Start SLAMing without Chlorine FAS/DPD test (my experiences--YMMV)!

[calinb]

It seems to me that the FAS/DPD test precision and accuracy is only absolutely necessary to determine when to end a SLAM (perform the overnight FC loss test, aka "OCLT"). However, while waiting for deliver of your FAS/DPD test kit, a simple OTO "yellow" test and an "overkill" use of LC can get your SLAM started. At least it did for me.

My wife and I recently bought an old homestead with a pool that had been closed at the end of summer four years ago. When I uncovered the pool and began the pool opening process, I was met by a swamp, plumbing leaks, and a faulty 220V line to the pump (a short in the underground conduit ). After two or three days waiting on the electrical to run the pump, I had the pool bottom almost free of coarse debris, but by then an algae bloom was in full swing. I clearly could not wait for the arrival of the TF-100 test kit I'd ordered to get started so I SLAMmED the pool without it and kept SLAMming until the test kit arrived.

According to the last commercial pool maintenance company log summary of four years ago (shortly before the pool was last closed), the CYA reading was 30 ppm, so I targeted 12 ppm for FC, per the SLAM guidelines. After a few days, I found that the sun of the day nearly zeroed out the pool TC, whereas little very little FC was lost at night so I began to suspect that the CYA was much lower than the last test result (which was confirmed later by my TF-100 kit and a reading well under the 20 ppm lower limit of the kit).

While waiting for the kit, I got pretty good at "cheating" without a DPD kit by matching the first OTO test yellow hue quickly with a kit that came with the pool. In order to extend the range of the OTO test to 15 ppm, I used a simple method. Before testing, I filled a beaker with four industrial syringes worth of our well water (very soft and obviously no CL) and then added one syringe full from the pool, mixed the water and filled the OTO test kit cylinder from the beaker. Then I multiplied the OTO test result by 5 to compensate for the diluted sample.

In one week's time, I went through 35 gallons of LC (25 Wally World 6% jugs and 5 Kmart KemTek 10% jugs). By the time my TF-100 kit arrived with the XL option, I didn't need the extra FAS-DPD reagents in the XL option. On the first night, the pool passed the FAS-DPD OCLT and I ended the SLAM!

So based on my experience, one doesn't need the excellent TF-100 kit to get started with a swamp cleanup, but the kit's precision is certainly necessary to determine when to end the SLAM. Just my $0.02 here, of course.

 

[woodyp]

As much as I'm tickled that worked out for you, the fas-dpd test is essential in the MAINTAIN part of the SLAM equation.

 

[calinb]

Can you please explain to me how my method fails to maintain the target FC within an entirely adequate range of uncertainty? Granted, an FC reading using OTO requires one to quickly assess and match the color, but I tested my method against the TF-100 FAS-DPD test a couple of times, just for kicks and I'm pretty quick with it (I have lots of FAS-DPD reagents to spare with the XL option), and the correlation was very good (within the 5x multiplier uncertainty "spread" introduced by the sample dilution).

The problem with my method is the precision is not sufficient to detect a CC (TC-FC) of 0.5ppm or less for the OCLT, but it can certainly measure FC within the 12 to 15 ppm range that I needed (and it turns out I only needed 10 ppm, because my CYA turned out to be very, very low--immeasurably low and perhaps zero). The only downside for me was I probably spent more money on chlorine than I would have spent, had a TF-100 test kit been available in less than a week+ in shipping. (I probably could have ended my SLAM earlier, with a TF-100 kit in hand.) My CYA turned out to be much lower than expected, but the somewhat higher than normal FC SLAM target level burned off in a day's sun anyway.

I can't even imagine how much worse my algae bloom would've been after an additional week waiting for the TF-100 arrival!

 

[duraleigh]

I am also glad that worked for you. I am gonna' pull the "experience" card and tell you that after 12 years on the forum, VERY few folks can do what you have done.

Most need more precision and black and white rules. Glad it worked for you but if you are suggesting we can alter the methods we teach, that is incorrect.

The TF-100 or K2006C go hand in hand with the methods we use. I am happy that you don't seem to need them but most folks certainly do.

 

[jblizzle]

We would never recommend this method due to the great potential for inaccurate results depending on how well someone can measure correct dilutions. Some members struggle enough just multiplying 0.5 for the drop count

 

[Poolzzz]

Can you please explain to me how my method fails to maintain the target FC within an entirely adequate range of uncertainty?

Well, as you showed, you had no idea the cya level and got it quite wrong. So you used much too high a FC level which risks damaging pool and equipment.

Secondly dilution multiplies the uncertainty. The uncertainty with an OTO test is barely adequate to begin with so 5x barely adequate is not going to give you an "entirely adequate range of uncertainty".

Dilution is certainly possible. But once you are doing 5x I suspect you would be better off just putting in a fixed amount each day (morning and evening) until the proper test kit arrives. It's certainly less work, probably just as effective, and likely safer.

 

[calinb]

Well, as you showed, you had no idea the cya level and got it quite wrong. So you used much too high a FC level which risks damaging pool and equipment.

I had no economical way to increase my CYA significantly without placing another mail order, because the only stabilizer was an hour away at a pool store and overpriced. Had I waited for my TF-100 test kit CYA result, it would have been 2 weeks of algae bloom! As it turned out, either the commercial pool service company's test summary was totally wrong about the CYA four years ago (a common occurrence as reported in this forum) or four cold Idaho winters zeroed out the 30 ppm CYA or ??? No one seems to know why CYA is reported to disappear sometimes.

According to this table, I was still very close to the recommendations for yellow/mustard algae so I doubt there was much risk of damage.
http://www.troublefreepool.com/threads/2177-Chlorine-CYA-Chart

Secondly dilution multiplies the uncertainty. The uncertainty with an OTO test is barely adequate to begin with so 5x barely adequate is not going to give you an "entirely adequate range of uncertainty".

I covered the uncertainty issue. Because the precision in viewing and grading the yellow "graduations" is perhaps 0.5, it makes sense to err on the high side by 5 x 0.5 = 2.5 ppm. Thus my FC=12 target becomes 14.5. I usually just rounded up to 15 and looked for a 3.0 (5 x 3.0 = 15) on the scale or a shade very nearly 3.0..

Dilution is certainly possible. But once you are doing 5x I suspect you would be better off just putting in a fixed amount each day (morning and evening) until the proper test kit arrives. It's certainly less work, probably just as effective, and likely safer.

Testing wasn't much work, but removing bottom sludge and algae (brush, brush, brush) certainly was! I felt like I was already behind the curve, given the delay in getting my pump online to produce circulation in the pool.

 

[calinb]

I am also glad that worked for you. I am gonna' pull the "experience" card and tell you that after 12 years on the forum, VERY few folks can do what you have done.

Most need more precision and black and white rules. Glad it worked for you but if you are suggesting we can alter the methods we teach, that is incorrect.

The TF-100 or K2006C go hand in hand with the methods we use. I am happy that you don't seem to need them but most folks certainly do.

I'd never suggest that you alter your advised methods, which appear to be very sound and sensible to me and furthermore, I agree that my TF-100 kit was needed to know (not guess) when it was safe to end the SLAM. Also, it's a wonderful kit and the methods are very well designed and explained in the instructions. My approach fell into the category of "desperate times require desperate measures!"

You are probably also right to pull the experience card, Dave. I'm pretty good at quantitative research and experiment and measurement methods. My first degree was a B.S. in Physical Sciences with plenty of chemistry and chem lab in the curriculum. I took chemistry courses up through organic chemistry and physical chemistry, including quantum mechanics. I never used it much though, because I moved on to grad school in Electrical Engineering. I've also had several tropical fish aquariums for many years, and that hobby is chock full of pool-like test methods too!

 

[Wulfdan]

I applaud your resourcefulness.

I personally wouldn’t recommend it, but I understand why you chose to move forward with what you had.

 

[calinb]

We would never recommend this method due to the great potential for inaccurate results depending on how well someone can measure correct dilutions. Some members struggle enough just multiplying 0.5 for the drop count

No doubt sound testimony, Jason. Hence my note: "my experiences--YMMV" in the subject line.

 

[zea3]

calinb I'm glad you were able to clear your pool. You had the good fortune of a pool low in CYA to start. After 4 years of rain dilution and natural deterioration you were probably close to 0. For our members that have high CYA numbers guessing to hit their slam levels wouldn't be practical, and we have found actually prolongs the slam process. Since most people will not have an accurate CYA result until their test comes in, they won't know if they should have been draining the pool instead of starting the slam. If you add 20 gallons of bleach while waiting on the kit only to find you need to drain half the pool thats a good chunk of money and time down the drain. Adding bleach until the kit arrives can keep the status quo or in some cases give a head start. Keeping the FC in correct ratio to CYA is critical.

 

[cfherrman]

If you can't get a kit then you gotta do what ya gotta do, if you can can get one then it is not very smart risking damages or risk wasting money by not using enough or too much clorine, or just running in circles.

 

[Flying Tivo]

My kind of thinking, do the most with what you have! Congratulations!

 

[calinb]

calinb I'm glad you were able to clear your pool. You had the good fortune of a pool low in CYA to start. After 4 years of rain dilution and natural deterioration you were probably close to 0. For our members that have high CYA numbers guessing to hit their slam levels wouldn't be practical, and we have found actually prolongs the slam process. Since most people will not have an accurate CYA result until their test comes in, they won't know if they should have been draining the pool instead of starting the slam. If you add 20 gallons of bleach while waiting on the kit only to find you need to drain half the pool thats a good chunk of money and time down the drain.

Very true! I highly suspected my CYA would test low, given the 30 ppm report of four years ago. I'm still don't know where most of that 30 ppm CYA went (if it ever was 30 as reported), however. The pool cover was rain proof and kept nearly all water from entering the pool, though it badly failed this summer and that's why I dug into it now, despite having many other projects to tend-to around this old Idaho homestead. It's been hot and dry and I needed to clean it up before the high winds and rains come.

I thought about adding a smaller amount of LC to it while I waited for my TF-100 kit to arrive, but that would not be a SLAM-prescribed dosage and method either and I was unsure how much to add and whether it would be a waste of LC too (though a smaller waste than having to drain most of a pool later, because of high CYA). Again, I was pretty sure my CYA would test low and it's a very good thing that I didn't have to drain water. On a 0.8 gpm spring with a 2600 gal. cistern, I would need water tanker trucks to fill it. According to the pool logs, the last time this 17,500 gal. pool was drained was in 1999 for an acid wash and it took 11 tanker truck loads of water!

 

[Pv2]

I'm curious what the recommendation would be in a case like this? Just wait until a kit arrives (cover it back up?) Some minimum dose of chlorine until it arrives, while trying to at least get the solids out? What would the minimum be?

I am thinking work to get the gunk off the bottom and a slam dose equivalent to 0 CYA should be safe? If one got the color change from green to bluish, wouldn't that be a sign they were on the right track and could at least maintain that amount daily? (of course no change would probably mean there was a significant amount of CYA, not sure it would be worth doing more until proper testing in that case or would some amount of daily chlorine be better than none?)

 

[jblizzle]

While waiting for the test kit, we typically recommend working on removing any solids and adding "a bottle of bleach" each day {amount kind of depends on the pool size}. This generally would keep the pool from getting too much worse.

calinb, with the last known CYA test being 4 years old, there is no way anyone could guess the current level. If you would not using any trichlor or dichlor, then I would assume the CYA was near 0.

 

[calinb]

calinb, with the last known CYA test being 4 years old, there is no way anyone could guess the current level. If you would not using any trichlor or dichlor, then I would assume the CYA was near 0.

Nothing was added to the pool during the four years. The owner had moved away. The owner used trichlor in the past and I need to dispose of about 50 pounds of the "plus" tabs ("free to good home" in the nickel ads?). The previous owner also used Cal Hypo, which I'll keep because my CH is currently low.

 

[JoyfulNoise]

Thanks for the post.

Your CYA was very likely zero. There’s no mystery to where CYA goes - it oxidizes from exposure to chlorine at a rate of about 5-10ppm per month depending on water temperature and UV exposure. During the hot months in the desert here, I’ve lost as much as 20ppm in a month. The second route is biological - there are algae and bacteria that can use CYA as a source of energy. CYA is consumed and converted to ammonia and then, if you are lucky, a different set of bacteria will convert the ammonia to nitrates and nitrogen gas. TFP gets plenty reports every year of winterized pools that are opened only to have a huge FC demand caused by ammonia formation. Once that happens, it’s often easier and cheaper to simply drain as much of the pool as possible, refill and SLAM.

In your case, your blind SLAM went quickly because you had no CYA. Therefore your active chlorine levels (HOCl/OCl-) were, as TFP would describe them, ASTRONOMICALLY high. Thus the CT-kill rates of biological pathogens and oxidation rates of organic matter were off the charts high. This is not dissimilar to how pool service companies will often clear a swimming pool - they lower the pH to below 6.8 and then raise FC to 50-100ppm. There is so much chlorine in the water that nothing can survive and the green water almost instantly turns grey. They let that sit for a couple of hours and then return later in the day to add flocculant to the water to drop the suspended solids to the bottom. They come back the next day to vacuum to waste and then adjust the pH back up with soda ash while usually telling the customer to wait a few days before swimming as the FC can be too high. They don’t care much to measure CC’s or see if their overnight loss rate indicates a job well done - the service industry mostly assumes that clear water is indication of clean water. Not true, but that’s how they operate.

The cautionary tale above and in your own experience is that not knowing where your FC is relative to CYA can be very dangerous to pool surfaces and equipment. You can easily wreck a liner and bleach it out if the FC is too high. OTO test kits are useless - they are highly inaccurate and one can easily prove it to themselves by doing the tests side by side. I found an OTO tester I had would report a yellow color in the 4-5ppm range when my DPD kit would show it to be barely 1.5ppm FC. SO while OTO will tell you that chlorine is present, that’s as far as it goes for a test. Titration with a DPD-FAS kit is the only way to get remotely accurate FC/CC numbers and TFP’s primary philosophy is to only add to your pool what it exactly needs...you can’t know what to add if you can’t test it.

Good luck to you with your home and pool, sounds like you guys live in a nice far off location with a lot of peace and quiet.

 

[Pwareing]

Well done working through the problem - a very similar story to mine but I have no recommended test kit because they cannot ship to France. The distributors charge above top dollar prices so I ended up with a basic HTH test kit to nail down my CYA then bleached away using dilution testing from there.
One point I struggle with is if HTH can ship a test kit why can't Taylor or TF????? I know the chemical arguments but HTH told me they use Taylor reagents so whats the difference - or is it a marketing strategy to promote a certain distributor?
Felicitations a tous a TFP
Peter

 

[JoyfulNoise]

TF Testkits is a small, US based company. Within the USA, there are specific shipping laws that limit the shipment of chemicals and liquids to ground-based transportation methods. In many instances, some private shippers like UPS won’t even touch chemicals. When dealing with foreign shipments, there are export laws involved that must be followed with limits on what can be shipped outside the US by our government as well as import restrictions on what can be brought into a country (the EU controls import restrictions for France). The entire process can be complex and expensive and may require surface transportation (shipping). It would basically be cost-prohibitive.

Large corporation often have subsidiaries and/or offices in foreign countries and that can make shipping a lot less cumbersome and expensive.