Shop Neptune Systems DOS
  1. DDR DOS Dual Reservoir
    Neptune Systems
    DDR DOS Dual Reservoir

  2. DOS Replacement Pump Head
    Neptune Systems
    DOS Replacement Pump Head


How far can the Neptune Systems DOS pump?

  • Vertically: Maximum of 24ft in any combination. The pump can be at the bottom, middle, or top of that vertical distance.
  • Horizontally: Maximum of 100ft. in any combination. The pump can be at the start, middle, or end of that horizontal run.

What size is the Neptune Systems DOS tubing?

The DOS fittings are designed to accept 1/4" inner diameter tubing. They tapered fittings with locking collars securely hold the tubing in place minimizing the risk of leaking or air being drawn into the line. You can use soft silicone, vinyl, or even rigid RO tubing without issue.

How is the Neptune Systems DOS set up?

Follow the get started guide included with your DOS which essentially involves attaching it to your Apex and connecting the tubing.


  1. Open up Apex Fusion
  2. Click on the clipboard for Tasks
  3. Select "DOS Calibration
  4. Follow the step-by-step instructions for initial calibration. 

From here, you can choose from one of three additional tasks to set up your pump accordingly: DOS Additive Dosing, DOS Automatic Water Changes, or DOS Manual Water Change.

How do you calibrate a Neptune Systems DOS?

Just follow the same calibration process using the Fusion Tasks outlined above. You will need to have two cups, the included graduated cylinder, and some water to complete the calibration process. There are only 7 steps and it will take no more than 10 minutes to complete the calibration of both pumps.

Does the Neptune Systems DOS work with the Apex Classic?

Yes, the DOS is compatible with all Apex controllers including the Classic, Lite, Jr., and EL.