was 5/24 and I shocked with 384 oz of 6% bleach)? What do I do about the high ta and ch? Is my pool still a mess even though it looks better? All I have added to the pool since it was opened is hth, bleach, chlorine tabs, and water (city utilities). Any help is appreciated.

[Watermom]

You want to keep the chlorine high (see the Best Guess Chlorine Chart in my signature below for needed levels) until you can go from sundown one evening to within one hour of sunrise the next morning without losing more than 1ppm of FC and your CC level is no higher than 0.5ppm.

What is your source of fill water?

Does the liner feel slippery? Have you brushed the pool?

Welcome to the Pool Forum, by the way!

[PoolDoc]

Assuming you have no algae (slippery sides mentioned by Watermom = beginning algae), then you need to:

1. Get your CYA up.
2. Maintain chlorine levels.
3. Maintain pH in the 7.0 - 7.4 range.
4. Decide what to do about your VERY high TA and CH.
5. Don't worry about the CC levels UNLESS they continue for several days. Make SURE you aren't confusing CC with TC (Total Chlorine = FC + CC).

You can do a bucket test for CH: http://www.poolforum.com/pf2/showthread.php?16992-Lime-Softening-to-Reduce-Excess-Hardness-Bucket-Test-amp-Treatment-Process

And, this page will tell you how to lower your alkalinity. But you do NOT want to lower your alkalinity till AFTER you lower your calcium, if you pursue that option: http://www.poolsolutions.com/gd/lowering-swimming-pool-alkalinity-step-by-step.html

Meanwhile, if you have a Sams membership, consider buying a 50# bucket or 24# box of dichlor. Sams is the ONLY big box store I know of that sells undiluted / unblended dichlor.

[Themadczar]

The wbsite and forum are both extremely helpful! Thanks for the guidance and resources. I will see what I can do now that I have some direction.

[Themadczar]

Assuming you have no algae (slippery sides mentioned by Watermom = beginning algae), then you need to:

1. Get your CYA up. Is there a process for this? Incremental increases over time?
2. Maintain chlorine levels. Ok.
3. Maintain pH in the 7.0 - 7.4 range. Ok.
4. Decide what to do about your VERY high TA and CH. Will read...
5. Don't worry about the CC levels UNLESS they continue for several days. Make SURE you aren't confusing CC with TC (Total Chlorine = FC + CC). Nope... These were the cc results from the testing. Tc would be 11ppm yesterday and 9.5ppm this morning. I will keep monitoring

You can do a bucket test for CH: http://www.poolforum.com/pf2/showthread.php?16992-Lime-Softening-to-Reduce-Excess-Hardness-Bucket-Test-amp-Treatment-Process

And, this page will tell you how to lower your alkalinity. But you do NOT want to lower your alkalinity till AFTER you lower your calcium, if you pursue that option: http://www.poolsolutions.com/gd/lowering-swimming-pool-alkalinity-step-by-step.html

Meanwhile, if you have a Sams membership, consider buying a 50# bucket or 24# box of dichlor. Sams is the ONLY big box store I know of that sells undiluted / unblended dichlor.

[Themadczar]

You want to keep the chlorine high (see the Best Guess Chlorine Chart in my signature below for needed levels) until you can go from sundown one evening to within one hour of sunrise the next morning without losing more than 1ppm of FC and your CC level is no higher than 0.5ppm.

What is your source of fill water? City water

Does the liner feel slippery? Have you brushed the pool? Brushed over the weekend... Will have to feel for slipperiness tonight.

Welcome to the Pool Forum, by the way! Thanks!

[Themadczar]

Liner is not slippery... Checked at lunch.

[Themadczar]

I have 44oz of cya... Do i just follow the procedure here...
http://www.poolforum.com/pf2/showthread.php?15484-Best-Way-to-Add-CYA
All 44 oz at once?

Also, these are my chlorine levels... Does this make sense?
5/29
5pm fc is 6 ppm, cc is 5 ppm
8pm added 96 oz. 6% bleach
10pm fc is 5.5
5/30
7am fc is 7.5, cc is 2
7:30pm fc is 2.5, cc is 7.5. Then added 384 oz bleach
8:30pm fc is 9.5, cc is 5
5/31
7am fc is 4.5, cc is 9
6:30pm fc is4, cc is 10. Then added 384 oz bleach
10pm fc is 5, cc is 12.5
6/1
7am fc is 5, cc is 11
6pm fc is 14, cc is 5
Numbers seem to be all over the place.... Not sure what to do now.

And finally, another question... Sounds like my pump motor is going bad (getting louder, whining noises, and hot to the touch). However, I cannot seem to determine the hp of the motor so I can get a replacement. Hayward Super Pump. Any ideas? Thanks yet again.

[Themadczar]

6/1
10pm shut off pump
6/2
8am fc is 14, cc is 5. Started pump back up (still loud)

[PoolDoc]

There should be a label on the MOTOR (the hot part). There also should be another label on the pump casing (the part that has water in it). If you can post photos of both labels with Flickr, Photobucket, Webshots, Picasa, or Facebook, we can probably work out what size motor you have.

[Themadczar]

I reposted the motor question in the pool equipment section with more details... I did find a model # on the motor (sp2600zlc) but after searching the web, i still cannot determine the hp. If that's still not enough info, i will post photos.

[PoolDoc]

Hayward motors will have a SP number, but for example, a SP2610x15 is a 1HP pump that gets uprated as a 1.5HP pump.

[Themadczar]

Ok, to keep things tidy, i will continue the motor discussion here:
http://www.poolforum.com/pf2/showthread.php?20199-Motor-size&highlight=
And it siezed this afternoon...

Back to test results... Any answers to the questions/situation below? More importantly, what can i do while I'm replacing the motor to keep things improving or at least prevent them from getting worse?


I have 44oz of cya... Do i just follow the procedure here...
http://www.poolforum.com/pf2/showthread.php?15484-Best-Way-to-Add-CYA
All 44 oz at once?

Also, these are my chlorine levels... Does this make sense?
5/29
5pm fc is 6 ppm, cc is 5 ppm
8pm added 96 oz. 6% bleach
10pm fc is 5.5
5/30
7am fc is 7.5, cc is 2
7:30pm fc is 2.5, cc is 7.5. Then added 384 oz bleach
8:30pm fc is 9.5, cc is 5
5/31
7am fc is 4.5, cc is 9
6:30pm fc is4, cc is 10. Then added 384 oz bleach
10pm fc is 5, cc is 12.5
6/1
7am fc is 5, cc is 11
6pm fc is 14, cc is 5
Numbers seem to be all over the place.... Not sure what to do now.

[PoolDoc]

Back to test results... More importantly, what can i do while I'm replacing the motor to keep things improving or at least prevent them from getting worse?



1. Get your CYA up.
2. Maintain chlorine levels.
3. Maintain pH in the 7.0 - 7.4 range.

Use dichlor, which will add CYA and keep the pH down. Sams Club is likely the only reasonably priced source of undiluted / unblended dichlor.

Use bleach till you can get some dichlor.

[Themadczar]

6/1
7am fc is 5, cc is 11
6pm fc is 14, cc is 5
10pm shut off pump
6/2
8am fc is 14, cc is 5. Started pump back up (still loud)
5pm pump motor seized
9:30pm fc is 10, cc is 4
6/3
8am fc is 5, cc is 10
7:30pm fc is 12, cc is 3.
Why are the fc and cc levels fluctuating so widely when the last time I added bleach was 5/31 at 6:30pm? It seems that in the morning fc is low and cc is high, but in the evening the levels flip to high fc and lower cc... And how does fc jump from 5ppm in the morning to 12ppm in the evening without introducing any chlorine? I'm just not understanding.

Still working on getting 1) a new motor 2) dichlor... In the meantime I added 2 more gallons of bleach tonight and vacuumed with a catfish to clean up some debris and move some water.

[Themadczar]

Update... Pump motor replaced and running again. Reagents delivered (ran out of 8071 already). And i have dichlor. Back in business.
Added 2lbs dichlor last night.
Tested at 9pm tonight.
Fc=4.5
Cc=10
Ph=7.2
Ta=300
Ch=350
Cya= about 10 (too low to measure, but some is present now and the 2lbs of dichlor should amount to 9.6ppm)
Added 3 more lbs of dichlor tonight.

Retested at 10pm
Fc=6.0
Cc=19

I will retest in the morning... Anything else I should do?

[Themadczar]

7:30am
Fc 3
Cc 15
Very frustrating.

[BigDave]

If you'd like to work up an estimate of how much chlorine will be required to clean up your pool, perhaps you could try: Bucket testing for chlorine demand (http://www.poolforum.com/pf2/showthread.php?16973-Bucket-testing-for-chlorine-demand).

Be calm. Frustration and impatience very often drive us to look for a "Magic Fix". "Magic" is never what it appears to be and in a pool usually makes the mess worse and the cleanup longer and more expensive.

[Watermom]

How are you testing for CC? Your numbers are bizarre. How does the water look?

[Themadczar]

Water is clear with a very light green tinge. Sides are not slippery, and brush is never green after brushing the pool. Normal taylor 2006 test process... 10ml pool water. Scoop of powder (turns red). Count drops of 0871 until it stays clear. Each drop is .5ppm fc. Add 5 drops of 0003 (turns red again). Count drops of 0871 until it turns clear again. Each drop is .5 ppm cc.
I know the numbers are bizarre. That's why i keep posting/updating here. :)
I intend to add 4 gal of bleach tonight unless someone suggests differently...

[PoolDoc]

Sorry I hadn't picked up on this sooner.

You are almost certainly experiencing the well-established problem of cyanuric acid conversion to ammonia or urea by bacteria. This results in the HUGE chlorine demand, and high CC levels, you are seeing. There are only two solutions: (a) drain and refill - NOT safe on vinyl IG pools, OR (b) chlorinate until the demand is gone.

You can use the bucket test BigDave described to answer, approximately, the question, "How much more chlorine will it take?". Or you can just chlorinate till it's done.

For a variety of reasons, you are probably better off doing this at a higher than normal pH, but you can't go very high with Alk and CH over 300 ppm. So, I'd recommend using borax to push the pH to ~7.6, and holding there till you get the situation under control.

Do NOT swim while you are doing this. High chlorine is rarely a problem for people, but high chloramine levels are something different.

Adding CYA will slow the process at this point. My recommendation would be to
1. Use borax to raise the pH to 7.6, and hold it there.
2. Dose each evening with 4 gallons of household bleach UNLESS the TOTAL chlorine (FC + CC) is greater than 20 ppm. Skip doses when TC levels are above 20 ppm.
3. Use the bucket test if you want to find out how much longer you have to go.

Sorry about this. We had many, many cases last year, with the super-warm spring of 2012. This year, with a record cold spring, there have been very few cases.

[Leehicks79]

Scoop of powder (turns red). Count drops of 0871 until it stays ...

Shouldn't it be TWO scoops of powder?

[BigDave]

if it turns pink, one is enough.

[Themadczar]

Ok, thanks. At least i know what I'm dealing with. However I have added 5lbs of dichlor in the last few days... My cya should be around 23 (I'll test tonight unless it takes longer to fully dissolve and I would just be wasting reagents). Does that change your recommended evening dose of chlorine, PoolDoc?

[PoolDoc]

Not really.

CYA may slow the reaction of chlorine with ammonia, but not by much.

[Themadczar]

Added 1 cup of borax to the skimmer... Will check ph tomorrow night and act accordingly. And 4 gal of bleach will be going in shortly, then I will check tc tomorrow night as well. Thanks for the help. I'll let you know if anything else comes up.

[Watermom]

By the way in case we haven't said it before, thanks for the subscription. We appreciate the financial support to keep this forum alive!

[Themadczar]

One more question... How do I know when the process is complete? Cc down to 0?

[Watermom]

Yes, and no more than a 1ppm drop in chlorine from sundown one evening to within one hour after sunrise the next day plus having clear water. We then usually recommend holding the chlorine high for one additional day for added insurance and then let it drift down and keep it in the appropriate range based on your CYA level.

[Themadczar]

Update...
Still feeding the chlorine demand. 5# of dichlor and 39 gal. of bleach (or about 162ppm of chlorine) so far. Just got back from a week long vacation, and things are no worse than when we left. I had our friend who watched our dog dump in partial doses (1-2 gal of bleach per day) while we were gone. FC last night was 5.0 and CC was 18.5. I will continue to chlorinate. Hopefully we are nearing the end. We would like to swim this summer. :-/
(I decided not to waste my time/reagents on the bucket test. The results don't change anything. It will be done when it's done.)

[Themadczar]

I don't get it... Both my fc and cc are staying pretty consistent, but they are still not where they should be. Since getting home from vacation, fc isn't dropping below 4, but cc is staying in the high teens. See below...

Date_ time_ FC_ pH_ CC

2013-06-23_ 00:10_ 5.0_ 7.7_ 18.5
2013-06-23_ 19:05_ 6.0_ 7.7_ 12.5_ added 384oz 6% bleach
2013-06-24_ 18:13_ 4.5_ 7.7_ 19.0
2013-06-25_ 19:42_ 4.5_ 7.7_ 16.0_ added 192oz 6% bleach (1/2 dose since already over 20ppm)
2013-06-26_ 17:38_ 4.5_ 7.7_ 19.5_ added 192oz 6% bleach (1/2 dose since already over 20ppm)
2013-06-27_ 18:58_ 5.0_ 7.8_ 19.0

I can't add more bleach (already over 20ppm tc), but doesn't seem to be making progress either. And ph has creeped up to 7.8. Any idea what I should be doing at this point? This is getting really frustrating. Pool open for over 2 months and we still can't swim in it.

[PoolDoc]

It's a terribly frustrating problem, but one without any easy solution. We had dozens of cases of this, last season after one of the warmest springs on record, and only a handful this year, after one of the coldest springs.

But, since you are one of the few, there's no consolation in that.

It doesn't appear that you have raised your CYA much, and unless you do so, it's risky to run higher chlorine levels. I'd recommended using dichlor, for that reason, but at this point, I believe you'd be better off buying a bucket of 40# of trichlor at Sams Club, and running those in your skimmer. That way, you can run chlorine levels higher than 25 ppm in your pipes and your filter, without running higher than that in the pool. That will add CYA and probably accelerate the decomposition of the the combined chlorine.

We've mentioned a bucket test, several times. If you want to know how much longer, that's the way to find the answer. Otherwise, you'll just have to plug along till it's done . . . whether it takes a week more, or a month more.

The only other practical way to remove the ammonia that I know of is biological -- which would mean allowing your pool to turn to a slime pit for a week or more. You'd have to buy an ammonia test kit, so you'd be able to see when the biological removal of ammonia was complete. And then, you'd have a week or two of clean-up.

You can also do an in-pool drain, if you buy a small sump pump, and a tarp that's 15' larger than your pool in all directions (20' x 50' tarp!). If you are interested, I'll explain.

But I don't know of any easy or pleasant fix.

[BigDave]

Maybe I missed it, but, I don't recall seeing a CYA reading for a while. There was 0 CYA at the beginning of the thread and 5 lbs dichlor added so I'm guessing 20-25 ppm CYA?

Is the pool covered (also sorry if I missed it)?

[Themadczar]

I am mostly just venting/complaining... But i truly don't understand why I'm maintaining 4-5ppm fc while cc is also staying in the high teens. The bucket test might tell me when to expect the light at the end of he tunnel but it doesn't get me there any quicker. I suppose I will just keep plugging away...
As for CYA, poolcalc says I should have 23ppm, but I haven't tested since right after adding the dichlor. Should I do so now? And the pool is covered most of the time. It's an auto-cover, but without a fence I have to keep it closed when I'm not around (neighbor has a toddler). I have been trying to leave it open as much as possible though.
Getting to Sam's is not easy, and I still have 19 lbs of dichlor. Until I can get the trichlor, what do you recommend? And how does putting trichlor run higher CL through pipes/filter but not the pool?
And thanks for all the help!

[Themadczar]

Ok, based on BigDave's questions, I included cya in my testing tonight. Riddle me this... How could I have no measurable cya in the pool when I first tested it, then the only cya added was in the 5# of dichlor I put in a few weeks ago which amounts to about 23ppm. Now my cya is over 50ppm. Where did the other 27 ppm come from?
I am assuming that the higher than expected cya number explains why chlorine levels are not dropping much during the day when I have been able to keep it uncovered... For example, last night I had 5ppm fc and 19ppm cc, but tonight after leaving the cover off all of today and it being a bright, sunny day, fc was 4.5 and cc was 15.5 (i didn't add anything last night after testing).
So now, if I understand correctly, i should take my tc up to 30ppm (by adding 8-9 qts of 6% bleach), right?

[PoolDoc]

I don't have answers to all your questions, but I'd caution you not to go to FC>30 ppm with a vinyl pool, when your CYA levels are doubtful.

If you want a more trustworthy CYA test, take a open glass container (1 qt measuring cup?), fill it with pool water, and set in the sun. After the chlorine level (TC) is below 3ppm, use the sample to test for CYA and see what you get.

[Themadczar]

I appreciate the honesty. And I will work on the cya test today. To add to my confusion... I tested the water today and fc was 3.5, cc was 17.5. No surprises there. But when I checked tc with my oto kit, it was about 2 (definitely not as dark yellow as the 3ppm color). I have never seen my oto kit go higher than 2, but I know my tc is over 20. Is the reagent bad? It's a new kit early this season.

[PoolDoc]

DPD FC + CC *should equal* OTO after 10 minutes.

Might want to check that. If not, we've got a mystery we need to look into.

[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?
https://www.dropbox.com/s/akwxaa4ulf04fzo/IMG_20130630_125424.jpg
And this is a pic of my cc test turning yellow after adding the r-0003 reagent...
https://www.dropbox.com/s/muzinp3acdwml4p/IMG_20130629_231701.jpg

[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.

[PoolDoc]

Get some polyquat as quickly as you can, and add it. You have no circulation in the water on the cover; it will turn green quickly if you don't treat it. www.poolsolutions.com/polyquat.html

Meanwhile add 1/4 - 1/2 gallon doses of bleach each evening. Or, if you have some dichlor, you can use that. Do NOT use trichlor or cal hypo -- either could burn through the tarp, which usually not very chemical resistant.

By the way, I'd be grateful if you can get a series of pictures of the whole process -- many people have a hard time getting a clear idea of what we mean, when we describe this.

[Themadczar]

The process will be complete this afternoon... It was a 24-26 hour process at my flow rate so the pump will go back on this evening. And since I have already added 2# of dichlor [fc of the new water was 14.5 this morning and cc was 0!!! :-)] I think I can skip the polyquat (I'll be all done and the pool circulating & chlorinated before I could even get the polyquat). I have a few pics... How can I get them to you?

[Watermom]

You can either post the pics with flicker, picassa, etc. or email them to poolforum@gmail.com and reference the url of this thread.

[Themadczar]

Huge success! Wish I had done this a month ago! Here's an overview of the MDR process...

What you will need:
Tarp or plastic sheeting at least 15' larger than your pool dimensions in both directions.
Bottom drain and/or submersible pump
Garden hoses
Clean 5 gal bucket
Enough dichlor to get your pool to shock level (and eventually bring cya to desired level)
Poly quat (if your pool will take several days to fill)
Borax (and whatever other chemicals your tesing reveals you will need)
Taylor 2006 test kit (of course)
Something to keep the tarp from your vac ports/drain (I used a large plasic leaf rake... It worked to guard the sidewall vac port I used for part of the time. But you might need something different...)
Heavy objects to weigh down the edges of the tarp

Prep work (this is what I did for my setup... Yours might need to be different. Plan ahead and give yourself multiple options to add water and remove water):
1. First of all, I tested my fill water so I knew how I would need to treat it.
2. I tied a string to my pole and lowered the whole thing with the vac head attached to the bottom of the deepest part of the pool. I tied the other end of the string to the hose right abobe the skimmer so I could pull the pole and vac back up when I was done. I have no bottom drain so this was my backup method of water removal if the pump should fail or I needed to dump water quickly by vacuuming to waste)
3. I placed the submersible pump at the deepeat part of the pool.
4. Also, I put a garden hose in the pool after filling with water from a jet... This would be my syphon hose (we live on a ravine so gravity woul be my friend)
5. For my fill water, I connected hoses to both outside spigots... This doubled the rate of filling. If you have 3, use them all.
6. Finally I positioned the tarp over the pool with my daughter's help.

Process:
This part was pretty easy... After getting the hoses started filling water on top of the tarp and the submersible pump & syphon pulling water from under the tarp, i also pulled water through the side vac port with the pool pump (to waste). I used the pool pump until the water was just above the side port (about 12" below normal) then I shut off the pump. At this point, the fill was just barely faster than the pump and syphon, so it was fine to leave it awhile. As the water level got too high I would use the pool pump to remove water to just above the port again. This is where the rake came in... I placed it upside down under the tarp with the handle on the bottom of the pool and the tines resting on the side just above the port. It was at about a 45 degree angle. This seemed to keep the tarp far enough from the port to prevent it from cutting off the flow to the pump (at least until it was about 2/3 done).
The difference in flow rates was small enough that I could go 6-8 hours between using the pool pump to lower the water level again. this would be much harder if the outflow was faster than inflow... My submersible pump is very small and might be about the same flow rate as the water supply... Syphoning however was not nearly as fast as the supply.
When it was about 1/3 complete I pre-dissolved 1 lb of dichlor in a clean 5 gallon bucket (for my pool it would take 3 lbs of dichlor to get me to 15ppm of chlorine upon completion, so 1 at 1/3, 1 at 2/3, and 1 at completion.). I then poured this around the pool. Also, my fill water has very high alkalinity so I tried to keep the fill hoses elevated so that they aerated the water some as they filled the pool plus this provided some movement of the water since there is no other dcirculation during this process.
Almost all 13000 gallons had been replaced in about 24 hours from starting the hoses. Removing the tarp was a little tricky... My daughter was eager to get in despite the 71 degree water, so she helped from the inside. (it is worthy to note that the heat transfer from the old water to new was higher than expected. I thought I would be starting with 60 or 65 degree water, so 71 was great.) the trick is to get the tarp fully submerged on one end then slowly drag it to to other end of the pool where it is pretty east to remove once you get the hang of it. Once the tarp was out, we jumped in. Water was great (if a little chilly).