2002 Gem e825 2 seats- switching from Gel to AMG Batteries

I have a 2002 Gem e825 2 seats and I just purchased AMG batteries to replace the gel batteries. How do I switch the charger setting from gel to AMG?

72v Gem chargers don’t support agm.

Really! There’s a setting for Gel batteries. Is there no setting for AGM? The batteries called for is:
Trojan 30XHS 12 V Group 31. The AGM was comparable.

You will ruin the new batteries without the right algorithm. GEM limited the number of algorithms installed in the OEM QuikQ chargers. Your only solution is to either return the AGM for the FLA Trojans or GEL Type (and set charger to correct algorithm), or swap out charger for one with the right algorithm. There are a number of folks on this site who can help with that alternative.

That is my understanding.
@Old_Houseboater suggests using the flooded setting for agm.
Else you will need charger reprogrammed.