I apologize for the following elementary questions, but the last time I saw a non-maintenance-free battery was in the 1960s and they didn't look like the ones installed on the sump pump.
Each battery has two rectangular caps. I asume that both are to be pried-off and cell chambers are underneath?
The batteries are on a 24/7 charger which goes into trickle mode when battery is fully charged. Should the charger be temporarily unplugged when checking fluid level? In other words, is there additional risk when checking the fluid level while charger is connected and running? Thanx, Jack