The only alarms I recall on the system monitor was for engine coolant temp. You can have no raw water for a bit before that alarm goes off. If you put a Borel just downstream of the shower you will get an alarm before the engine overheats. Highly recommend.
I know most of you are experienced divers, but without any training this system could be hazardous to your health. I hope they are informing customers of some basics about breathing under water.
Long time ago I owned a twin beech D18. I hauled a group of advanced sky divers on a regular basis. Many said they had hundreds of takeoffs but no airplane landings. Point of pride for them.