Dual battery wiring question

I'm running 2 optima batteries in the bed of my 05 4.0L tacoma. I am using a perfect switch isolator one positive from the starter which is split into 2 positives (one main battery and one aux), with 2 150amp breakers (one for each battery after the isolator). There are 2 positive wires that run into the engine bay fuse box. One wire is black with blue stripe (this runs to the alternator). The other is a short black wire that ran from the + terminal of orginal battery to the factory 140amp alternator fuse. Do I need to retain this fuse even though I have 2 breakers in the bed. If I do delete this fuse will the fuse box still get power. Should have a third breaker between the alternator and the isolator. Any info will help!! If I wasn't clear please ask and I'll take photos or clarify.

My yotas dead in the water until I finish the wiring so I really appriciate the help.

Thanks Matt