My eco cell had scaling and I cleaned it as indicated, now it's showing my salt is too high. Why is it going back and forth like that?

SOURCE: We just replaced the T-cell for our pool. We were

Sound to me that you added wat to much salt.
If you are using a salt test kit that eads in colors throw it away and get a kit that reads in #.s
If you are using the one with #'s then proceed to getting your water to as close to 3000ppm as possible
Drain 20 % water ad fresh and check again keep doing this ti'll you get close to the 3000ppm

any lower than 2800 and you can read low salt and worse of all you will not produce enough chlorine any higher than 3500 and you will go cloudy and read high

It is my opinion that you were low salt and then adding to much salt put you to far to high

remeber anytime you add salt you should filter only for 12-24 hours to distribute the salt properly so the unit knows what it is reading

While adjusting your salt level clean your new cell with vinegar let it soak for a few hours You should have received a cap to cover one end of the cell while soaking
once cleaned it will not grab hold of the salt water until the generator is turned on

Just remeber 3000ppm

SOURCE: I have a 12,000 gallon

any thing over 3500 can create alarms.

First of all make sure you are useing a test kit for salt that reads in #'s not color

your system can read low salt when it is high or even high can read low
The system only really knows something is wrong

your 7800ppm is ridiculously high

Now start draining 20% of your water at a time and refilling giving the system at least 6 hours of just filtering between drainings until you get to as close to 3000ppm as possible

under 2700ppm and you will not produce enough chlorine and can trigger alarms any higher than 3500ppm and you can trigger alarms,go cloudy, and not to mention corode any metal parts like an aluminum ladder

once you get the ppm to 3000 clean your cell one last time and you should be good to go

I would also check your water for metals since you used well water.
you may need to get a metal reducer to add to the pool

SOURCE: We have a 18x48 ultra

I can't explain all of this but to get the rid of the green and reduce the salt level you need to drain half the water and refill. At this you need to shock it so the chlorine is up to about 10 ppm. You need some way of testing to tell this. If your chlorinator is ok then when you start the pump and chlorinator it should continue cleaning it out. The dead algae will be filtered out with the filter. If the flow slows down you will need to clean the filter with a water sprayer on a hose. I hope this helps.

SOURCE: Code 91 beeps even when my salt readings are 3200 PPM

***This is how you fix the unfixable code 91***

Code 91 is generated by lack of conductivity between plate 1 & plate 3 of the titanium plate set. This can be caused by 3 possibilities.

1. The salt is low - easily tested
2. The Plates are covered with lime scale - easily cleaned with vinegar
3. The one or both of the connections to the plates are corroded and there is
a break in the circuit

I took a meter to my salt cell ( the tube with the plates in it). The outer 2 plates should have continuity with the plug prongs on their respective sides (where the unit plugs in to the control unit) The middle plate is not connected to either plug.
One of my prongs did not have continuity to the plate (thus the cell generated a code 91 - because there was no voltage to detect.

I took a dremel tool and cut a one inch square out of the back of the housing. I then used a round ball bit in the dremel to remove the plastic around the back of the prong. The back of the plug is conneted to the metal tab that is attached to the titanium plate via a 9/32 post and nut. What happens is that water intrudes from the seam in the front of the prong and corrodes the bolt face and the tab surface creating the break in the circuit. I removed the corrosion and applied dielectric grease (used on headlight bulbs and available at the auto parts store) to the back of the nut and the shaft of the bolt and reinstalled. I tested with the ohms/resistance setting of my multimeter and found the circuit complete.
I then applied a covering of epoxy to the post and bolt and replaced the one inch piece of plastic that I removed and epoxied over the area. I sealed the front of the prongs with epoxy- there is a small area where the metal and plastic meet where the water entered. After reinstallation and hooking the machine up it functions perfectly. Intex is sending me a new unit under warranty-- as soon as it arrives I will seal the front of the prongs with some epoxy and store just in case.

SOURCE: the cell does not read the correct salt level

Test your salt level with a Taylor salt kit to see what the actuall PPM is. You should be betwen 3200 and 3700. There is that possibility that your cell has developed a fault. Kit available at your pool supply place.