Can't hold chlorine level

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C

cabber

0
Mar 28, 2007
17
I've had my pool for a few months and really struggling with the Chlorine levels. I have the Jandy Aquapure SWG and it appears to be producing chlorine fine as I check water from the returns and there is plenty of chlorine showing in the test. All other test are in acceptable ranges.

TC - 1.0
CC- 0.0
PH - 7.4
TA - 90
CYA - 80

Right now I run my pump for 12 hours per day as the heat is here in Texas. The only way I can keep my Chlorine levels at 1.0 is to run the SWG at 100percent. That, I know, is not normal.

My neighbor has the same equipment, and keeps theirs at 65 percent and all is well.

One area I have not explored is shocking the pool. I know this has never been done. Not even on start up. Would shocking help stabilize my chlorine depletion? Any help would be appreciated. Thanks.
 
You should take a look at the cell and see if there are any signs of scaling (calcium on the cell plates). Scaling could reduce the chlorine production rate such that you are getting chlorine, just not enough to keep up.

Algae in the water is another possibility. A SWG often has problems fighting off algae once the algae has gotten started. It is possible for the SWG to be almost keeping up with the algae so the water is still clear. You could test for this by bringing the FC level up a bit in the evening with bleach, turning the cell off, and then checking to see if the FC level drops overnight.
 
Assuming your cell is clean shocking the pool with bleach would be a cheap way to find out.

It costs $7 to shock my 21,200 gal pool, but my CYA is lower than yours. I don't know what you need to reach break point in a SWG pool since your CYA is higher and your FC residual is lower, as it should be.
 
Thanks for the replies guys. Like you, I thought the cell was the issue as well, or potentially a faulty board in the control panel. Not the case on either as I had the builder replace both about a week ago. I was convinced it was the issue, but still having the same symptoms with the new cell and board.

I've had bleach in a several occasions. When I back the output on the SWG down to 65% after one full day my chlorine is all but gone so I have poured a couple of gallons of bleach in before. It doesn't last long though.

My cacium hardness is at 200

My pool is 22500 gallons with pebble finish. As I mentioned, the pump runs 12 hours per day with chlorine output set to 100 on the SWG. I just checked the Chlorine levels and it is barely at 1. When I check the water coming directly out of the return it shows a 4-5 PPM level.
 
So the new pool season is near and I'm back at the "can't keep chlorine levels" issues once again. After a year of testing-observing, I am still baffled at the lack of chlorine my SWG produces.

The pool is one year old and I have not had one week of consistent 3.0 Chlorine. AS I mentioned I have the Jandy Aquapure 1400 SWG. The board has been replaced, the cell has been replaced, I've had the pool people out here testing the water, and on and on.

Help me understand because maybe my expectations are somewhat misguided. My pool water temp from September-November, on average, was 70-73 degrees. I ran the pump for 10 hours per day during this time with the SWG output on 75%. We did not swim in the water one time. My pool water testing showed consistent results to the numbers in the above post. At this output level for the SWG, no activity in the pool, and water testing results showing nothing out of the ordinary, wouldn't one conclude that the amount of chlorine in the pool should be able to sustain 3.0-5.0...if not higher readings?

I'm headed to Leslies to get accurate water readings and will post them shortly. I've had my pump running for the past 24 hours, water temp is 60 F.
 
Just to review: The most common problem with this symptom is low CYA level. Second is low levels of algae that can't be seen but which consume chlorine. Another would be cell plates covered with calcium. Then you get into more obscure things like SWG broken, plumbing issues that reduce flow through the SWG cell, extremely high levels of phosphates, other rare and unusual water contaminates, and so on.

I see that you have been testing the CYA level. Have you tried shocking to rule out low levels of algae?
 

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If all other factors, such as the ones Jason mentioned, have been exhausted, then one can test the phosphates level to see if it is extraordinarily high (> 3000 ppb). If so, then it will take higher chlorine levels to keep up with preventing algae growth and would need a strong shock to knock out the algae first and then higher FC levels to keep it at bay. In the rare case where the phosphate levels are very, very high and you can't or don't want to maintain very high FC levels, then a phosphate remover (which is expensive) would be an option, but this is the LAST thing to look at -- check the much more common factors out first such as CYA level, salt level, plate scaling, etc.

Richard
 
Just got back from Leslie's and they gave me an "A+" grade on my water:

Results look like this:
FC: 3
pH: 7.6
TA: 100
Calcium Hardness: 230
CYA: 50
Phosphates:100
Salt: 2800

Keep in mind this water sample comes after running the pump a solid 24hrs. with the SWG set to 85% output. The only thing I can conclude from this is I need to keep the output of the SWG higher and run the filter longer. I've been down the phosphate path. Never had a high reading. WOuld you recommend CYA increase? If so, with what product? Thanks for the responses. By the way, the water looks great :)
 
JCJR said:
I am taking a stab at this but your pool is pretty big, 26,000 gallons. How big is your neighbors and which model do you have?

Also, what is your salt level.
Click to expand...

Neighbors pool has the identical equipment (SWG/pumps/heater...all Jandy) as mine. Pool is roughly 22000-24000 gallons.

Salt level is 2800. Keep in mind that when I heat the hot tub up to 100 degrees, the salt reading indicates the salt level at 3100.
 
cabber said:
WOuld you recommend CYA increase? If so, with what product? Thanks for the responses. By the way, the water looks great :)
Click to expand...
Your numbers look good and wouldn't cause significant scaling unless the pH drifted up higher. If you find that the pH tends to drift up, as is usually the case with SWG pools due to aeration from the hydrogen gas bubbles, then you could lower the TA level (probably not below 80 in your situation) as that can help and will also reduce even further any scaling possibility, but this really isn't necessary unless you find the tendency of the pH to rise a lot.

As for increasing CYA level, you can buy Cyanuric Acid and put it in a sock or panty hose and put it over a return flow -- hanging it from a pole, for example. That's the fastest way to get it to dissolve in just a few days. Otherwise, it can take a week to dissolve if you were to put it in the skimmer and have it caught in the filter, for example. Another alternative would be to use Dichlor which is both chlorine and CYA -- for every 10 ppm FC added by Dichlor, it also adds 9 ppm to CYA. If you used Dichlor, then you would turn down or off your SWG and use the Dichlor as your source of chlorine for a few days to a week, depending on your chlorine usage. A cost comparison of CYA sources is here.

There seems to be a big bang-for-the-buck in terms of protecting chlorine from sunlight when the CYA level approaches 80 ppm so I would add enough CYA to get to at least 70 ppm and see if things improve and if they do, then you can move to 80 ppm and see if that's better. You'll know that the chlorine is being protected from breakdown from sunlight more effectively if you are able to lower your SWG output to maintain the same FC level. Note, however, that at 80 ppm the target FC level in an SWG pool is 3.6 ppm while at 70 ppm it's 3.2 ppm. In your situation with low phosphate levels, you'll likely be able to get away with lower FC levels and not get algae, so could probably maintain 3 ppm FC at 80 ppm CYA with no problems.

Richard
 
Just for reference, I have a Aquapure 1400 My PB initially set it to 45% and the FC was well over over 15. I think 15% kept it around 4-5 late summer and during the fall I kept it < 10% to maintain 3-5ppm. Pool is 21k.
 
If you read the instapure manual they recommend running the CYA at about 75-85 if the weather is warm and you cannot keep chlorine. They also recommend shocking on a regular basis. I would bump up the CYA to about 80 ppm and shock the pool with bleach and then see how it goes. Easiest way to increase CYA is by just adding CYA into your skimmer AFTER cleaning the filter and then not cleaning the filter for a week afterwards. Test the level in a week.
 
Aquapure same issue

This is the exact issue I had with my Aquapure 1400.

I had touble with the FC....my CYA was 30-40 range.

I got the CYA up to 80 and did a big shock with bleach to deal with any possilbe smoldering algee issues.

Bingo!

Now my SGW is down to 30% (for 10 hrs a day) and FC stay 4-6 easy.

From looking around on this site, this issue of the SWG not keeping up the FC levels often boil down to this issue. And the answer often seems to come down to get the CYA levels up.

Good luck! 8)
 
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