CYA for Salt Chlorinator Pools...

[Karin]

Hi folks....I'm new, but eager to be part of this 'wet ' wild' pool community.

My present concern is about the best CYA level to maintain for a pool using an Aqua Rite Salt Chlorinator. I recently drained and refilled some of my pool in order to reduce the CYA from 100ppm to about 40ppm. I would really like to stay in this range, but for some reason the manual suggests 60-80ppm.

Does anyone else have a SWG system and what do you keep your CYA at? Why would a salt system need higher CYA?

Thanks in advance. Karin

[tonyl]

The higher CYA helps the chlorine stick around in your pool longer. That allows you to run with a lower output setting on the SWG. I've had one for several years with cya of 70-80 and 1-2ppm chlorine with great results. I only add bleach after very heavy rains. Hope this helps, Tony

[Karin]

Thanks Tony....that does help. How long do you run your SWCG each day? It seems that mine is way too eager to please and my chlorine level is up at 6ppm after running the pump/filter/Kreepy thing for about 6-8 hours each day.

I know I can adjust it downward and I do....but we just had a horrifying experience with yellow algae and now I'm nervous that the alien algae will return.

[gwrace1]

I run my CYA at 35-40PPM with a FC level of 2.5 PPM. Aquarite is set on 40% and runs for 12 hours each night with pump on low speed. Water is always crystal clear.

[tonyl]

Well for our pool my output is up a bit this year due to the hot hot summer so far here in the midwest. I'm at 50% and 8 hours per day. Water temp is 91.

Edit: forgot to mention it's more efficient to run with salt at the higher end (3400), your output is also dependent on the salt level.

[rbonin]

The high recommended CYA level by most salt water chlorinator manufacturers seems to be a mystery to most on this forum.

I abide by Ben's "best guess" chart of CYA vs. FC and so I keep my pool at 40ppm CYA and about 5ppm FC. My Polaris AquaClear cell runs 10 hours a day as my pool is in direct sun all day.

[mas985]

I am interested in everyone's settings as well, since there seem to be many different lines of thinking on this:

1) Use recommended CYA 60-80 and keep chlorine level per Ben's CYA table.
2) Use recommended CYA 60-80 and ignore Ben's CYA table and rely on cell to continuously shock water plus add bleach when necessary.
3) Use lower CYA level and Ben's CYA table. Recent studies indicate the CYA can contribute to dissolving plaster and shortening it's life.
4) Use lower CYA level, ignore Ben's CYA table and rely on cell to shock water.

My current preference is #4 since I have a plaster pool and not quite at Ben's CL ppm. I am operating at a CYA of 30, 21000 gallon pool, setting 90% and run the pump 6 hours a day. I am able to maintain 2 ppm. I have calculated that with my current settings, the cell puts in about 2 ppm per day so I figure I am using up 2 ppm per day.

If anyone is interested, the aquarite/logic cell puts in 1.45 lbs/day @ 100% setting. This is equivalent to 1.45 gallons of 12.5% bleach.

I think if I upped the CYA with the current settings, the chlorine would probably rise but not as quickly as per Ben's table. I am trying to research this a bit more to see if I can predict a chlorine ppm level with different CYA levels. I would love to experment with different CYA levels but given the difficulty of reducing CYA, this is not an option.

[cwstnsko]

Agree with the previous post about following Ben's guidelines. I run my CYA at about 30 ppm. I adjust the SWG so that my FC is at about 5 ppm in the morning, and it drops no lower than 3 ppm by late afternoon in full AZ sun. I run my pump on low speed 24/7, SWG at about 30% on power level 1, salt is at 2900-3000.

[Karin]

I've heard that using my SWCG to shock will hasten the cell's life expectancy. I don't want to hasten its demise and will probably use good ole bleach on the occasions it may need some shocking--after heavy rains.

I can only run my pump at one speed. It can adequately turn my water in a 4-6 hour period, but I leave it on for 6-8 hours....it usually starts at 8am. Should I maybe have it start later in the morning so that it runs during most of the hot afternoon part of the day and keeps adding fresh chlorine that way?

Based on your comments, I'm leaning toward a CYA of around 50---close to Ben's recommendations and also Aqua Rite's. How's that for straddlin' the fence?

Tell me more about CYA staining??? I added some the other day through the skimmer---tried to dissolve it with some warm water first, but that stuff doesn't like to dissolve, and then slowly poured it into the skimmer while it gulped it down.

I presently have some yellowish stains in corners and the risers of the steps and along the walls in the deep end that appear to be recent. Since we just had it resurfaced with some Diamond Brite in March, I'm very concerned.

We had a bout of yellow algae about a week ago---which I think is gone. (Cleaned the filter daily.)
We did a partial water change to lower the CYA only to find out that the city water was full of phospates....plus I forgot to add a sequestering agent till after it had been filled. Then after going to 4 pool stores and getting 4 different CYA readings of : 15, 25, 30 and 60 all from the same sample, I added some CYA to bring it up to 40. Yes....I do need a life...

So now I'm wondering what the culprit is for the stains:

From the Yellow algae?
From the new water full of phosphates etc?
From the additional CYA?

Other than for the stains, the pool and water look great: clear and blue....sigh..I should be in there right now instead of typing about it....
FC 6.5
TC 6.5
PH 7.4
Hardness 200ppm
Alkalinity 100
CYA 40
Salt 3100

[Simmons99]

I've never heard of CYA staining - it could be due to metals or algae