Aqua Plus generator issues

[dschlic1]

My Aqua Plus salt water chlorine generator with a T-15 cell has stopped producing chlorine. It is under warranty, and I have asked both the pool builder and Hayward to repair it ASAP. However I would like to open a discussion as to what is the problem.
Around the beginning of the month, the system started to give me low salt errors. Previous to that, it was giving salt readings of 3000 to 2900 ppm. I would clear the error and it would start working again, only to trip out hours later. I opened a tech support case with Hayward on the erronious salt readings. They sent me a "recalibration" procedure which consisted of updating the time average salt value with the instantous one. Of course this did not work.
On 12/08/2007 I had the water analized by a pool store, and the salt level was 2800 ppm. I also purchased some salt test strips, and they gave the same reading. The range for my generator is 2700 to 3400 ppm. I then added 20 lbs of salt, which cured the low salt errors on the generator.
The next Monday I tested the water and had 0 free chlorine. I added one quart of 10% bleach, and waited one hour. The free chlorine level still tested zero. I the decided to shock the pool. According the the Pool Calculator I added an additional gallon of 10% bleach. This raised the FC level to above 10 ppm. This level took a long time to come down, by 12/15/2007 it was about 3 ppm.
The level continued to drop, so I raised the output on the generator. For the previous month a setting of 7% was giving me a FC level of between 3 and 4 ppm. I continued to raise it finally reaching a level of 25%! By this time the FC level was down to .25. The evening of the 20th I ran the SWCG in superchlorinate mode for one hour. This raised the FC level to .94. Again after that the levels still kept dropping. On the 22nd I said enough, and shut down the SWCG and started to add bleach. The readings after adding 32 oz 10% bleach:
FC 3.9
TC 4.0
pH 7.4
TA 85
CH 285

While the SWCG was working I took the following readings from the diagnostics: +26.59V, +5.99A, 73F, 3000ppm. I removed the chlorine cell and inspected it. The plates were shiny and clean. All I saw was several small pieces of plastic (probably burs from the pipe). So my questions is what can prevent a chlrine cell from producing chlorine?

 

[Guest]

You did not state your water temperature. Conductivity decreases with lowered water temps and the SWG will interpret that as a lower salt level and possibly give a low salt error. Running your salt on the higher side (around 3400-3600 ppm) will help prevent this until the water temp drops low enough to shut the unit off. This is actually normal operation for a SWG. They just don't work in cold weather (and really don't need to since the chlorine demand goes WAY down in cold weather!).

 

[dschlic1]

I not only live is west central Florida, but also have solar heating. My water temp right now is 77F. Last week it was 84F. So temperature should not be an issue.

 

[JasonLion]

It sounds like you have ruled out most of the common causes: low salt levels, cold water, calcium scaling of the cell plates, and algae in the pool. That only leaves the CYA level as a possibility. I didn't see a CYA level in your message. Low CYA levels can cause problems like the ones your describe. CYA should be around 60 to 80.

 

[dschlic1]

The stabilizer level is a possibility. I have started a seperate thread under the chemistry 101 forum about that issue. However I am currently adding bleach to maintain chlorine levels. In 24 hours my FC decreases about one ppm. I am adding 8 to 10 oz of 10% bleach per day. This, if nothing else, is an indication that my stablizer level is within the correct range. It also gives an idea of the amount of chlorine needed per day. This amount falls inline with the setting I was using before the problems developed.

 

[repair_guy]

You also don't say how long that pump is running. I saw the 77 degrees on the readout and 7-25% is nowhere near what I would have expected to see. At 80+, I'd want to see an 80-90, if not 100% output on 8-10 hours run before I would come out. You said it generated to 3-4 ppm so it WAS working.

 

[Guest]

You also don't say how long that pump is running. I saw the 77 degrees on the readout and 7-25% is nowhere near what I would have expected to see. At 80+, I'd want to see an 80-90, if not 100% output on 8-10 hours run before I would come out. You said it generated to 3-4 ppm so it WAS working.

His pool is only 7.5k gal so with the T-15 cell and an 8 hour pump run time he should have extremely high chlorine levels with an output percentage above 30% if the CYA and pH are within recommend range (60-80 ppm and NOT above 7.8). The range of 7-25% is just about what I would expect with an 8 hour run time in a pool that size to maintain about a 4 ppm FC level. I would put the unit in boost mode first and see if the chlorine level rose. This runs the cell at 100% for a period of time (default is 24 hours but this is user adjustable).
I would also get a water sample directly from the return while the cell is operating (or better yet, disconnect the cell and collect water right from it) and test it. The chlorine levels should be much higher than the water in the pool if the system is operating.

 

[Guest]

The stabilizer level is a possibility. I have started a seperate thread under the chemistry 101 forum about that issue. However I am currently adding bleach to maintain chlorine levels. In 24 hours my FC decreases about one ppm. I am adding 8 to 10 oz of 10% bleach per day. This, if nothing else, is an indication that my stablizer level is within the correct range. It also gives an idea of the amount of chlorine needed per day. This amount falls inline with the setting I was using before the problems developed.

OK, here's my take on the problem. You have lost salt and your stabilizer is deceasing. You are testing with a colorQ which does NOT test for high levels of calcium (The limit of the system is 400 ppm but in reality anything over about 300 ppm will NOT test properly and will test low (a drawback to all LaMotte colormetric CH tests. The $1000 Waterlink shares this problem.) You stated that when you inspected the cell it looked clean except for 'some plastic burrs'. I suspect they are calcium deposits and would recommend acid washing the cell and see what happens. Also check your calcium levels with a titration test (or get Taylor or HTH 5 way strips, the HTH are simply rebranded Taylor ones, to see how high the total hardness is. Total Hardness is not the same as calcium hardness but if it tests high then you know that the calcium hardness is also going to be high. This is the only strip I have found that is worthwhile for this test.) I suspect you will find the hardness is higher than you expect. I also suspect that the 'burrs' that you saw were actually scale in the cell.
The loss of salt and CYA indicate a possible leak somewhere. The most common places to check first are the light niche and the skimmer. You can also do a bucket test. Fill a 5 gal bucket with pool water and place it on the steps of the pool. Mark the water level in the bucket and also mark the water level in the pool on the tile line. Let it sit for a week. The wate level in the bucket and the water level in the pool should be about the same if there is no leak. If there is more than about a 1/2" difference in the water levels in the bucket and the pool you have a leak.

Just my 2 cents. Hope some of it is helpful.

 

[dschlic1]

I think I may have found the problem with the SWCG. Several weeks ago (about the same time I was having the generator shut down for low salt), the pool builder installed the solar heater. This morning I noticed that when the solar heater valve opens up, a rather large amount of air is pushed through the returns. I believe that this is causing the flow switch to indicate no flow and shut down the SWCG.

Today after this happened, I restarted the SWCG, with the setting at 25%, and have a FC of over 4% this evening. Now I have to figure out how to get the SWGC to reset itself.

All of the test values (except the CYA) from the pool store (using Taylor reagents) are in line with the ColorQ values. The shards are plastic, I removed several of them that I could get to.

 

[dschlic1]

An update on my SWCG problem. I last stated that it looked like air in the return line from the solar heater was causing the chlorinator to trip out. While it looks like this may occasionaly happen, it does not happen on a continual basis. Some history:

Up to 12/31/2007 I had been maintaining the chlorine level using bleach. However I was maintaining the chlorine level at the value recommeneded for SWCG which was about 4 ppm. Up to this point I was added 8 to 10 oz of 10% bleach daily. On 12/31/2007 I decided since I was using bleach, I should raise the level to the range recommended when using bleach which is 7 to 12 ppm. On that afternoon I added 48 oz of 10% bleach. My readings before adding bleach: FC:3.1, TC:3.3, CC:.2, pH:7.5, TA:81, CH:296, CYA:90. The added bleach should have raised the FC to about 8 ppm.

On that date I also purchased a solar pool cover and installed it as we were going to have a hard freeze for the next several days. This cover was left on the pool until 1/04/2008.

On 1/2/2008 a Hayward service tech came out to inspect the equipment. I had requested that I be given a call before they came onsite but of course this did not happen. Well the tech found that the chlorinator was set to zero, and stated in his report that this was the problem. H then set the unit to 75%!

I was not able to test the water until the afternoon of 1/03/2008 and the results: FC:6.7, TC:7.8, CC:1.1!, pH:7.9, TA:87, CH:323. This was the first time I had ever seen any significant amount of CC! As the temperature that nigh was still suppose to be very cool, I did not remove the pool cover.

The next day I again tested the water and removed the pool cover for a short time. The results: FC:7.5, TC:8.1, CC:1.4, pH:8.1, TA:89, CH:327. Water temperature was 66F. I then added 32oz of acid and 2 lbs of Baking soda. Pool cover was placed back on for the night.

On Saturday morning, I removed the cover for the entire day. I also brushed down the entire pool, vacuumed the pool, emptied the skimmer strainer and the pump srtrainer. I also changed out the filter cartridge. At the end of the day the test results: FC:9.2, TC:9.7, CC:0.5, pH:7.5, TA:93, CH:308. Water temperature 73F. I added another 2lbs of baking soda and set the SWCG to 10%. The results on Sunday evening: FC:9.2, TC:9.7, CC:0.5, pH:7.6, TA:102, CH:306, water temp 78F.

From the above I have come to the following conculsions:
1. I have (and had) an ongoing organic load in my pool. This load is decreasing.
2. Using bleach at the lower levels recommended for a SWCG did not react with this organic load.
3. The super chlorination within the SWCG cell was reacting with this load to the extent that all generated chlorine was being used when operated at the regular lower settings.
4. With the pool uncovered all combined chlorine being produced was being dissapated as quickly as it was formed resulting in very low values of CC.
5. The SWCG is producing chlorine. At 10% the SWCG is maintaining the chlorine levels which it previously had not been. This value is close to the value it should be at (7%).

I do not want to shock the pool because of the very high chlorine levels needed. My current shock level is about 23 ppm. I am going to maintain the FC levels above 8 for the time being and leave the pool uncovered.

 

[Guest]

An update on my SWCG problem. I last stated that it looked like air in the return line from the solar heater was causing the chlorinator to trip out. While it looks like this may occasionaly happen, it does not happen on a continual basis. Some history:

Up to 12/31/2007 I had been maintaining the chlorine level using bleach. However I was maintaining the chlorine level at the value recommeneded for SWCG which was about 4 ppm. Up to this point I was added 8 to 10 oz of 10% bleach daily. On 12/31/2007 I decided since I was using bleach, I should raise the level to the range recommended when using bleach which is 7 to 12 ppm. On that afternoon I added 48 oz of 10% bleach. My readings before adding bleach: FC:3.1, TC:3.3, CC:.2, pH:7.5, TA:81, CH:296, CYA:90. The added bleach should have raised the FC to about 8 ppm.

On that date I also purchased a solar pool cover and installed it as we were going to have a hard freeze for the next several days. This cover was left on the pool until 1/04/2008.

On 1/2/2008 a Hayward service tech came out to inspect the equipment. I had requested that I be given a call before they came onsite but of course this did not happen. Well the tech found that the chlorinator was set to zero, and stated in his report that this was the problem. H then set the unit to 75%!

I was not able to test the water until the afternoon of 1/03/2008 and the results: FC:6.7, TC:7.8, CC:1.1!, pH:7.9, TA:87, CH:323. This was the first time I had ever seen any significant amount of CC! As the temperature that nigh was still suppose to be very cool, I did not remove the pool cover.

The next day I again tested the water and removed the pool cover for a short time. The results: FC:7.5, TC:8.1, CC:1.4, pH:8.1, TA:89, CH:327. Water temperature was 66F. I then added 32oz of acid and 2 lbs of Baking soda. Pool cover was placed back on for the night.

On Saturday morning, I removed the cover for the entire day. I also brushed down the entire pool, vacuumed the pool, emptied the skimmer strainer and the pump srtrainer. I also changed out the filter cartridge. At the end of the day the test results: FC:9.2, TC:9.7, CC:0.5, pH:7.5, TA:93, CH:308. Water temperature 73F. I added another 2lbs of baking soda and set the SWCG to 10%. The results on Sunday evening: FC:9.2, TC:9.7, CC:0.5, pH:7.6, TA:102, CH:306, water temp 78F.

Two things, a solar cover can cause CC to accumulate in the water so I would not worry too much about that unless they cannot be removed by shocking and exposure to sunlight. and air. Second, why are you inceasing the TA? Keep it between 70-90 ppm for the best pH stability with a SWG!

From the above I have come to the following conculsions:
1. I have (and had) an ongoing organic load in my pool. This load is decreasing.
2. Using bleach at the lower levels recommended for a SWCG did not react with this organic load.
3. The super chlorination within the SWCG cell was reacting with this load to the extent that all generated chlorine was being used when operated at the regular lower settings.
4. With the pool uncovered all combined chlorine being produced was being dissapated as quickly as it was formed resulting in very low values of CC.
5. The SWCG is producing chlorine. At 10% the SWCG is maintaining the chlorine levels which it previously had not been. This value is close to the value it should be at (7%).
Where are you getting that your SWG should be at 7%? Every pool is different and the output percentage is just one factor. It's certainly in the ballpark for a pool your size but then again so is 10% or even higher!
I do not want to shock the pool because of the very high chlorine levels needed.

Why not, It seems that this is what your pool needs. Just shock it and be done with it!
My current shock level is about 23 ppm. I am going to maintain the FC levels above 8 for the time being and leave the pool uncovered.

This is not going to solve the problem if there is a lot of CC, expecially with a CYA of around 100 ppm. Just shock the darn pool and be done with it.

Honestly, sometimes I just don't get the strange ideas that people get about their pools. It's not rocket science but we really have a good idea of what is going on and then you need to shock and how high you need to shock is pretty well understood.

Your problems would probably not even have happened if you had started with a drop based test kit instead of relying on the colorQ, with all it's documented problems, and test strips (although the HTH strips are rebranded Taylor ones and are one of the better strips out there, as far as strips go) and pool store testing and by reading and following all the stickies on this forum!

Sorry if that sounds harsh but it's the truth!