new salt chlorinator system

[buddy97]

Great site. Just installed a salt chlorinator system here in northern Alabama. I can't wait for warm weather. All is working wonderfully, but I would like to read about the problems I can expect. Just want to stay up with issues. Is there a forum thread that is toward that end? And, are there any BBB ideas that I can use with this system?

[PoolDoc]

An SWCG -- salt water chlorine generator -- is just a METHOD of chlorine, so almost everything applies.

[mas985]

The biggest complaint by many SWCG owners, including myself, is PH rise. This can be controlled some by lowering TA unless you have high TA fill water with high evaporation like myself and then you will need lots of acid.

[kelemvor]

The biggest complaint by many SWCG owners, including myself, is PH rise. This can be controlled some by lowering TA unless you have high TA fill water with high evaporation like myself and then you will need lots of acid.

I'll second that, but I prefer adding acid weekly over adding bleach daily!

[waterbear]

pH control is moer than just adding acid or lowering TA. The main cause of pH rise with salt systems (excluding such factors as new, curing plaster) is outgassing of CO2. The outgassing is minimized by a multifaceted approach:

1. Keep CYA at the manufacturers MAXIMUM (usually 80-100 ppm) and run the FC at 5% of the CYA level. This translates into a shorter cell on time, which translates into less generation of hydrogen bubbles in the cell, which tranlsates into less aeration of the water, which translates into less outgassing of CO2, which translates into slower pH rise.

2. Lower the TA to around 70 ppm (or even a bit lower). If the pool is plaster (or fiberglass since there is some emperical evidence that higher calcium might help lower the tendency toward staining) then raise the CH to maintain the calcium saturation index. Lower TA means less bicarbonate in the water. Less bicarbonate means less outgassing of CO2 which means slower pH rise,

3, Do not let the pH go above 7.8. When it does do not lower it below 7.6. (This is actually easier to do than it sounds with a bit of trial and error on how much acid to put in or you can use an acid demand test to get an idea of how much acid you need. ) The lower you put the pH the faster it will rise because you convert more bicarbonate in carbonic acid (essentially CO2 dissolved in the water) which then outgasses.

4. Add 50 ppm borate (easy to do with borax and acid) to provide a secondary pH buffer that work with the bicarbonate buffer we call TA and effectively keeps the pH at 7.7 to 7.8 for a longer period of time then without the borate.

When these 4 steps are done together pH rise and scale buildup in a salt system can be minimized.

[JimK]

......
1. Keep CYA at the manufacturers MAXIMUM (usually 80-100 ppm) and run the FC at 5% of the CYA level. This translates into a shorter cell on time, which translates into less generation of hydrogen bubbles in the cell, which tranlsates into less aeration of the water, which translates into less outgassing of CO2, which translates into slower pH rise.

.....

My appologies to the OP for being off topic, but his item caught my attention.

My SWG (Aquarite) recommends a CYA level of 60-80 (80 being ideal). So keeping CYA at 80, 5% of that results in a recommended FC level of 4. This is lower than recommended on the "Best Guess" chart (Best Guess chart says min FC of 5 at this CYA level).

Could you clarify this for me? If I can keep FC at 4, this will save some wear on my salt cell (which is a good thing considering the cost of replacement cells!).

Thanks.