What To Adjust First, Chlorine Or Alkalinity?

by Tom Peris
(Hercules, CA)

I have a 15000 gallon pool. My salt water chlorinator is not producing chlorine. Is this becuase my pH is so low?


When I tested the alkalinity, the result was 230. Do I adjust the alk. or first or do I have a problem with the system producing chlorine.

Thanks.




Thanks for the question Tom

There could be a few reaons why the salt cell insn't producing chlorine. First is the obvious... low salt. Have you had your cell calibrated correctly? Do you know if it's reading the right salt level? I used a Myron Analog Salinity Meter and it's great to have on hand:

Salt Water Swimming Pools

Check the stabilizer level in the pool. It should be between 30 - 50ppm. It's it too high, above 70 - 80ppm, or too low, below 20ppm, the chlorine will not be active.

The settings on the control box are correct.

Check the cell for build-up of debris or calcium. Clean it with a mixture of 4 parts water to 1 acid.

I'd like to have the reast of your chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Calcium Hardness, and Metals (iron and copper).
It makes troubleshooting much easier and the process will go much faster. You can get this done at your local pool store.

The high alkalinity can also chew up the chemicals. Your TA is 230ppm. Normaly range is between 80 - 100ppm, 120ppm being the top. You need to decrease the TA by 130ppm.

It's 0.8 qrts. of acid to lower TA 10ppm per 10,000 gallons. Add in one spot in the deep end with the pump off for 3 - 4 hours. Gently sweep to break up any hot spots of acid. Pump back on and FILTER for 8 - 10 hours, retest, and make another adjustment.

Concerning the pH, it's hard to say what "low" means. However, a salt cell can cause the pH to decrease so that is something you need to keep an eye on.

Get the alkalinity in line and you may need to manually dose your pool with chlorine until you find out why the salt cell is not producing.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Alkalinity" category.

Check back to this post for updates or answers.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of your choice and I'll answer your questions by phone.

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Hope this helps and have a great Summer.

Robert

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Alkalinity Won't Stay Above 50

by Shannon
(Sandpoint, ID)

We can't seem to get our total alkalinity to stay above 50; In ground, outdoor spas.

We add sodium bicarbonate to raise alkalinity; pH goes up and acid feeder kicks in;

Using calcium hypochlorite (Pulsar Plus) with feeder.

So we end up using a lot of soda and a lot of muriatic acid.

Thanks




Thanks for the question Shannon

In know how difficult it is to get the TA to stay in range while the pH goes through the roof. The fill water at the Y were I was the pool operator was 8.0 pH and 30ppm TA. When bicarb is added both go up, then muriatic acid to lower pH and both go down.

This is the yo-yo effect and it can be frustrating.

You're actually triple raising the pH, and here's why. First, you're using calcium hypo. This kind of chlorine already has a pH of 12. When added to the spa it will increase the pH. I'd encourage you to switch to either liquid chlorine, bleach, or bromine. Bleach is nothing more than watered down pool chlorine, sodium hypochlorite. Chlorine is 15% sodium hypo and bleach is 6%.

Clorox bleach
"http://www.clorox.com/products/clorox-regular-bleach/ingredients-and-safety/"

Click on the sodium hypo button

Pool chlorine
"http://www.conelyco.com/Pool-Spa/tchlor.pdf"

Section II Hazardous Materials box

2nd is you're using bicarb which you already know will increase the pH.

And 3rd is when you turn on the jets you're creating alot of bubbles. This increase the pH naturally because the CO2 (carbon dioxide) is being burned off.

Here's what I would do to increase the TA in the YMCA's hot tub. Turn off the system and add the bicarb to one spot, allow it to sit for 2 - 3 hours, then turn the system back on FILTER with NO jets.

After one complete turnover of the water, normally about 30 - 40 minutes per 500 gallons, retest the water and make another adjustment if needed using the same technique.

It's 2.5 oz. of bicarb per 500 gallons to raise the TA 10ppm.

Pool Alkalinity

Total Alkalinity

You may need to repeat this process a few times until you get the proper range of 80 - 100ppm TA. It will be harder to hit this mark if you try to get the pH down to 7.2 - 7.4 so I'd suggest a pH range of 7.6 - 7.8.

This is one area that is unlike a pool. You're dealing with a smaller body of water and making adjustments will be more frequent.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Alkalinity" category.

Check back to this post for updates or answers.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of your choice and I'll answer your questions by phone.

Contact Me

Donation

Hope this helps and have a great Summer.

Robert

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Alkalinity Slightly High

by Jamie

Perfectly clear pool water oh is perfect 7.2-7.6 but alkalinity register 140 every time I tested the water?? I do have the Taylor test kit but it is a simpler model with less vials. Should I still try and decrease the alkalinity or is it ok at 140. We have a plaster 30000 gallon pool.

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