I have the M500--Same as yours but with a nearly useless Bluetooth connected app (indeed, I have the program set to bottom and sides and a 3.5 hour run cycle and never change it.) What I find appealing about this cleaner is
- Three brushes vs the typical two, with the third brush in the center of the bottom, between the two vacuum slots. That third brush rotates counter to the front and rear. I believe that is why it seems to pick up everything big and small, even Sahara dust mud.
- With the floats properly adjusted, it cleans right up to and slightly above the water line.
Negatives, and these may apply to other robotics as well: it needs water at least about 18 inches deep, so it won't clean a sun shelf; it also won't climb my steps; when it encounters things on the wall (drains, lights), it just backs down and moves on; and...this sucker is heavy which by now you know, and it's especially heavy coming out of the water until it drains (my wife cannot lift it out of the water.) I assume you wouldn't try to pull the cleaner out of the water by the cord! Finally it's too big to do much of anything in our attached spa.
After my approximately weekly run, I remove it from the pool to clean out the filter compartments and--with the cleaner on its side with the two doors open--thoroughly hose inside and out with fresh soft water--and I mean thoroughly. I don't leave an expensive machine to dry with salty chlorine water on plastic, rubber, and metal parts. I also hose off the low voltage power cord, especially the swivel joint. Then I put it on the caddy to dry, after which I have an old chair cover I put over it to protect from the sun, although the thing is stored on a covered patio.
You probably don't know how the previous owner used the one you bought. If it was left in the water, it could have had chlorine that has seeped inside. If the bearings have been recently replaced it might have been left in the chlorine water for extended time. Hopefully, the repair service did a cleaning as part of their repair. If you employ my OCD approach to cleaning after use, I suspect after a few runs it will be free of old chlorine and salt residue and you will have a bargain priced excellent cleaner.
