Chemical Balance or Possible Algae?

indycreed

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Jun 21, 2010
17
I have just recently switched to the BBB method. My water is beautiful - crystal clear. I live in central Indiana. We have had tons of rain and hot weather so far this season.

I have been testing with the k-2006 religiously. I know my TA is on the high side. I'm planning on using the advice on this forum to lower it.

Despite my beautiful water, I have been losing chlorine (never below 2.0) like crazy. I did the overnight test last night and went from 30.0 to 16.0 FC. I know that having high TA can affect chlorine efficiency, but can it cause FC to drop that much in such a short period of time? Or, am I fighting algae?

FC - 16.0
CC - .5
pH - 7.3
TA - 160
CH - 200
CYA - 80
 

duraleigh

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Apr 1, 2007
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Good morning and welcome to the forum. You have algae (even though you cannot see it).

Two things consume chlorine.....1) sunlight and 2) organics (algae included) in your pool.

It looks like you started the shock process yesterday. The best thing you can do right now is to bring your FC right back up to around 25 or so and KEEP IT UP THERE until the overnight loss gets down to 1ppm or less.

read "How to Shock Your Pool" up in Pool School.

How are you chlorinating the pool?
 

JasonLion

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May 7, 2007
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Welcome to TFP!

What duraleigh said. An overnight loss like that means algae, or some related organic problem. You need to continue shocking until the overnight loss is 1.0 or less.

TA levels don't have any direct effect on chlorine consumption.
 

duraleigh

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Using bleach, I would suggest allowing your CYA to eventually lower down to around 50ppm. You could also do a partial drain to get it done immediately if you choose.

That would allow your FC levels to be lowered by a significant amount and still provide the protection you need against algae blooms.
 

indycreed

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Jun 21, 2010
17
My goal is to get the cya down to 50 as soon as I get this taken care of.

Is the pool okay to swim in while I'm shocking?
 

duraleigh

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Yes. Shock value (from the FC/CYA chart) is a guideline that we use for safe swimming. It's possibly much higher but shock value is an easy guide for all of us to remember.
 

indycreed

Member
Jun 21, 2010
17
No particular reason - just tackling one giant at a time. Since it takes so long to refill the pool after a partial drain, I thought I would get on the algae since it seems more concerning. I have plenty of bleach on hand at the moment.
 

poolgirl22

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Apr 14, 2010
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Stephens City, VA
Indy-
Not sure what your situation is up there but I know here it takes awhile to refill as well. The water dept has flow valves on the meters to more evenly disperse the pressure...so I've often considered asking the neighbor if I could run a hose from their place to ours, then paying the portion of the water bill that month beyond their normal usage. It's an option.

You'll really use less product to shock if you lower the CYA and refill. Even if you only do it 15 or 20% at at time. I'm so thrilled mines down from 55 to 45 since season beginning. All that rain we've had and wasting of water paid off a bit.

Good luck!
 

chem geek

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Mar 28, 2007
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Do you happen to know the lowest Free Chlorine (FC) level that occurred before you started to see this unusually high chlorine demand? Was your Cyanuric Acid (CYA) level 80 ppm at that time as it is now?
 

indycreed

Member
Jun 21, 2010
17
To be honest, I'm not sure what the levels were because I was having the pool company testing my water. I just got my k-2006 about a week and a half ago.
 

indycreed

Member
Jun 21, 2010
17
I think I am almost there with beating the algae (knock on wood). I only lost 5ppm FC overnight and my CC is now 0.

One question - my TA has gone up to 200. Will this come down as the chlorine dissipates? I added some Ph down this morning. It brought the Ph down, but not the TA. That's why I wondered about the high level of FC having an effect on TA.