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Neptune Systems Apex AquaController PM1 pH or ORP, Temperature, I/O Expansion Box


Item #: NS3331

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The first expansion module, the PM1, with a pH or ORP, temperature, and 6 digital inputs.

4 in 1 goodness with this module!

The PM1 probe module is just what you need if you want to monitor pH or ORP in your tank. And, there is an added bonus, you get an extra temperature port as well as six I/O switch inputs for use on ATO, feed buttons, leak alarms or whatever else you may come up with. (I/O Break Out Box required).

This module is perfect for someone that wants to add an additional pH or ORP port to their Apex System.

Great uses for the extra ports

If this is an additional pH port, it could be used for another tank or for control of the CO2 solenoid on your calcium reactor.

If you choose to use it for ORP, you could have the Apex use that ORP value to turn on and off an ozone generator.

Of course, you could set up audible or email alerts too if these values should fall out of range.

Extra Temperature port

Having an extra temperature port and probe is always useful. Some people like to put one probe in the display tank and one in the sump just for redundancy. That way, should your return pump go out, you would be monitoring the display tank and would see the temperature falling and know something was not right.

Want to monitor an additional tank?

With the PM1 you can easily use your existing Apex to monitor additional tanks simply buy adding this module. Then, just buy our pH and Temperature probes and you’ll be all set!

Six I/O Switch Ports

Purchase the optional I/O Breakout Box and you can monitor the off/on state of six I/O signals. This is useful if you want to set up an ATO (Auto Top Off), a feed button, or even a sump door alarm or light switch.

  • Monitor/Control pH or ORP, and temperature.
  • 6 digital inputs for float switches, water on floor sensors, pressure sensors, etc. (I/O Break Out Box required)
  • Full datalogging support in Apex Base module.
  • Up to 240 AquaBus modules can be added to the Apex and Apex Lite system (5 for Apex Jr).
  • Plug and Play. Automatically recognized when installed into the system.
  • Two AquaBus connectors for flexible expansion via AquaBus
  • Led Status Indicator
  • Upgradeable firmware.
  • Compatible with Apex, Apex Lite and Apex Jr. systems.
  • Galvanic Isolation for accurate and reliable probe readings.
  • Comes with 3` AquaBus cable.

Manufacturer information

Neptune Systems Aquarium Supplies
Neptune Systems is one of the world’s leading manufacturers of aquarium controllers. The company was founded in 1995 for the purpose of developing affordable water quality monitoring and control instrumentation. Their engineering team has extensive expertise in computer hardware and software system design as well as a background in water quality analysis. Neptune Systems uses these finely-honed engineering skills to develop innovative monitoring and control solutions for use in reef and fresh water aquariums, aquaculture tanks, hydroponics systems and general laboratory use. Neptune Systems is best known for their AquaController line. The company is known for their innovation and customer centricity.

5 Stars


Reviewed on
December 03, 2019

Yes, I would recommend this.

Good addition

Pros: Easy installation

Cons: None

I bought one in order to add another ph probe. It's been working with any problems ever since. Not so pricey compared to other modules.

Was this review helpful? 1 0


Reviewed on
August 06, 2017

No, I would not recommend this.

Another module?

Pros: It works

Cons: Yet another module........

Every peice needs is own module, but they all let you add "another temp probe". Thought this was all I would need. It's not.

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Reviewed on
February 14, 2017

Yes, I would recommend this.

Excellent Product

I own two of these modules that i use to monitor the pH of my calcium reactor and tank pH. I use the Double Junction probes for both. I run them off an Apex Jr. I swore up and down for years I would never waste money on a controller. ITS BEEN ONE OF THE BEST PURCHASES FOR MY REEF TANK! I love being able to see the graphs of my tank parameters on the fusion website.

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eric buzzelli

Reviewed on
January 19, 2014

Yes, I would recommend this.

Very happy

I already have an established apex system on my main system. For Christmas my daughter begged me for her own tank in her room. So, Santa brought her a innovative marine Nuvo 8 (bought here). It is setup as a fish only saltwater tank with live rock. I couldn't see myself going backwards with analog or digital timers and I wasn't a fan of having another console with a full apex deployment. So, pm1 and a little snaking of a 100ft apex cable through my attic and presto. Full monitoring and control of my nano. Yeah I know it is overkill, but isn't most of the stuff we do with this hobby?

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gary lowe

Reviewed on
May 11, 2012

Yes, I would recommend this.

Love it

I have been having issues with several corals in my reef tank for months now. They were only happy occasionally and I could not figure out exactly why. Come to find out I was unable to distinguish the colors on my pH test kit. After installing the PM1 With a pH probe it was obvious that I have chronic low pH and that was causing my corals to not to thrive like they are now. After only 5 days it's amazing the difference now that I am keeping my PH where it should be. NOTE 2 other older guys: our eyes ain't what they used to be! I love this product and I wish I would have bought it months ago.

Was this review helpful? 0 1

tom smith

Reviewed on
March 31, 2012

Yes, I would recommend this.

Works as advertised

Great product... Documentation was good, but it should have just told you to use the web interface to calibrate it...Don't forget to buy the actual probe you want to monitor... Customer Service did a nice job getting me squared away, after I forgot the probe.... :)

Was this review helpful? 2 0

nathan peters

Reviewed on
September 09, 2011

Yes, I would recommend this.

Bought PM1 for my APEX Jr.

I recently added this unit to my Apex Jr. (I'm loving the Apex Jr. and I purchased it without the display). I was a bit concerned about the PM1 working with my setup when I first read the directions. It says in the directions that the PM1 cannot activate a pH probe in the web interface, which is all I have! THAT IS NOT TRUE! I wrote Neptune systems and they assured me it could be done in the web interface and that you didn't need the Apex display unit. Sure enough I received my PM1 module, calibrated and activated the pH probe in the web interface and never needed the Apex display. I'm loving the unit and it is very helpful for me now to track on a graph in the Apex Jr. the daily fluctuations of my pH. Also it can adjust pH for temperature, though I haven't used that yet. Would definitely recommend to anyone that wants to track pH!! 4.5 stars because of the out of date instructions and because the unit requires that all probes be purchased separately.

Was this review helpful? 7 0

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