ESS dynamic cut-off voltage for flooded lead acid batteries

I have 5 x 12V 130Aah flooded lead acid deep discharge leisure batteries connected in parallel to a MultiPlus 12/500.

The multi is ruining an ESS assist. Pleas could someone advise me as to the most appropriate cut-off voltage settings to enter in to the ESS assistant settings for my flooded lead acid batteries?

I am currently getting low battery warning messages when the inverter AC output exceeds approximately 290 watts.

The cable connecting the batteries to the Multi has a CSA of 50 square mm.