Today I mixed a solution of 1 part household bleach to two parts hot
water and sloshed this over the mildew on top of my tower's concrete base.
With just a bit of encouragement from a plastic kitchen scouring pad (and
rubber gloves) I was able to remove all the greenish material. I followed
the cleaning with a rinse in cold water from a garden hose. This is the
first time in a long time that I've been able to see a whitish block of
concrete from the back deck, rather than the awful green slime that had
covered it. I'm sure the chlorine will have some effect on the grass around
the tower, but I'll live with that. A power wash might be a better idea (to
preserve the grass), but I had the Clorox on hand.
While I was at it, I redid the coax ground connection from the 160M
shunt feed. I loosened the hose clamp, sanded the #2 ground bus a bit,
replaced the single #14 wire from the coax shield with three #14's,
reapplied the clamp and tightened.
Gene Smar AD3F