Will I need a different onboard charger?

Thinking about going from two Interstate SRM29 12v batteries to two Trojan T105 6v batteries for the stereo bank. Currently using a Pro Mariner Prosport 120 on the stereo bank (got another small charger for the starting battery). Will I need to upgrade my Prosport 120 to another charger being that I'm going to just about double my amp hours? Thanks for the replies.

A charger with more amp output will work far less harder then the 12.

AJ,
With seriesed batteries you do not sum the amp/hours as you would in parallel (instead you sum the voltage). So at 225 A/Hs, you would want a 20 amp charger minimum and a 30 amp charger maximum. This range will correctly condition the batteries and do so safely. If you have a 30 amp charger, that is distribute on demand, a 'smart' multistage, and two bank, then this can service your starting bank also. I would keep the starting battery a flooded type as well. I would get with Odin at Earmark as he has a good 30 amp charger solution. Generally in a 30 amp class, most everything is 3-bank but you'll use only two banks.