Meters & Controllers
meters & controllers — pre-owned
Browse 260 meters & controllers — pre-owned on eBay — listings updated every few minutes. All items are pre-owned and sold by eBay sellers directly.

Neptune Systems Apex Energy Bar 832 EB832 Excellent Condition
The Neptune Systems Apex Energy Bar 832 EB832 is a high-quality meter and controller designed for fish and aquarium enthusiasts. With its advanced technology and reliable brand reputation, this energy bar provides essential monitoring and control functions for maintaining optimal conditions in your aquatic setup. The sleek design and precise measurements make it a crucial component for keeping your fish and aquatic plants healthy and thriving.

Neptune Systems Apex Jr Aqua Controller
The Neptune Systems Apex Jr Aqua Controller is a digital controller designed for aquarium enthusiasts. This unit, from the trusted brand Neptune Systems, is capable of measuring and controlling water temperature for all water types. With its compact design and specific focus on temperature management, it is a valuable addition to any fish tank setup. Whether you are a beginner or a seasoned aquarist, the Apex Jr Aqua Controller offers convenience and precision in maintaining the optimal environment for your aquatic pets.

Profilux Plus II controller with Salinity Card w/ Power Cord
The Profilux Plus II controller with Salinity Card is designed to measure and control salinity levels in aquariums. This controller is specifically meant for monitoring and maintaining the salinity of the water in fish tanks. It falls under the category of Meters & Controllers, making it an essential tool for fish and aquarium enthusiasts looking to ensure optimal conditions for their aquatic pets.

Adaptive Reef - 6 Way Apex Switch Toggle Box- used
The Adaptive Reef 6 Way Apex Switch Toggle Box is a unit designed for marine aquariums, specifically for controlling multiple devices or pumps in a reef tank setup. Made by the brand Adaptive Reef in the United States, this switch toggle box offers a convenient and organized way to manage various functions in a marine environment. With 6 way apex switch capabilities, this product provides flexibility and ease of use for aquarists looking to simplify their tank management system.

Neptune Systems Apex Energy Bar 832 EB832 Excellent Condition lot bundle
The Neptune Systems Apex Energy Bar 832 EB832 is a high-quality controller unit designed specifically for fish and aquarium enthusiasts. Produced by the reputable brand Neptune Systems, this model offers advanced technology and features to effectively manage and maintain the energy needs of your aquatic system. Its excellent condition ensures that it is in top working order, making it a valuable addition to any aquarium setup.  pulled from a working environment please view pictures carefully to see what items are included

Neptune apex system pro head unit A2 pro . Excellent conditon. Probes included
Neptune apex system pro head unit A2 pro. Probes included. From running system.

Neptune Systems Apex Lab Grade Salinity - Conductivity Probe MFG 2016
Used probe but still works good. Includes calibration solution and the probe will need to be re-calibrated.

Red Sea ReefATO+ Digital Water Level Controller Automatic Top-Off Aquarium
Used Red Sea reef ato for existing setup. Does not includes mounts or holder for sensors. Tested and working.

Hanna Instruments Marine Salinity Tester HI98319 Blue/White- Light Use
Excellent condition with minimal signs of use.

Neptune Systems - PMUP v2 Practical Multi-Purpose Utility Pump (PRE-OWNED)
Functionality: Fully functional, includes all essential & accessory components to function properly. May have multiple units available - inquire to check for availability! Condition: Item shows minor signs of use (e.g., slight wear marks).

Neptune Systems Apex Energy Bar 832 Model No. EB832 with AquaBus USB Cable
Neptune Systems Apex Energy Bar 832 Model No. EB832 with AquaBus USB Cable. The Neptune Systems Apex Energy Bar 832 is pre-owned and in great f unctional condition. The protective outer sheath near the cable entry is slightly worn, but the internal wiring remains intact and fully functional.

Used Neptune Systems Apex Temperature Probe Temp
Used probe but still works good. Condition may vary

Neptune Systems Apex Energy Bar 832 Model No. EB832 w/ (8) 2-Foot Extension Cord
Neptune Systems Apex Energy Bar 832 Model No. EB832 with (8) 2-Foot Extension Cord. We take great pride in properly representing each item that we have for sale.

Neptune Apex Flow Sensors - 3 Piece Lot
The Neptune Apex Flow Sensors 3 Piece Lot is a set of high-quality flow sensors designed for fish tanks and aquariums. Made by the reputable brand Neptune, these sensors provide accurate and reliable measurements of water flow in your aquarium system. This lot includes three pieces, allowing you to monitor multiple areas in your tank for optimal water circulation and filtration. Ideal for aquarists looking to maintain a healthy and efficient aquatic environment, these flow sensors offer convenience and peace of mind. Listing is for all 3 pictured

1 Neptune Systems Apex Fluid Monitoring Module FMM
Neptune Systems APEX FMM Module, Used in good working condition. Shipped with USPS Ground Advantage.

Pre Own Focustronic Mastertronic Automated Water Tester. Price reduce $950.
Dosetronic Compatible: Yes. Socket Communication: Yes. Easy-to-use iOS and Android App. Standalone: Yes. Software: iOS app, Android app, wifi based. Connectivity: Cloud, App. dKH: 0.1 dKH / 0.05 dKH.

Aquatek CO2 Regulator with Integrated Solenoid For Paintball or Fish Tank
The compact space-saving design of Aquatek CO2 Regulator with integrated Solenoid Valve for Paintball Tank is ideal for smaller set-up of CO2 systems. All in one unit is perfect for calcium reactor and freshwater plant CO2 injection applications.

Neptune Systems Apex Lab Grade Salinity - Conductivity Probe MFG 2017
Used probe but still works good. Includes calibration solution and the probe will need to be re-calibrated.

Hanna Instruments Aquarium / Marine Digital Handheld Colorimeter - Lot of 5
Aquarium / Marine. Marine calcium. Marine phosphorus. Marine phosphate. Marine nitrate.

Ecotech Backup Battery "AS IS" For parts/Repair
We have a Ecotech Backup Battery "AS IS" For parts/Repair. It comes as pictured with nothing else included.

American Marine PINPOINT PH MONITOR ONLY NO PROBE TESTED WORKS
The American Marine PINPOINT PH MONITOR is a digital pH electrode specifically designed for marine water testing. This product does not include a probe, but has been tested and confirmed to work effectively for monitoring pH levels in fish tanks and aquariums. With its reliable brand and accurate measurements, this tool is essential for maintaining optimal water conditions for marine life.
You save $2.00

Milwaukee MC122 PRO pH Controller With Dosing Pump - NO PH PROBE
Milwaukee MC122 PRO pH Controller With Dosing Pump - NO PH PROBE. In good working condition, but does not come with PH probe.

Neptune Systems Apex DOS Dosing & DDR Dosing Reservoir w/ Power Adapter AquaBus
The Neptune Systems Apex DOS and DDR Dosing Reservoir is pre-owned and good functional condition. We take great pride in properly representing each item that we have for sale.

Neptune Systems Apex PMK Par Monitoring Kit. ASM Module
Used neptune systems par monitoring kit. Has been tested and works good without any issues

Neptune Systems Apex A2 Base Unit Only with Thermometer pH ORP Salinity & Holder
The Neptune Systems Apex A2 Base Unit, Probes, and MPR Magnetic Probe Rack is pre-owned and in good functional condition. We take great pride in properly representing each item that we have for sale.

Neptune Systems Trident Reef Marine Aquarium Water Analyzer w/ 1Link Cable
Neptune Systems Trident Reef Marine Aquarium Water Analyzer with 1Link Cable and 3D Printed Needle Guide. The unit was properly shut down prior to storage. We take great pride in properly representing each item that we have for sale.

Neptune Dosing System. Doser. Excellent condition
The Neptune Systems DOS is an advanced, dual-head peristaltic dosing and fluid metering system designed for marine aquariums, featuring seamless integration with the Neptune Apex controller via Apex Fusion. It uses precise stepper motors for high-accuracy dosing (0.1 ml to 250 ml/min) and automatic water changes, while utilizing QuietDrive technology for silent operation.

Milwaukee MC122 pH Controller With Dosing Pump - NO PH PROBE
Milwaukee MC122 pH Controller With Dosing Pump - NO PH PROBE. In good working condition, but does not come with PH probe.

Neptune Systems A3 Apex
Apex Neptune A3 Base model. No probes but I do have the cords for it. Ports are clean and ready to go!

Neptune Systems Apex Dos
Used apex DDos. Never had any issues with it. Used it for calcium and alk

Neptune Systems Apex Energy Bar 832 Model No. EB832 with AquaBus USB Cable
Apex Energy bar works great except orange LED indicator lights no longer work. Doesn’t affect functionality at all.

Neptune Systems APEXEL Base Unit Digital Aquarium Controller with pH Probe
Probes have been kept out of water and should still function properly. Unit powers on; no issues observed, though full calibration may be recommended before use.

Apogee MQ-510 Underwater PAR Meter w/ Sensor + 38” Telescoping Pole – Excellent
Excellent condition. Fully tested with no issues. Sensor has minimal underwater use (~20 minutes total). Underwater quantum sensor (attached). Excellent condition with minimal signs of use. Clean and well maintained.

Neptune Apex A3 Pro With Liquid Level Sensor, Temp Probe
Used apex a3 pro with liquid level sensor, and temp probe. Only comes with what’s in the photos.

Kactolly Smart Pool Tank Water Testing Monitor Only
Pre-owned, in great working condition, nice and clean.
You save $9.60

JBJ Automatic Top Off (ATO) System - Water Level Controller with Pump & Sensor
Complete and ready-to-use JBJ ATO system. Float Sensor with Snail Guard and mounting bracket. Power Adapter.

Neptune Systems Apex PM1 pH/ORP Probe Module W temp Probe
Add extra pH and Temp monitoring onto your Apex system. Includes Temp probe.

Hanna Instruments HI772 Digital Handheld Colorimeter Marine Alkalinity Test Kit
Hanna Marine Alkalinity (dKH) Checker (HI772). I do my best to represent the item as clearly as possible. Still Has screen protector. Range: 0.0 to 20.0 dKH.

hanna instrument HI 96724 Portable Photometer
Vendo fonometro per analisi precisa dell'acqua per piscina o sistemi di trattamento acque.

Pearl Kogyo ZDK-916L2C-P Tuner Controller
Pearl Kogyo ZDK-916L2C-P Tuner Controller
You save $269.40