Algae is Beginning to Fade!!!

Jun 6, 2007
16
Alabama
With a lot of POP and some encouragement from you guys I am starting to come on the other side of this algae problem. The water is starting to clear and I only have about a 1' "layer" of greenish hue water in the deep end that is clearing now. I think the biggest problem I was experiencing was that I started from a leafy swamp and the cc's in the water were staying too high to let the chlorine do its job. This week we have had a good bit of sunlight to help with the process and it has really turned things around.
I also had a little bit of trouble with the PH dropping too low. This was probably due to dosing the pool with muriatic acid while also allowing my cya granules to dissipate in a knee high in the skimmer simultaneaously. I figure the cya was lowering the ph as well as the muriatic. Getting the ph back up to speed seemed to move things along as well.
The question I would like to pose now pertains to cc.

When testing your water (OTO) while treating for severe algae and unseen organics due to water clarity would the cc be showing up in the test sample? Or for that matter would during routine testing would some of the reading you are getting in the color shade be cc's as well?

In other words, if I take a water sample during an algae outbreak and it consistently reads a chlorine level that is say 3-5 would some or most of that ppm cl be tied up in cc? I know that during one 5 day period I would keep seeing chlorine levels at or above 5 even though I had added no additional chlorine and the water was still green. I have come to the conclusion that if you are trying to fight algae and you don't have a FAS-DPD test you will have a fight on your hands. Especially if you are impatient.

Thanks for the help and encouragement it looks like I am only a couple more shocks towards winning this battle. When this is over with I think I will test for metals because the trim strip around my steps is looking rust brown.
 

JasonLion

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May 7, 2007
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Silver Spring, MD
Congratulations!

The standard OTO chlorine test, add drops to turn various shades of yellow compared against a color standard, measures TC (total chlorine) which is the sum of FC (free chlorine) and CC (combined chlorine). During normal operation one generally assumes that CC is near zero and so takes the TC reading as a proxy for FC, ie just assume that the test is showing FC. However, when fighting algae the CC level will be significant and the OTO test isn't very useful. This is one of the reasons I recommend the FAS-DPD test. It will reliably distinguish between FC and CC.

Now it is possible to get an estimate of FC vs CC with the OTO test. The initial color of the sample will show FC and after several seconds the color will shift to showing TC. If you are fast and good at distinguishing shades of yellow you can get some idea of FC and CC (CC = TC - FC). However the transition is not usually very sharp and most people have trouble getting a solid estimate of the shade of yellow before it starts shifting.
 
Jun 6, 2007
16
Alabama
The problem with me is I must be somewhat yellow color-blind because I have a very hard time distinguishing the yellows on that test at any time during the whole process. I have to resort to asking the wife and kids what they think matches. It is very annoying.
 

duraleigh

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Apr 1, 2007
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I have come to the conclusion that if you are trying to fight algae and you don't have a FAS-DPD test you will have a fight on your hands. Especially if you are impatient.
True words. I would say that clearing a pool quickly is a daunting task without FAS/DPD tests. It can be done, but it's a shot in the dark with a lot of guessing.......especially if you are at all inexperienced.
 

Butterfly

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May 30, 2007
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chemistrydropout said:
The problem with me is I must be somewhat yellow color-blind because I have a very hard time distinguishing the yellows on that test at any time during the whole process. I have to resort to asking the wife and kids what they think matches. It is very annoying.
You are not the only one with that problem. During swim season I use the FAS/DPD tests almost daily. Uses up the 'stuff' faster, but I have NO DOUBT about the test results and that is a great feeling. :-D

Wait, did you hear something?....... I think I heard Dave (duraleigh) counting his millions $$$$! JK :wink:


Joyce
 
Jun 6, 2007
16
Alabama
AND

duraleigh said:
I have come to the conclusion that if you are trying to fight algae and you don't have a FAS-DPD test you will have a fight on your hands. Especially if you are impatient.
True words. I would say that clearing a pool quickly is a daunting task without FAS/DPD tests. It can be done, but it's a shot in the dark with a lot of guessing.......especially if you are at all inexperienced.
To add to the problem I tested 2 different times for cya and it was non-existent or below 20 ppm anyway. That puts you having to deal with acceptable chlorine levels to keep from having to damage things due to high concentrations of non-stabilized chlorine. To some this would be a blessing because it would lower the amount of chlorine needed to shock but when things are not improving you are worried that shocking a little higher can cause fading and such.