carboplus: only one week

hi,

Since a month now, I've been using a carboplus installation in my 95gallon
tank.

It seems to run fine and plants really grow fast. One (major) problem
though: after one week of working (only during the days, but always at full
blast) the units gives a red light. This probably means the carbonplate
doesn't make a good contact to the connecting piece of metal. In fact after
two weeks the piece of metal was corroded so intensively, that it stopped
working completely.
Then, I changed it with a new metal, and after a week, the new metal also
fails to give enough contact to allow the unit to work at 100%. The unit
automatically turns itself down to approx 20 or 30 %.

What can causing this effect?

Could it be that the unit can't handle 100% over longer periods (although
one week isn't very long, is it?). If so, can I bring it back to the shop,
because this product doesn't work as it promisses to do?

thanx for all your advice!!!

teizman