PID
@Ramasule - I'm pretty sure this is possible with the current stuff, wouldn't it be? It takes a bit of programming , but you should be able to set up things like (sudo code) "if <unit> is less than <value>, then turn on dosing pump for <volume/time>". That would give you a simple proportional control. You could, in theory, hook up a larger (or multiple) dosing pumps and have the same type of code trigger that (or both) instead - which would give you some derivative control. The integral control is a bit more difficult to achieve without a memory store (database). Does Apex code have access to the history of a sensor?
To be honest, our reefs should be stable enough that a PID seems like an overkill to me. Just a simple proportional control (eg; bit of code) should work for most things. I suppose you would want to ensure that the dosing pump only came on if it's not been on in a certain amount of time (to allow the addition to circulate), but I
think that's possible to do as well...
Anywho; sorry for the divergence
@Terence. Tank is looking great and the growth comparison is fun to see. Your picture has given me an idea of what to get with a soon-to-expire gift certificate from
@MarineDepot... ;-)