Yes, it makes sense to me. Hopefully you'll get some suggestions from others here on signaling systems for your application. If I was looking at this project, I'd be asking the following questions about the trip-signal itself:
1) Does the pressure plate actually move measurably when the salt blocks are gone? - Yes
2) What sensing device (if any) monitors the pressure on the plate (load cell, or whatever), and if one is not there, should there be one. (That would not only tell me, if the signal from the load cell is monitored, not only when the salt blocks are gone, but when they would be about ready to disappear). - It will be a switch system, with only a present/missing report on it when the salt falls below the measured level. Happy for other suggestions, but trying to keep it simple, as I am not experienced?
3) If there is presently a simple switch that trips when the release point is reached, can I use that switch activation as a signal to my monitoring system. And if there isn't one, should there be one, like a simple lever-action trip switch. - Will be a level/switch system and then that will trigger a signal being sent to an app on mobile phones
4) Do you have easy access to the holding container for the salt blocks, or access to the pressure plate itself if it's not an integral part of the salt block container itself. - Yes, its a lid top that just slots on with gravity holding it in place. This will need to be a thin wire system, to keep it connected, unless it anything wireless can be suggested?
5) Will whatever senses the release pressure need to be manually reset or replaced each time. Or can something like a lever-activated switch under the pressure plate automatically reset itself. - It will be set when salt is added. The salt is in a heavy block form, so the pressure of the salt being present will switch the switch to showing salt present. When it ( Salt dissolves from the bottom, as water erodes it from the bottom ) falls below the monitored level, the pressure will be released (spring loaded) and a signal will be sent up to the main circuit board to inform the owner.
6) Is there salt dust or debris that can get under the pressure plate and inhibit pressure plate activation or deactivation. - o, the block salt does not have any loose salt, its a clean system.
You probably already know the answers to the above questions, I'm just mentioning them in case it offers you any ideas about how to monitor pressure plate release. THEN, somebody will probably offer you some ideas about transmitting a signal to a cell phone to let you need the container needs attention.