Ok, I'm sure this has been answered before. I've read through the forums on this code quite a bit and nothing has worked yet...
I have model 8111 SWG with the 16' x 4' pool. The setup is starting it's 3rd year now.
After dumping salt in it several times it was still reading low salt. Off to the store to buy some test strips. Salt showed almost 5000ppm, so as I suspected, it had way too much salt, but still reading low salt. I disassembled the filter, capped the one end of the clear tube by the copper and filled it with white vinegar as I had seen on many posts here. Let it sit for 3+ hours, the plates looked clean, so I dumped the vinegar, rinsed out with the hose, and reassembled. Still reads low salt. Disassembled again and let soak in vinegar for about 18 hours. Still reads code 91.
As already mentioned, salt shows about 5000ppm, here are the rest of the readings:
Total Hardness: 0
Free Chlorine: 0
Total Alk: 40
Please help! Am I getting a low salt error due to the other readings being off? Is my SWG dead?