A lesson learned for me....
had a lot of leaking into the atty and around the tank recently and wasting a lot of fluid obviously into the bargain
I was convinced it was the atty(s) that was giving up the ghost (both of them actually as I`ve been using 2 in rotation for over a month)
then I decided to change the plastic cap on the tank itself - problem has gone - it was simply the holes were getting too big on the tank caps, 3 of them all at the same time.
