Nice discussion going here. Lets see...
Flowmeter, have one farther upstream in the system, it's hard to get it to be super accurate. Also, there's too many variables between the meter and the tank. There's a balast tank (can overflow if valve is closed, pump fails, human error, filters that get changed (-4 gallons every time) etc.
Load cells. Each tank has 10 legs, and goes through a concrete wall. So, the concrete would have to be chipped away considerably, and 5 load cells on each tank? That seems to me it would become cost prohibitive quite quickly.
We actually have some Anderson Instrument temperature recorders, they make alot of dairy/food/pharmecutical stuff. Good stuff, a tad pricey. I'll be talking to a dealer this week that carries Anderson, I'll see what he can come up with.
What about this company?
http://www.automatedsonix.com/level_sensors.htm
I am unsure of how fancy these devices need to be, there are alot of options out there, alot with their own calibration and computation functions allready, something I don't think I need, as the PLC can do all that.
