With so many additives that are hitting the market today, that focus on biological nutrient removal can easily and rapidly take up the dissolved oxygen in the tank leaving it very hard or nearly impossible for your fish and corals to breathe. If you employ any bacterial nutrient control system like biopellets, carbon dosing, or nitrate reactors it is a wise investment to purchase the PM3 and dissolved oxygen probe.

Dissolved oxygen is one of the most critical components to a healthy, thriving tank, but is commonly looked over due to the probes high price tag. Once the probe is purchased it can last a lifetime with the straightforward and easily replaceable membrane that is usually less than 10 dollars to replace. When it comes to probes, you get what you pay for, and Neptune has sourced one of the best lab grade dissolved oxygen probes available today.

The PM3 module also has a bonus that it comes with an open port for a temperature probe and also another opening for an I/O switch port that would be used with the breakout box for monitoring float switches, magnet switches, and much, much more.

Features:
Monitor/Control Dissolved oxygen and temperature
6 digital inputs for float switches, water on floor sensors, pressure sensors, etc
Plug and Play.� Automatically recognized when installed into the system
Two AquaBus connectors for flexible expansion via AquaBus
Comes with 3' AquaBus cable
Galvanic Isolation for accurate and reliable probe readings
LED Status Indicator
Upgradeable firmware
Compatible with all Apex systems
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Dissolved oxygen can easily be manipulated with either air pumps and air stones, aiming return nozzles at the surface of the water, or a water pump that vertically pushes the water to the surface to allow for gas exchange. In a typical reef tank, most O2 is lost and transferred with CO2 at the surface of the water.

Another large sink for dissolved oxygen to be consumed is settled detritus, food, and other dissolved organic compounds. As the process breaks down organic compounds dissolved oxygen will be consumed. For overstocked tanks that can cause a huge issue as your animals will consume the oxygen as well as their waste which could lead to dangerously low levels of dissolved oxygen.