FAS-DPD, Eh whats that? Again.

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Z

zephyrbar

0
Jun 15, 2014
25
Alta Verapaz
Hi everyone, I have been trying to find either a Taylor K-2006 or a TF-100 test kit where I live in Guatemala, all the pool companies seem to get their reagent kits through the same supplier in Guatemala, and they can only offer the Pentair Rainbow (ph and chlorine) Taylor K-2005 (with no FAS-dpd)

When the pool was opened by the contracted building company we were told that we would need to throw 1/2 cup of Trichlor in each day at sunset amd we would never have a problem, and that the majority of people that have problems have stopped using Trichlor and have started using bleach, pffft. After a month of this Trichlor, running the pump 24/7 brushing one day and vacuuming the next I noticed green algae near the entrance steps and a tinge to the water that is not getting better.

I have found bleach from our detergant supplier which is 10.5% which is a sight better that the normal 5.25% bleach which is the absolute best you can find in the supermarket, and at $1.60 a gallon it seems like good value. But, I have no way of pulling off the TFP method without being able to do the CYA and FAS-DBD tests, I can get a K-2005 kit but still can't SLAM the pool until I can find the right reagents, as far as I can understand.

I guess I am looking for any suggestions as to how you would go about this, I could buy they majority of the tests, the results of which you all need to give me a hand, but without the FAS-DPD I am stuck no? Any advice would be appreciated.

Chris.
 
:wave: Welcome to TFP!!!

You seem to have gained a good grasp of what we teach here :goodjob:

You are correct that without a FAS-DPD it will be more difficult, but you might be able to get by. I would suggest getting the K-2005, but you will also want to have the OTO chlorine test. The pink DPD chlorine test that comes with the K-2005 has a major draw back in that the color can fade out at high FC levels. At least with the OTO, the yellow just turns orange and then brown as you go to higher FC levels.

It is imperative that you can know your CYA level so you can know the required FC level for maintenance and SLAMing. For the FC levels, I am only suggesting this due to the inability to get the FAS-DPD and you must realize that you will not have the accuracy, you could use the OTO and do careful dilutions of the pool water with distilled water and multiply your readings to get a ballpark of the FC levels.

Another alternative, although likely not cheap, would be to use a 3rd person shipping company in the US to get the FAS-DPD mailed out to you. If you go this route, I would suggest stocking up a bit and storing it in a cool dark place.
 
Ok, so I have ordered the K-2005, I also have some friends coming into the country in a couple of weeks and I have asked them to bring a couple of TF-100s. Today the pool is much greener than yesterday and I can see a lot more Algae growth around the tiles, the pool is being vacuumed now as it was brushed yesterday! Triclor at the recommended dose is doing less than nothing it seems, I should have the kit in about 4 days but I am worried that it will become a green monster before that
.
The pool was opened for the first time by the builders on May 4th of this year, So...... can I assume that my CYA is low enough to begin a guesstimated dose of chlorine daily to at least stall the algae bloom? Thoughts welcome.

Chris
 
If you are able to buy refills for the K-2005, I am not sure you need a couple TF-100s as well. The reagents do have a finite life span. Have them just bring the stuff you can not buy locally ... like the FAS-DPD reagents that can be bought separately from the TF-100 and maybe some more CYA reagent.

trichlor tablets add FC too slowly. You could certainly start adding a couple bottles of bleach to the pool every evening.
 
It is not Trichlor tablets but the granulated stuff we have been told to sprinkle around the pool, is this any better at releasing FC? Should I just use the pool calculater and use a CYA of 40 as my guess, and calculate a min ppm of clorine from there?
Thanks for the advise I will just have them mule the reagents missing from the K-2005 then.

Chris
 
trichlor is slow to dissolve in any form ... and it is not good to let it sit on the pool floor as it is very acidic.

How much of the trichlor have you added? PoolMath can be used to estimate how much CYA you have added, although not sure what you started with.
 
Ha ha, ok maybe we can figure this out more or less.

May 4th Pool opened
May 9th/10th Pool opening party extravaganza
May 12th Pool completely drained to repair damage caused on 9th/10th
Pool builders, tilers and commissioning engineer back in over a 2 week period
May 25th Pool re-opened

I just got off the phone with the engineer, the pool was refilled with water from our only source, the river. The shock was done with 5.5 Lbs of Trichlor and 1 litre Floc, 1/2 gal algacide, pH up to 7.5.
Daily dose was 4oz of Trichlor granules a day, which I put up to 6oz 2 weeks ago when it started going cloudy, so a guess would be a total of 13.6 Lbs total in a pool of 33,000 Gal in rainy season so we have had some replacement of water too.

How would I calculate my CYA with that info using the pool calculator?

Chris
 
Enter the volume at the top and enter 13.6 pounds in the Effects of Adding Chemicals section.

Looks like that should have added about 27ppm of CYA at this point ... so you should not use trichlor for much longer.
 
Gotcha, just checked it too. Alright, so with that as a guessed start point could I start with a estimated CYA of 27 and dump in 10.5% bleach to the target FC of 4 and hold it as best as I can using my rainbow test kit, or is it worth going straight to shock FC of 12 and see saw my way through a SLAM as I wont have the FAS-DPD in my test kit anyway? Thanks for your help by the way.

Chris
 
Put enough bleach in to raise the FC to 12 because you need to get enough chlorine in the pool to kill the algae faster than it can reproduce. If you only add enough for 4 ppm then the algae will not be killed off faster than it can reproduce. You will stay somewhat ahead of the algae so the pool doesn't turn completely green until you get your test kit. Whenever you can measure the chlorine as being low raise it back up.
 

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Right, so it has been an hour since I put in the bleach, how long roughly until I can take a approximated clorine reading, as with the rainbow tester I have now, it reads 0.5, I know this kit doesn't give adequate info but can this be right? I was shooting for a 12ppm level and now it says I have 0.5, could it have been consumed already or should I wait longer and test again?

Edit-spelling
 
To follow up on Jasons question, OTO yellow color matching drop test will continue to turn, dark yellow, orange, etc off the top of the scale on the chart, but DPD pink color matching test will bleach out and read low at high FC levels

- - - Updated - - -

Assuming your test reagents are not old (keep in a cool dry place for maximum life) it looks like the chlorine you added has already been mostly consumed

also see http://www.troublefreepool.com/threads/58831-Extended-OTO-color-comparator
 
Ok just checked to make sure, it is the OTO1 chlorine/Bromine tester, reading < 0.5 I checked 10 mins after putting in the bleach and it was very yellow, now very pale, I was brushing the pool for the hour inbetween tests. Should I go ahead and dump more bleach in now, say another 3.6 gals?
 
So I added the bleach and then tested after a half hour and there was definately a higher amount of chlorine there. I diluted the pool test water 50:50 with purified water with a syringe and it tested above 3ppm with the OTO. When it drops I will throw more in but I am questioning how old the bleach is as would have expected to see a higher reading from the test after 30 mins.
 
Not only is the age of the bleach a concern, but so are its storage conditions, the warmer the storage the faster it looses strength, given typical availability concerns in locations like yours have you considered installing an SWG (saltwater chlorine generator)?
 

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