Nitrate probe? Expantion modules..

[WarDaddy]

Is it possible to digitally monitor Nitrate?

I have an AC3 and would love to measure pH and Nitrate, Can I? One company sells a Noitrate probe says it can go in a ORP BNC connection.

Second question

How many expantion modules can I add to an AC3, and how many switch inputs would I max out at?

[clp]

Hi,
Currently there are not any Nitrate probes on the market that are reliable or accurate enough to be used continously in a salt water environment. When one is available we'll add support for it to our controllers.
You can add up to 7 PX 1000s to the AC3 or 3Pro. With 7 PX 1000s you would have 42 digital inputs.

Curt