Zodiac/ Clearwater LM2-40 SWG

luvrockin

New member
Jun 22, 2010
2
Hello out there, I am new to TFP and I am here hopefully to run the problem I am having across the experts. Here it goes: I have a 20x40 inground pool which holds about 30000 gallons. I have had the pool since 2003 and it is clorinated with the LM2-40. All the years I've had it, I have always been able to make a ton of chlorine keeping it set on the 2 to 3 LED postion and filtering 12 hours a day except for shocking. This year is different, with the chlorinator set as high as it can go, I can't hardly get a chlorine reading. My water is chrystal clear though, the ph is at 7.2 to 7.4. Total alkylinity was low so I brought that up into range. My total hardness looked like it was at zero, so I brought that up to about 200ppm. Lastly, CYA is on the low side, but my pool chemical store is suggesting getting all the other chemicals perfect before adding CYA. The question after all that is, how do you know if you need to replace the cell. My cell is from 2003, 7 years old. Could that be the problem. One last thing, my pool water rand a little low from evaporation, I added about an 2 inches of city water. The next day, my stairs were stained rust alomg with all my jets, skimmers and main drain. The pool place checked for iron and copper. Both were good. Any suggestions will be greatly appreciated.
 

dmanb2b

TFP Expert
LifeTime Supporter
Apr 4, 2009
3,734
NY
I'll let other chime in on the stains...haven't dealt with them yet (thank godness) but I can help you on the SWG. If you are still some FC reading, chances are the cell is still making chlorine. Your # are not far off, but if your CYA is below 60, the swg will have a hard time keeping up with chlorine demand. Raise your CYA to at least 60ppm and if you can, inspect your cell to see if it is dirty. 7 years sound like end of life, but that's not always the case...try cleaning the cell and raising your CYA 1st. :goodjob:

BTW...welcome to TFP :wave:
 

luvrockin

New member
Jun 22, 2010
2
Thank you for the welcome and the reply. How do you clean the cell. It don't look dirty. Just out of curiosity, how important is total hardness in pool water? I went to my local place Saturday to purchase the CYA to get the level up. I was talked out of it and talked into 50 lbs of calcium to the tune of about $180.00. I'm not real happy about that but it's another issue. Just wondering where hardness comes into play. Thanks in advance to any takers...
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
The importance of calcium depends greatly on the kind of pool you have. If you have a vinyl liner then you don't need it at all. If you have plaster/pebble then calcium is extremely important. Fiberglass pools are somewhere in-between, well worth using calcium but not critical.
 

cliff_s

Well-known member
Mar 28, 2007
93
You have probably used up your cell. There are some pool stores that can test your
cell. You might have to call several to find one.

The cell has a special coating on the plates to prevent oxidation, when this
coating is used up the cell will oxidize and not draw any current. The only way to fix this
is to replace the cell.

Cliff