- "Controls pH in both a downward and upward direction. - ???"
This means that you can connect this meter to another pice of equipment which will release chemicals into the water if the pH gets too low or too high.
" - You can select a setpoint and any range of acceptable pH around this setpoint. - ???"
I believe this means that you can select one point at which the pH will be automatically adjusted or several setpoints.
"- 110 VAC operation - ???"
Should be referring to a power supply for the system. VAC is Variable Alternating Current. This means that you can change the amperage.
"do the controller do the actual adjustment if the pH is fluctuating or do i need to plug a different device for that?"
Yes to both questions - the controller works with another device such as a calcium reactor.
"by the way, what is a probe "
Just another word for the "blue thing" that you described seeing. It is the electronic sensor that goes into the water.
"and what is downward and upward direction? "
This is referring to a drop in pH or a rise in pH . The pH scale has a range of 0 tp 14. 0 is very acidic, 7 is neutral, and 14 is very alkaline. Marine aquariums should be around 8.2. If pH falls below 8.2, the water chemistry will need to be adjusted upwards .
" hope you could help me with this 1, because i'm a newbie in this hobby.. thanks!
Hope this helps. JG