Chlorine usage

[KRAMERK34]

Okay so here is my question to the TFP Guru's...
All my water numbers are where they are supposed to be except one: Chlorine i can't get a reading on it at all right now.
PH is on the money, salt is on the money, TA in on, and CYA is at 90. The water is crystal clear!!
i just can't get the thing to hold chlorine...
We just installed an AquaTrol salt generator and it was working just fine and dandy for about 3 or 4 weeks until just recently.
When i originally installed the unit there were a couple of things about the pool that are not the same as they are now:
1. Stairs were not in the Pool at the time, they are now and they are weighted down with 3 concrete blocks.
2. Pool water was only 75-80 degrees, now it is 80-90 degrees.
3. Weather was over cast most days, now bright and sunny most days.
All of the numbers on the unit say it is working fine.
Do you think one of these or a combination of these is eating my chlorine faster than the aquatrol can generate it?

 

[Bama Rambler]

You need to post a full set of test results. Telling us they're fine really doesn't tell us what we need to know.
In the mean time you need to bring your FC up using bleach.

 

[Poolschoolgrad]

3 things effect the output of chlorine from a properly functioning salt system

1. Pump/filter run time
2. Salt concentration
3. Output percentage

How may hours per day are you running the system?
The Aquatrol is rated for a 18k gal pool, so a 15k gal pool is going to require a fairly high output percentage and extended run times during hotter weather.

Set the output to 100% then
Sequentially press the diagnostic button and post the following
1. Temp
2. Cell voltage
3. Cell current
4. output %
5. salinity
6 produt name
7. Software revision level

While we are troubleshooting your Aqua-trol,
With those water temperatures, you will need to get some chlorine in the water soon.
Add one 184 oz jug of regular 6% bleach. This should raise the chlorine to 6 ppm and increase the salt by 10ppm.

How are you testing the water?
If you could post a full set of water test results, there are a lot of great folks on this site who can help you adjust the water balance to get the optimum output and maximum service life from your salt system.

Another example: High calcium levels can cause scale to build up on the inside of the salt cell. This scaling can substantially decrease the chlorine output of the cell.

PSG

 

[KRAMERK34]

Here are my actual numbers:
FC 0.2
Salt 3100
CYA 90
TA 75
PH 7.5
CH 100

I'll give you the diagnostics numbers from the machine when i get home from work, but when i checked them yesterday they were all within specs for it to be generating chlorine.

Also, i am running the unit 24/7 at 100%. It seems to be generating chlorine(I can get a chlorine reading around 3 or 4 in the early A.M.), just not at a high enough rate to stay in the pool for the duration of the day. :lol:

 

[RobbieH]

What is your CC number? If you bring your FC up to the proper amount, will it pass an overnight FC test with the SWG off?

 

[KRAMERK34]

i don't know the CC number. i don't have my own test kit as of yet since converting from Baquacil.
i do have a "reliable" pool store that will test my water whenever i want for free but i don't get a CC number from them.
i haven't tried an over night test with the generator off.
i have shocked the pool using the pool calculator with 5 182oz bottles of bleach in the late afternoon and checked it again the next morning:
now granted i was looking at the chlorine via a dipstick that only reads up to 10, but i didnt notice a color change on the dipstick the next morning. i don't appear to lose the chlorine until it's been sitting in the sun all day.

 

[JasonLion]

You need to continue adding more chlorine each time the FC level goes down. Lowering the CYA level would also help, but probably isn't the central issue right now.

You most likely have some ammonia in the pool. Chlorine and ammonia react quickly using up both chlorine and ammonia. Eventually you will add enough chlorine to use up the ammonia and will be able to maintain an FC level. I suggest continuing to add 5 large jugs of 6% bleach two or three times a day as long as the FC level remains around zero.

 

[KRAMERK34]

is there an easy way to test to see if i have ammonia?
Also, wouldn't it be cheaper to just use the stuff like Turbo shock or is not as effective since you cant really measure it out?

 

[KRAMERK34]

dont get me wrong, your suggestion makes sense.
i just dont want to keep dumping bleach into the pool if its really a faulty Cell on my generator.
I mean i shouldnt have to run the thing at 100% 24/7 right?
its supposed to be able to handle a 18000 gallon pool and mine is around 14750.

 

[RobbieH]

How old is your cell? (sorry if I missed it). It would help to diagnose if we knew the CC or TC level.

 

[KRAMERK34]

the cell is on 4 weeks old

 

[KRAMERK34]

yea i definately need to get my own test kit.

 

[Poolschoolgrad]

Diagnostics?

 

[KRAMERK34]

ah yes the diagnostics
Sorry i forgot about them

Temp: 89
cell voltage (should be 22-26 when chlorine is being generated) : 24.9
Cell current (should be 2.5-4.0 when chlorine is being generated) : 3.71
desired output: 100%
instant salinity: -3000
prosuct name: AL-7
software revision: r1.45

 

[Poolschoolgrad]

Diagnostics indicate the cell output is correct.

The Aquatrol can increase the Free Chlorine enough to maintain the chlorine level, but you will need to continue the shock process in order to get the chlorine usage to a manageable level.

Here is some additional information on the shock process that Jason is describing:
pool-school/shocking_your_pool

Even with a CYA of 90 your pool is consuming 30 ppm of chlorine per day and the water is crystal clear?

PSG

 

[JasonLion]

You can test the ammonia level with some aquarium test kits. Or you can do an extreme chlorine demand test to see about how much chlorine will be required.

 

[KRAMERK34]

Yep our water is clear as crystal. I could read a newspaper at the bottom if it was waterproof
Ill continue to shock and add bleach until it maintains a proper fc level.

 

[KRAMERK34]

@JasonLion:
Do you still think it could be ammonia(or something else in my water) even though i am gaining FC overnight?
If i check the water when i get home from work i don't get any FC reading via dipstick method, but when I go out and check the water the next morning (6-630 am) and can get a reading around 3 with the dipsticks...
The filter and SWG run 24/7 at 100%
I'm just trying to figure out why if it was ammonia(or something else in the water) why i would actually gain FC overnight and only lose it during the day.

 

[JasonLion]

If you have a measurable FC level at any point, then you don't have any more ammonia in the water. If that has been happening right along, then you never had any ammonia in the water and something I don't understand is happening. However, if that just started happening, then you have just recently gotten rid of the last of the ammonia and things are starting to get much better.

You have a SWG, which is constantly adding chlorine to the water. If it was finally able to build up an FC reading that is a good thing.

 

[KRAMERK34]

yea, im just concerned that it isnt generating enough chlorine to meet the demand during the 90+ weather in direct sun all day.
When i first installed it 4 weeks ago i could get a FC reading at any point in the day(but like i said weather conditions were different then), now i only get one when i go check it first thing in the am.
I'm wondering if there is something wrong with my cell. I mean it's rated for a 18000 gal pool and mine is 14,750 so i wouldnt think i should have to run it at 100% 24/7 and still not get a readable FC during the middle of the day...