Intellichlor IC40 Low Salt but reads fine

[drharris]

I just bought a house with a salt water pool, never having owned a pool before. Literally 3-4 weeks ago the seller showed me how to use everything, and all was working perfectly. 2 weeks ago, we moved in and had immediate issues with the IC40 SWG. I noticed yellow algae forming, and that the flow light was red (and zero chlorine level), so I backflushed the filter and cleaned out all the baskets, let it run, but no luck. I took a sample and the IC40 into the pool shop and they noticed the flow sensor was messed up (it was missing the little metal paddle that should have been there to measure flow, which I still haven't managed to find). A couple hundred bucks later and I had a new flow sensor and lots of chemicals to get algae killed and my chlorine levels up in the meantime.

So, I got the chlorine issue fixed, installed the IC40, and let it run. The flow light corrected after a little while, but then the Low Salt red light came on. I knew this was a problem, because the pool store measured 5000 ppm, and I could still taste the salt in the water (I have heard you should be able to just barely taste it, if at all). So, I cleaned the cell with muriatic acid, hoping that would fix it, but I didn't get any bubbling at all. I also noticed my pool water level was probably a bit low, so I ran the garden hose for a few hours to get it up to the middle of the skimmer. Still didn't fix it. I then called the pool company out and they said they tried cleaning it and it didn't work, so my cell must be bad. You apparently can't replace that salt sensor?

I guess my question is if there's anything else I should try. This is way too big a pool to keep filling it pool supply store priced chlorine sticks and all my other chemistry seems out of balance (until I can get chlorine in shape). Is my SWG cell really dead? I believe it's only a few years old. Did replacing that flow switch mess up the salt sensor, or could those be related? Is my best bet to just buy another IC40 and replace it?

 

[NeedMoreSun]

There isn't an actual sensor. It uses voltage, current, and temp to calculate it. Since it was already in the store for them to find the broken flow switch were they not able to fully test it while there as well, or maybe they don't have the ability? Reading low and cleaning didn't help it's likely dead, but 100% sure wait for other input before drop kicking it down the street!! Could still be something else!

 

[drharris]

I don't think they would have the ability to fully test it. They use Pentair products in installations but I don't think they show up as "Pentair-authorized techs". However, you mentioned it uses temperature - I know the flow switch also has a temperature sensor on it. Could it be that installation of the new flow switch has messed up temperature readings and thus caused the salt level to calculate incorrectly?

 

[NeedMoreSun]

Hopefully someone who knows Pentair comes along soon I'm pretty sure the temp and flow are all in that one switch and they just replaced it though. Unless they got a couple of the four wires swapped around it should eliminate that as the issue.

 

[drharris]

I just saw I never updated this for anybody who might come along.

In the end, I had to just buy a new IC40. Despite the new flow switch and a cleaning, the original one just wouldn't work. I now use it as a dummy cell for the winter months. A new cell worked just fine.

I think I was able to piece together the chain of events. Once I got the algae and chlorine issues solved, there were a few problems. Salt was sky-high, like 5000ppm, and it didn't really go down by the end of the season. Alkalinity was really, really low, and hardness was really off too. My best guess is the hardness and alkalinity problems caused the original cell's temperature/flow switch to stop working and report low salt. The owner kept dumping salt in there to get it working again while waiting to close on the house, but likely not using it much during that time. By the time we got it, everything was so out of balance that the flow switch broke clean off, and the cell itself was damaged past repair.

This season we had the liner replaced under warranty (faded too quickly but previous owner didn't get around to replacing it), so it gave us an opportunity to start from scratch with better levels. Still getting it initially balanced but it looks like the new cell is working better than expected (4.1 FC level after 2 days in boost mode after initial salt). Now I have a ton of other stuff to balance, but I learned a lesson about keeping an eye on everything, not just pH and FC.