I looked into the HydroCaps, from my battery wholesaler.

I seem to remember that the price was about $12 each. (4batt. X 3cells X $12
= $144)

If the price wasn't enough to turn me off, the fact that these things are
about 3 inches tall, above the battery top.. I just didn't have the room for
them since the batteries were already 17 inches tall.

BTW. I finally filled my batteries yesterday and it too a gallon of water
($.58/gal) and this was after one year in service with 3 months of heavy use
this summer. A gallon may seem like a lot of water, but these batteries
(L-16) have a lot of volume above the plates. So it was about 11 oz. per
cell.

Steve
s/v Good Intentions