Replacing cell in SWCG

[mberry]

We have a Chlormatic CM III saltwater chlorine generator. The chlorine level has been very low lately even with the level set to 95%. Our local pool store instructed me to purchase a replacement cell.

The unit is almost four years old. We took the unit off and cleaned it - not much scale. My question is... do we really need to replace the unit, or is there something else we can try first?

[waste]

Mberry, welcome to the forum!! There are a number of reasons for low chlorine in the pool that have nothing to do with the cell. Low cya (stabilizer) may be letting the sun burn off your cl. Organics (algae etc) could be creating a chlorine demand that your cell can barely keep up with. I'm not saying that this is what's happening in your pool, but it would be a good idea to check it out, get the water tested, if you can't do it yourself most pool stores will test your water if you bring them a sample (take the sample from 18" down in a clean jar or bottle) try to keep the sample protected from sunlight/ excessive heat. They will then try to sell you lots of chems, don't buy any! - tell them you have a bunch of chems in the shed but aren't sure what you have, so you have to go home and check your inventory. Post the results they give you here and we'll help you sort out the results . In the mean time adding a gallon of bleach (unscented) should keep you out of trouble for today (take the water sample before you add the bleach!)
That said, it is possible that you do need a new cell. Your dealer may have a 'loaner' cell that you could use for a day to see if it helps the chlorine level - they should be willing to do this as you'll be buying the new cell from them.
That should be enough for starters. I'll subscribe to this thread and keep my eye on it (I'll be off line for most of the pm running errands and playing a quick 9 holes of golf Good luck! Keep us posted - Waste

[mberry]

Thank you for your reply! We do have a black algae problem that started after we installed a heater. I went to the pool store and asked about both problems at the same time. That's when they said I needed a new cell, and they gave me the following instructions for getting rid of the algae:

Day 1 - 32 oz bottle of Metal Control
Day 2 - 2 to 3 jugs chlor.
1 bottle super black
1/2 gal. acid
Day 3 - 1/2 bottle all-in-1 algecide
Run pump 7 days straight
Brush frequently throughout the treatment w/stainless steel brush

Does this sound right to you? Should chlorine production be increased to 100% during this time? Right now it's at 65%.

[Phillbo]

Get the water sample... This place is a great help but they need the numbers . Make sure the test tells you the Salt level as well.

[waste]

Thank you for your reply! We do have a black algae problem that started after we installed a heater. I went to the pool store and asked about both problems at the same time. That's when they said I needed a new cell, and they gave me the following instructions for getting rid of the algae:

Day 1 - 32 oz bottle of Metal Control
Day 2 - 2 to 3 jugs chlor.
1 bottle super black
1/2 gal. acid
Day 3 - 1/2 bottle all-in-1 algecide
Run pump 7 days straight
Brush frequently throughout the treatment w/stainless steel brush

Does this sound right to you? Should chlorine production be increased to 100% during this time? Right now it's at 65%.

#1 I don't think the swcg units should ever be run at 100% or superchlorinate, the life of the cell is determined by usage and bleach is the same thing your cell generates (~), but much cheeper than a new cell [if I was of a marketing bend I might suggest to the swcg makers to recomend 'augmenting with bleach, when a high chlorine demand occasion arises' , it'll save on cell life and bleach is certainly compatable with the unit.
As for the 'rightness' of their algae advice, it's not the way you would have been told to do it here, if we had your test numbers, but I don't think you've harmed anything, and it might work. As Phillbo pointed out, knowing your water chemistry #s, lets the good folks here offer more aplicable advice. You have a concrete pool (if you don't and they told you to use a SS brush, you've got a good reason not to ever trust them again! ), and I could have given you a couple of suggestions for handling it - dependent upon what your chem #s are.
As you become more familiar with this site, you'll earn an appreciation of how important it is to know exactly what your water's perameters are (FC,TC,CC,pH,Total Alkalinity,Calcium Hardness, and CYA) for it is these that determine how to deal with, or better - prevent, the problems that many people who 'just do what the pool store tells them to do' experience every year. (For starters, when this problem is taken care of and you have some time, give POOLSOLUTIONS a good read, you'll learn SO MUCH about your pool and how to take care of it!!) If I can be of any further service, don't hesitate to ask - Waste