Low Chlorine Levels

I am experiencing low to no readings on my chlorine over the past few weeks. I have an AquaRite salt water chlorinator and my pool is approx 28k gal. I guess I'm just wondering if this is normal during this time of year. I'm here in sunny AZ and we will be up to 110 today. My pool has only been completed since last Aug and my chlorine readings have always been dead on 3.0 since then. During the winter I turned down the chlorine to about 50% and I turned the percentage back up to 90% a month or so ago but hasn't seemed to help much. I'm always having to add acid to keep my PH in line. Someone on the forum told me that was due to having a new pool and the curing process uses up a lot of acid. Anyway, just wondering if this is normal due to the extreme heat and if so how to supplement the lower readings. I added two bags of shock last night and my reading today is only about 1.5.

Thanks.

Brian

Brian, without a full set of chem numbers about all we can do is guess. There is a fair chance that your cya is too low to protect the generated chlorine from burning off in that Az sun.
Please post some test #s and we'll offer some suggestions:)

I don't have a very good test kit. What are the readings that you need to see?

Brian, what I was looking for are :
Free Chlorine
Combined Chlorine and/ or Total Chlorine
pH
Total alkalinity
Calcium Hardness
Cyanuric Acid
- this will tell us about the condition of the water

However, as you have the AquaRite unit, will you please open the door to the unit and press the diagnostic button (located to the left of the LED display) 5 times, and post what the display says after each press? - this will tell us the condition of the unit/ cell.

Thanks for doing this and helping us help you :)

I'm guessing your stabilizer is low. My SWG runs at 40% which is the standard setting.

OK here are my numbers:

Free Chlorine 2.0
Combined Chlorine 2.0
Total Chlorine 0
pH 7.8
Total alkalinity 110
Calcium Hardness 400
Cyanuric Acid 60


Keep in mind I got to these numbers by adding over the past few days 1 gallon of pool acid and 3 lbs of shock.

Thanks.

are you sure you didn't transpose your combined Chlorine and your Total Chlorine numbers? With a CYA of 60 youo should be in the sweet zone for your SWG to create lots of Chlorine. Did you try and test the water at the one of the returns when the SWG is on, you should get a high chlorine reading from there. Maybe you should check your salt level.

As I mentioned before I don't have a very good test kit so I took my water to the pool store. The guy who tested it said my FC was 2.0 and Combined Chlorine was 2.0 so he said that would make my Total Chlorine 0. Is that correct? I didn't take the water sample near any return and the pump wasn't on. I'm going to test my chlorine again in the AM to see what it reads.

Quote:

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Originally Posted by BigButz

As I mentioned before I don't have a very good test kit so I took my water to the pool store. The guy who tested it said my FC was 2.0 and Combined Chlorine was 2.0 so he said that would make my Total Chlorine 0. Is that correct? I didn't take the water sample near any return and the pump wasn't on. I'm going to test my chlorine again in the AM to see what it reads.

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Nope. Simple rule forever and ever: Total Chlorine = Free Chlorine + Combined Chlorine.

If they don't add up the test is faulty.

The BEST investment you can make in pool care is a good test kit.

Some WalMarts have an HTC 5-way drop test kit for about $10- $15. It's pretty good and the best value in test kits. It has some limits but it's still pretty darn good.

But better by far is an FAS-DPD test kit. Chlorine tests fall into 4 types: Strips, OTO, DPD and FAS-DPD. You can buy strips, OTO and DPD at most pool stores, but you'll need to go on-line to get an FAS-DPD test kit. It's worth every nickel.

There are two best places to get a kit.
You can go to taylortechnologies.com and order their K-2006 or K-2006C test kit

or you can go to Leslies On-Line and order their FAS-DPD Chlorine Service Test kit.

Plan to spend between $60 and $75 on a kit (but the 2006-C is a lot--about $125 because you get a lot more of each chemical)

Now, Assuming your FC and TC are 2.0 and your CC is 0, but your CYA is 60, you should keep FC between 5.0 and 10.0 at all times or you will get algae.

If you have algae, you need to shock it up to 20ppm and keep it there until you are clear.

Another pool site sell a proprietary kit that looks similar to these that you can investigate.

I'd stay away from Calcium based chlorine as your Calcium level is at the top of the good range. I'd stay away from Tri-Chlor pucks and Di-Chlor as your CYA is getting high.

Your pH is a tad high at 7.8 but still acceptable. However, if you are fighting algae, lowering it to 7.3 to 7.5 will help the fight.

So you should only chlorinate with bleach/liquid chlorine, or your SWG.