Can't really say, from a distance and without additional info... but if your
current bank is 3X flooded
batteries of the same basic size, shape, capacity... then the
Victron AGM version should
work fine.
If your
battery charger is "modern" enough to offer different
charging profiles for flooded, AGM, gel... then you probabbly can just choose an AGM setting and be happy. A more throughout approach would be to look up Victron's recommended bulk/absorption and float voltages, and then set the
charger as close to that as possible.
Otherwise,
charging profiles for flooded batteries are probably OK for AGMs, too. (At least that's what our slightly older charger manual recommends; it only offers two settings, one for flooded/AGM and one for gel.)
-Chris