Your valves are Valterra type slice valves:


When the handle is UP, they're open; when it's DOWN, they're closed. Do NOT close these valves suddenly, when the pump is on: you can break something! Also, they are not very good at throttling; they're either open or closed.

Checking on the Aqua Smarte; it appears to be an older version of the King Tech 'mineral pak' thing, where 'mineral' = copper. A manual for the current model is here:
http://www.kingtechnology.com/pdf/ma...al-English.pdf

This parts list may apply:
http://www.kingtechnology.com/pdf/parts/Parts-AG.pdf

I'd plan to replumb and remove that beast, when you get a chance -- it can definitely restrict flow.

Open it, and remove any cartridge inside and re-close it.