Well, unlike you I DID NOT know that until I actually tried to buy one myself :wink:

One of the few thing I remembered from school, that and how to sneak out of the school and not get caught to go well let's just say......................get happy.:biggrin:

Ok so I think I have it figured with some inlightenment from Kien. Here is what I might look into.

Neptune Systems Apex Lite Controller Package:

-Package includes: Apex Lite Base Unit, Apex Display Module, Temperature Probe, and Energy Bar 8 Module.

And add on:
- Conductivity Probe
- pH Probe - Lab Grade
- ORP Probe - Lab Grade

Any other suggestion for add-ons

did you figure out what the orp probe is yet?

Not 100% but I think it could stand for Oxidation Reduction Potential. :noidea:

oh ok :redface:

The standard package and unit won't allow you to measure salinity. To monitor salinity, you need to buy the probe ($130 ) and the PM2 module ($92)

Also The Apex base unit supports 3 probes. (Temp, pH, and pH/ORP). The Apex. Lite only supports 2 (Temp, pH)

Make the orp probe the last you add. There is much debate about what orp can really tell you. It certainly is not as easy as "orp should be X". When it drops, it suggests that something has changed, but you don't know what.
You can manipulate/control orp with ozone, bit even that can be tricky because the orp readings can be normally erratic.

Hey Tai, thanks for jumping in here.

So can I add the PM2 to the Apex lite? That would give me 2 probes on the base unit and 2 on the PM2. Is the ORP probe a must have?

You only really need the ORP probe if you are going to run Ozone. The probe will control your ozone generator so that you can set up a parameter and have the Apex keep the reading steady. Also you only really need 2 pH probes if you are running a Calcium reactor. 1 probe for tank pH and one for reactor effluent pH. Same thing as the ozone, the apex will control the co2 solenoid based on the effluent pH you set it up for. The only other thing i would suggest getting is called the breakout box. You can hook up 6 electronic float valves or water sensors. Good for controlling ATO, sump levels, flood detection, RODI, etc. I am going to try to pick one up for my Apex along with another EB8 as I have found I ran out of outlets.