How To Set Up a Neptune Systems DOS for Automatic Water Changes
Water changes are one of the most important things you can do for a healthy reef tank, but they are also one of the easiest tasks to put off. They help export nutrients, replenish some trace elements, and remove undetected contaminants that can build up over time. The problem is that traditional water changes can be messy, time consuming, and easy to skip when life gets busy.
By using a Neptune Systems DŌS or DŌS QuietDrive, you can automate small, consistent water changes that happen throughout the day with very little effort from you. More stable water chemistry, fewer maintenance headaches, and a routine you'll actually stick to are all things we can get behind.
In this guide, we'll walk through how to set up a Neptune Systems DŌS QuietDrive (QD) for automatic water changes using Apex Fusion. The setup process is exactly the same for both the original DŌS and the DŌS QD, so whichever version you have, you're in the right place!
What You Need to Get Started
Required Components
Compatibility Note: DŌS is compatible with all A1 through current A3 series Apex controllers. DŌS QD is compatible with A2 and A3 series Apex controllers.
Optional Accessories
There are a few additional things that can make setup easier and safer long-term:
Preparing Your Setup for Automatic Water Changes
Step 1: Calibrate Your DŌS Pump Heads
Calibration ensures that your DŌS is removing and adding the same amount of water simultaneously and helps prevent gradual salinity swings over time.
Just hit the "Tasks" icon in Apex Fusion (clipboard icon) and click the "DŌS Calibration" option and it'll walk you through it all.
Step 2: Set Up Your Clean/Dirty Water Reservoirs
The DŌS will need a source of clean saltwater and somewhere to put the dirty tank water.
Clean Water Reservoir: Depending on the volume of your water changes, you could use a 5 gallon bucket, Brute trash can, or a larger polyethylene water storage tank.
Dirty Water Reservoir: Use a dirty water reservoir that is at least the size of your clean water reservoir, or larger. If you have access to a drain, that's even better. We like to run the dirty water tube right to a utility sink to save on space and lessen maintenance as we won't have a dirty water reservoir to empty later.
Tip: Consider using float switches connected to your Apex so that the Apex can stop AWC if your clean water reservoir is empty or if your dirty water reservoir is full.
Step 3: Run the Tubing To and From the DŌS
When you're done, you'll have four runs of tubing that look something like this:
Tip: Label the tubing near the DŌS head so you can easily tell which tube should go where. This is especially helpful later when you're swapping dosing heads or doing other maintenance.
Left DŌS Head: Clean Water
- Run tubing from your clean saltwater reservoir to the left fitting on the left DŌS head.
- Run tubing from the right fitting on the left DŌS head to your aquarium or sump.
Right DŌS Head: Dirty Water
- Run tubing from your aquarium or sump to the left fitting on the right DŌS head.
- Run tubing from the right fitting on the right DŌS head to your wastewater container or drain.
IMPORTANT: The DŌS heads spin in a different direction when in AWC mode, so make sure you follow the setup outlined above for AWC as it is different from how we'd set up the DŌS for additive dosing.
Step 4: Fill Your Clean Saltwater Reservoir
Mix up a batch of saltwater in your clean saltwater reservoir. Because we're changing such a small amount of water at a time, a heater usually isn't necessary, but having a small circulation pump at the bottom of the reservoir can be helpful for making sure the salt is mixed thoroughly.
Setting It Up In Apex Fusion
Step 1: Start the DŌS AWC Task
In the Apex Fusion app, click on the "Tasks" icon (clipboard) and click the "DŌS Automatic Water Change" option.
You'll first see a tubing diagram. Take a moment to double check that you've connected the tubing correctly.
Assuming you've completed the previous setup preparation steps and your clean saltwater reservoir is filled, press the "Next" button.
Step 2: Select Your DŌS
If you have multiple DŌS pumps, you'll want to make sure you select the right one. Click on it and it'll move you to the next step.
Step 3 & 4: Rename Your DŌS Pump Heads
First, you'll be prompted to rename the left pump head.
Next, you'll be prompted to rename the right pump head.
Step 5: Select Daily Water Change Volume
Here, you'll enter:
- Units of Measure
- Volume You Want Changed Daily
- Start/End Time for Each Day's Automatic Water Change
Step 6: Review Setup & Prime the Lines
This step in the DŌS AWC setup task is simply a recap of the information you've entered.
Make sure everything looks correct, then click "Send" to officially configure the DŌS for AWC.
Prime the Lines
Hold the "L" button on the DŌS to prime the clean water line. Keep holding this button until water starts dripping into your tank or sump.
You don't necessarily need to prime the waste side dosing head, but you can do so to inspect for any leaks or unexpected issues.
Frequently Asked Questions
What is an Automatic Water Change (AWC)?
When using a dosing pump as an automatic water change system, water is removed and added to the tank or sump at the same time, so there is no change to the water level. In reality, it's more like a water exchange.
It's usually set up to remove smaller amounts of water throughout the day vs a single big water change once a week or once a month that we'd do manually. These smaller, but more frequent water changes have the added benefit of helping to maintain stable water chemistry, reducing the see-saw spikes and valleys of water parameters.
What is the Neptune Systems DŌS?
For those that are just starting the research phase of looking into automatic water change systems, the DŌS is a dual-head dosing pump for the Neptune Systems Apex aquarium controller.
It's most often used for precisely dosing additives like calcium and alkalinity, but has become extremely popular for AWC setups in the last few years thanks to easy setup in Apex Fusion and integration with the Apex controller ecosystem.
DŌS vs. DŌS QuietDrive (QD): What's the Difference?
The steps in this guide will apply to both the DŌS and DŌS QD; setup is exactly the same.
The QuietDrive version is the newer of the two and utilizes technology first seen in EcoTech Marine devices that makes the QD significantly quieter. This is a welcome upgrade when it comes to AWC setups as the dosing heads are moving quickly and generally produce more noise vs lower-volume two-part dosing.
How Often Will I Need to Change the DŌS Dosing Heads?
How often you'll need to swap out the dosing heads will be highly dependent on how volume they're moving.
Because we don't want to be changing these out after a failure, a good rule of thumb would be to replace them about once per year when using the DŌS for automatic water changes. For lower volume additive dosing, the pump head lifespan is significantly longer.
How Often Will I Need to Refill the Clean Saltwater Reservoir?
This depends on the size of the reservoir and water change volume.
We usually like to use a reservoir that can hold about a month's worth of clean saltwater.
Do I Need to Heat the Water for My Automatic Water Changes?
Typically, no.
Because the DŌS is adding and removing small amounts of water over the course of many hours, room-temperature saltwater won't cause a noticeable temperature drop in your aquarium.
Can I Use Standard RO Tubing Instead of the Provided DŌS Tubing?
Yes!
This is actually how we have most of our DŌS AWC systems set up here. It's a tight fit, but you can push standard 1/4" RO tubing onto the DŌS heads with some gentle force.
Alternatively, you can use a 1/8" female thread x 1/4" push connect adapter to convert your DŌS to accept 1/4" RO tubing more easily.
Adam has been reef keeping since 2010 and got his start on the Bulk Reef Supply Customer Service team. He believes the best tanks are built around what you enjoy, not what’s trending. Adam is especially interested in simplifying the hobby, exploring the latest gear, and helping others focus on long-term success over chasing perfection.
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