Let me just point this out to the thread followers, don't expect your tank to last forever.
I think, at least in this thread, I have the highest volume of records cleaned, as such I'm on my second tank. The first tank died on me after cleaning 1600 records, and here is what happened that I know of since I could not fix it.
8 records at a time running 10 minute cycle, completing 1600 records is around 36 hours run time on the motors.
The internal fan only runs while the sonic motors are on. Since there is a fan inside something needs to be cooled, kept cold. The heater and motors are on two different switches and the fan shares the motor switch.
Although it seemed my motors were getting weak what finally killed the unit IMHO was the high heat. I was preheating the tank, and normally don't have the lid on for this. However, one night I did leave the lid on and walked away, I fell asleep for about an hour or so. When I got back to it, the tank, lid and water were super hot. After cooling a bit and cleaning some records the next day I noticed that the motors were not working anymore.
My deduction is...
I don't use the tank heater to preheat the tank.
I don't run the motors unless I'm getting some records cleaned.
When I start my cleaning I take that time to filter the water into a big pot, I heat it on the stove, clean out the tank and ready it for my cleaning session. If I stop for a while I turn the unit off so the heaters are not running.
You all can do what you want, but just remember you want to get as many records cleaned as you can with the tank. So if you burn it out early because of running the heater or motors without any records.... it adds to the per record cleaning cost.
I'm at around 3200 discs and my second tank and this tank is still running very strong. It took me one tank and at a cost of $350 to learn what not to do, and to realize the tank is going to have a life span.