CYA disappeard ove the winter?

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Re: Getting on the right track: calcium high, monopersulface residual reading, and m

Yes, with circulation you should be able to test within a half hour of adding chlorine to the pool. With not great circulation, you could wait an hour instead.

Non-chlorine shock (MPS) will not go away on its own unless there is something to oxidize. If you severely overdosed, it will stick around for quite some time.

MPS at usual dosages will not directly react with DPD so does not measure as FC in that test but it definitely reacts with the potassium iodide in the CC test. However, if you are using a FAS-DPD test (as with the TF-100) then if there is any chlorine at all then your FAS drops will also end up measuring the MPS. This is the pink that keeps returning effect that you are seeing. If you were to do the FC test as normal, meaning the clear needs to remain clear for a bit of time, then you'd end up (slowly) measuring all the MPS as FC.

In your case with probably rather high MPS levels, the MPS itself can also react some with the DPD to show up as FC even if no chlorine is present. Basically, having a lot of MPS in the water wrecks havoc with testing.

The Taylor K-2042 kit has an MPS interference remover that may let you test your pool yourself in spite of the MPS levels in it. I suggest you get that so that you can do better testing yourself.

It may be possible to get rid of the MPS by using a reducing agent to remove all oxidizers from the pool, but of course that would put your pool at risk for developing algae during that period of time. Hydrogen peroxide may be able to be used for this purpose (such as in Baquacil Oxidizer -- NOT CDX), but I don't know how quickly the MPS and hydrogen peroxide react with each other (I've asked Dupont, but they don't know). So this technique would be experimental -- probably only worth it if you were truly desperate to get rid of the MPS in your water. I think you should get the K-2042 kit and eventually the MPS will decline over time though it could take a while.
 
Re: Getting on the right track: calcium high, monopersulface residual reading, and m

Thanks, chem geek. MPS seems to be a problem. Do you agree that I should continue the chlorination to get FC to 5ppm? or am I fighting blind due to the MPS?
 
Re: Getting on the right track: calcium high, monopersulface residual reading, and m

You are somewhat fighting blind, but it probably won't hurt to add chlorine since you've got CYA in the water. I'd just get the interference remover soon so you'll then know the true amount of Free Chlorine (FC) and Combined Chlorine (CC) in you water. It will also tell you how much MPS you've got so will have some idea of how long it might take to get rid of if you keep track of how it drops over time.
 
Re: Getting on the right track: calcium high, monopersulface residual reading, and m

I added 2 gallons of liquid chlorine to finally get the FC to 4.5 ppm(from 1.5 ppm) at midnight last night. I used the TF-100 test this morning (7 a.m.) and had the following results:
FC = 4.5 ppm
CC = 9 ppm
Alkalinity = 250 (question: when nearing the end, I get a flash of red, then the solution reverts to a clear/grayish. Is this the endpoint, or is it when the solution remains red?)
pH = 7.2
CYA just about 20

So things are looking up, though I'm concerned about the CC, which of course is distorted by the MPS. The alkalinity is coming down. We're taking it easy in increasing the CYA after our bad experience last year. Does stabilizer have a shelf-life? ours is probably 2 yrs old.
 
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Re: Getting on the right track: calcium high, monopersulface residual reading, and m

I am not aware of a shelf life for CYA. I never noticed any dates on the bottles or recall reading about it here.

Here is a link to video instructions for the test that might help with your test questions. https://www.youtube.com/user/tf100testkit?feature=results_main
 
Re: Getting on the right track: calcium high, monopersulface residual reading, and m

I have ordered the MPS interference remover, but in the meantime, I'm adding about 2 gallons of liquid chlorine every evening to get the FC up to 4.5 - 5 ppm. I have the sinking feeling that this is adding to our CC, which is steadily increasing and is now about 8.5 ppm (using TF-100 test kit) Again, no idea about the effect MPS is having. Should I keep adding so much chlorine until I get the MPS interference remover?

P.S. Water is crystal clear, no odors, no stinging.
 
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Re: Getting on the right track: calcium high, monopersulface residual reading, and m

Yes, you need to maintain chlorine in the pool.

MPS will test as CC

From Pool School
Potassium Monopersulfate
A non chlorine oxidizer or 'shock'. It is acidic and will cause lower pH and TA. It adds sulfates to the water. Will not break down CC but helps prevent it from forming when used on a regular basis. It will interfere with TC and CC tests unless special reagents are used in testing since it WILL test as CC! A good choice to use in indoor pools that are not exposed to sunlight but really has no advantage in an outdoor pool. It is only an oxidizer and NOT a sanitizer and should not be used as such.
 
Getting ready to SLAM: How much chlorine to have on hand?

We're getting ready to SLAM and am trying to figure out how much chlorine (12%) to have on hand. Here are the test results from TF-100:
FC = 2 - 2.5
CC = 6.5
Alkalinity = 150 (down from 380+ when we opened the pool)
CYA = 35-40
pH = 7.2
Water is crystal clear and about 80 degrees

We had a problem with residual monopersulfate, but after running tests using the Taylor reactant, it looks like there is little/none left after almost a month.

So now we're ready to SLAM due to the high CC and I am very nervous that we get this right, knowing that if we don't get enough chlorine in the pool, we'll just be making the situation worse. Using the Pool Math calculator, in the FC fields, do I use the target shock FC (16 for CYA of 40) in the "Goal" field to calculate how much chlorine to use? Pool Math says 2.5 gallons, which seems to be too little considering the amount of CC we have. I've read elsewhere (not TFP) that the goal should be 10 x the CC, which would be 65 for our conditions. When plugged into Pool Math, it calculates we need 11 gallons of chlorine. In either case, I know that we'll need more than what is originally called for to keep the shock levels up until the CC< 0.5 and OCLT is <1.

To make sure we understand the process:
Do we add all the chlorine at once in the beginning, or should we start with 3/4 of what's called for?
Do we wait one hour between readings even in the first few hours of the process?

Many thanks for help.
 
Re: Getting ready to SLAM: How much chlorine to have on hand?

Based on your pool size and CYA of 40, that would be an FC SLAM level of 16. Poolmath calculator says that's 336 oz of 12% bleach. 446 oz if you were to use the standard 8.25% form the grocery store.

Start adding that chlorine ASAP to reach your SLAM level and simply make sure you KEEP IT THERE - so important. Check it frequently (about every hour) for the first day or so to see if your FC has been getting used-up. After a few days it should start to stabilize. Hope this helps. If you have any more questions, just ask.

- - - Updated - - -

Of course make sure you pass all 3 criteria:
1. Water is clear
2. You do not lose any more than 1ppm of FC overnight (that's the OCLT)
3. CC (Combined Chlorine) is <.5
** You MUST meet ALL 3 items above to properly do a SLAM. Simply “spiking" the FC higher than normal isn't SLAMming, therefore there’s a good chance your algae will return.
 

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Re: Getting ready to SLAM: How much chlorine to have on hand?

Thanks! This is a great help. We already have the clear water, so hopefully the other two criteria will fall into place. I guess the 2.5 gallons of chlorine seemed low as I had been adding 2 gallons a night and could only get the FC up to 3, but that was before we got the CYA up to 35-40.
 
Re: Getting ready to SLAM: How much chlorine to have on hand?

Dont bother adding 3/4. Add it all.
Wait at least a half hour between tests. If you plan on testing after just a half hour, then add the Chlorine and brush your pool really well. It will help mix it in.

You need to be brushing your pool very often anyways during a SLAM!

You can not test and add too often. As long as it is mixed in that is so you dont get a false test result.

It is ok to overshoot by a few numbers as well. This helps if you have to go to work or something. Raise it a little higher than shock level so it has some wiggle room.
 
Re: Getting ready to SLAM: How much chlorine to have on hand?

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Plug your numbers into poolmath, set your FC target to 16 and add what amount of bleach it says. You want violent action, a knockout punch. No lovetaps. This is a battle to death. An hour or so later, after you brushed it all and taken a breather to rest your aching back and shoulders and had a cold one, retest FC again, plug it into poolmath, and add again. Repeat.

You want to knock it down and then kick it again and again and again so it can't get back up and eventually it will all be dead. That's a SLAM.
 
Re: Getting ready to SLAM: How much chlorine to have on hand?

Got it. We're going to fix this! Just want to make sure we have enough chlorine on hand for what could be a long night. I'm thinking at least 20 gallons or more to begin with for the initial and anything that's needed tonight.
 
Re: Getting ready to SLAM: How much chlorine to have on hand?

I'm beginning to lose confidence: We've been SLAMMING for over 6 hours and have added about 25 gallons of 12% chlorine. We've had to add 3 - 4 gallons at a time so that we don't lose the little ground we have made. The highest FC we've registered is about 10, but the next reading (about 1.5 hrs later - had to run out to get more chlorine) was 5 ppm. But the CC must be through the roof as you can smell the typical chlorine smell. Should we just dump 10 gallons of chlorine in the pool or just keep up the 3 - 4 gallons at a time and hope for breakthrough sometime next week?:(
 
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Re: Getting ready to SLAM: How much chlorine to have on hand?

Add what poolmath says to get you back up to shock level. Sounds like there might be some ammonia in the pool. It uses a lot of chlorine in the beginning but clears up pretty fast. Keep SLAMing!
 
Re: Getting ready to SLAM: How much chlorine to have on hand?

I've been adding multiples of what Pool Math calculates (336 oz) and we're adding 4 gallon an hour! We did have high CYA (173) last year that disappeared over the winter: perhaps this caused the ammonia?
I'm concerned that we haven't been able to get to shock level (FC=16) yet after all these hours and chlorine.
So we should just keep on putting in this dose until we hit FC=16? and then maintain.
Thanks for your help, I'm getting desperate.
 
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Failure at Slamming?

We have been SLAMMING for the past 11 hours due to high CC. Here are the test results from TF-100 before we began the SLAM:
FC = 2 - 2.5
CC = 6.5
Alkalinity = 150 (down from 380+ when we opened the pool)
CYA = 35-40
pH = 7.2
Water is crystal clear and about 80 degrees, no chlorine smell.

We had a problem with residual monopersulfate, but after running tests using the Taylor reactant, it looks like there is little/none left after almost a month. Also, we had very high CYA last year (173) but it disappeared during the winter

We have been SLAMMING all night, testing and adding chlorine every hour. We have had to add 4 - 5 gallons of chlorine per hour, which is way beyond what is called for in Pool Math, just to keep the meager FC we have achieved. So far we have added about 36 gallons of 12% chlorine and am now down to using the 8.5% jugs of chlorine. We have not been able to achieve shock target of 16 at all. The hourly readings are generally about 6 ppm, and have two readings of 9 and 10, but these decrease to 6 or 7 at the next reading. However, the CC is off the charts. I gave up on the CC test when I had used 40 drops of reactant. The water has a very strong chlorine smell. To make matters worse, we discovered that there is now air in the water from return jets. Also notice that the last few times we added chlorine, the water turned 'smokey' for a minute or two.

What should we do? Should we add a huge dose (10 gallons) of chlorine to try to reach the shock level? I am concerned about the effects of so much chlorine on the pool itself. And morning is coming and the sun will be on the pool the whole day.

We really need some guidance here and appreciate any help.
 
Re: Failure at Slamming?

Good morning. I'm off to an early meeting so I won't be able to weigh back in for several hours but the questions I ask may help others understand and come up with ideas to assist you.

Before you started slamming, was your water holding the chlorine? Eg. How many ppm were you using a day? Or describe what was happening and how you were chlorinating and whether at that time you were testing with the TFP kit or are new to it.

- is tree any sign of organics at all any visible algae, cloudiness, slime, pink slime, back mold, etc..

- what all, in addition to the MPS, have you put in the pool this season or last?

- did you open yourself, and if so, did any RV antifreeze get into the pool water (its presently unknown, but at least three other posters have had cc/chlorine demand problems where they suspect this is related)

-- do you use a cover, and is that cover now off

-- have you had any fertilizer or pesticide spraying done on your property?

-- can you post a picture of your water

In the mean time, what happens if you leave it for a few hours..does it drop to zero, or stay at the albeit low 2 ppm you reported at the beginning?

Have you tested for ammonia? Normally, ammonia will immediately zero out the chlorine until its broken down but the consumption pattern is "acting" like ammonia.

The chlorine smell will be from the FC turning to cc, which does mean its fighting something. The question seems to be whether the something is organic in nature or chemical conflict.
 
Re: Failure at Slamming?

I would second fighting ammonia, is this the first SLAM of the year ( just opened the pool? ) or is this the second SLAM? With a CYA 170 down to 30/40 this year it looks like your fighting ammonia... once the fc starts holding your done fighting ammonia but fc will fall fast until its gone
 

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