Never I repeat never add salt until you take clen the cell.
Good advice! Salt does not get "used up," and is only lost with water that is not evaporated out - like a leak. When water evaporates, it leaves the salt (and any other mineral, like calcium) behind. So if you haven't "lost" a lot of water to splash-out or a leak, then your salt level is probably exactly the same as when you added the salt to start with. Get a salt test done, (better, get a salt test kit!) before adding salt/draining water.
then a long hack saw blade
I would NOT recommend that. The Ruthenium coating on the titanium blades is only a few microns thick, and you don't want to scrape any of it off, as chlorine production will be severely reduced. I know that other makers supply a "cleaning wand" which is just a pop-sickle like stick of wood. A piece of hard plastic might work too, but never put any metal in the cell.
If you have a high calcium level in your water (and don't control your ph) then the cell plates will foul with calcium deposits, which will reduce the current flow in the cell( which reduces the chlorine produced,) and lead the unit to alarm LOW SALT when the current falls below a pre-set level. The best way to clean off the calcium deposits is with a mild acid solution, ie. white vinegar, diluted Muriatic Acid, and I guess the CLR (Calcium Lime Rust) cleaner should work, too.
The VR1 resistor "fix" allows you to adjust/lower the low current level that triggers the alarm, which will keep the unit producing chlorine instead of alarming, - HOWEVER, with a reduced current flow, the chlorine production is also reduced, and may be so reduced as to be ineffective. That is why you MUST take accurate chlorine readings daily (test strips won't do it.) Keeping the cell clean by maintaining proper water balance will keep chlorine production at a high level, and cleaning the cell when you notice the level dropping will help it last longer. As the cell fouls with calcium, you will need to run it longer to get the same amount of chlorine, so it will foul even more, so you will need to run it even longer.....
A Taylor FAS-DPD chlorine test kit is considered the best by many people, as you can test up to 25ppm at 0.2 ppm resolution quickly, accurately and repeatedly using titration, which involves noting a change from a pink color to colorless, not trying to match shades of yellow or pink. An indication of Combined Chlorine at the same ppm resolution occurs if it returns to pink again as the last part of the test. A CC reading above 0.5 is an indication that something like algae is using up your chlorine, and things can quickly get out of control, unless you take action!
I am not familiar with your model, but I think that the green LED only comes on when the cell is powered (to show chlorine is being produced.) The 8110 goes through a start up routine that checks for a programmed run time (code 88 if not set,) water flow ( code 90,) Low/High salt codes 91/92. Code 93 means that it successfully completed a cycle and will soon hibernate (blank display) until next start time comes.
You may want to make sure that there is not a Reset button that needs to be pressed (or a tripped GFCI outlet), and that the unit indicates that it is getting power (amber LED.) I had a unit die on me, it would seem to be OK and take a program time set, but then it would start to flash all of the 7 segment LEDs and then go dead, each time it died quicker, then it wouldn't come on at all. Intex replaced it for free, as I only had it for a few weeks, I think that they have a 2 year (probably pro-rated) warranty.
Good Luck!, and Best Wishes!