Mon-Thurs 7am-5pm PST
Fri 7am-4pm PST

Questions about products, orders, shipping?
Contact us by call or email

Neptune DOS - Auto Water Change and Dosing System


Starting at $28/mo with . Learn more

Item #: NS98980

Free Upgraded Shipping!

In Stock

A multi-purpose dosing and fluid delivery system of uncompromising quality combined with the simplicity of Apex Fusion software wizards for operations such as:
  • 2-part dosing (Calcium and Alkalinity)
  • Other additives dosing
  • Automatic water changes
  • micro-quantity dosing
  • delivery of liquid foods and supplements
The DOS connects to any Apex via its AquaBus connection. The true versatility and functionality of the DOS comes to life via the software wizards built into Apex Fusion. This takes dosing to a whole new level in terms of ease of use as well as functionality when compared to standalone dosing systems because the DOS is part of your Apex ecosystem. Not only can you integrate it into other operations and devices you have configured, but we also will be continuing to expand on its capabilities as time goes on via software updates to Apex Fusion.
APEX Ready

2-part dosing made easy
The #1 reason people purchase a dosing system for their aquariums is for consistent and easy dosing of 2-part solutions (calcium and alkalinity) to their reef tanks. The DOS wizards in Apex Fusion take this to the next level by integrating a feedback loop from your water testing to make suggestions to fine tune the amount you dose each day. Simply put in your tank size and after a few days of entering testing results, it will help you refine your dosing amounts for the demand of your particular aquarium. No more guessing. No more fooling with the timings.

Water changes – the never ending chore of an aquarium
Hate doing water changes? – everyone does – so they never get done as often as they should. Not only that, water changes are disruptive to the stability of your system since all of that change is happening at once.

With the DOS all you do is place your empty vessel and your fresh stock of saltwater under your stand. Then, with the Apex Fusion wizard just tell it amount of water you want to change over what length of time and the hours of the day you want it to happen and it figures it all out for you. It will perform an automatic, continuous water change for you. It gets better. If you have our dual optical water sensing accessory Apex Fusion will send you an email or text message letting you know it is time to change out the jugs. Less time pumping, siphoning, and sloshing water and more time enjoying a great aquarium.

Micro-dosing of elements
If you need to dose tiny amounts of a particular solution, element or other fluid (like vodka dosing or Zeovit systems), the DOS is the perfect solution due to its precision controlled stepper motor. This ability to control pump movement in such a refined manner means that you can dose all the way down to a single drop of fluid at a time!

APEX Ready
How is it built?
When it comes to dosing, it all starts with the peristaltic pump

First, lets talk about the pump hardware. Be aware that not all dosing pumps are built alike. Well, lets clarify that. Almost all OTHER dosing pumps are alike – but most ALL OTHERS are very different from the DOS.

Nearly all dosing systems on the market today use a standard, DC brush-driven motor. Why? Because it is economical. This is the same motor you might find in your child’s toy car. We thought that was just not adequate for an aquarium where you might have thousands of dollars invested. So, we spent over a year searching and testing pumps and motors and decided on using a pumps with industrial grade stepper motors in the DOS – the same type of motors used in high end robotics, 3D printing, and medical equipment. So, why does it matter?
  • Precision - With the stepper motor pumps on the DOS, you have precise control each time you dose. And, you are guaranteed it will stay calibrated pretty much forever. On the other hand, with the standard DC motor pump found in most dosing systems, it cannot dose small quantities with ongoing accuracy and consistency. They also require ongoing calibration to account for the wear of the motor and the mechanisms. When pumps fall out of calibration, they dose either too much or too little – never a good thing considering an overdose to a tank will often be its demise.

  • Variable Pump Speeds - One of the great features of the stepper motors on the DOS pumps is that they can be driven at various speeds depending on the purpose for which they are being used. For instance, dosing of vodka may require the slowest possible rotation while a water change use requires a much higher pump speed. The best part is that Apex Fusion wizards automatically select the proper speed based on the use and because of the stepper motor, accuracy is not compromised even at the higher speeds.

  • Gearing and Drive Mechanism - The DOS uses a direct drive mechanism that will not slip, it will not strip, it will not grind to a halt. On the other hand, many other peristaltic dosing pumps used for aquariums have gears that can (and do) strip. Or, worse yet, some pumps work by using the friction of rubber rollers on the smooth metal motor shaft to make the pump spin. Foreign matter like salt creep, additives, etc. often get into the drive mechanisms of these pumps and make them fail or pump unknown amounts.

  • Lifespan - The stepper-motor in the DOS has a MTBF (mean time before failure) of 5000 hours. Other systems with brush-driven DC motor pumps have lifespans measured of just a few hundred hours of use. This means the pumps on the DOS may have up to as much as 12x the lifespan of others.
APEX Ready

Secure, Large Diameter Tubing Connections
Leak proof fittings are very important, not just because of the possibility of leaking fluid, but also because the leaking of air into a line would cause the pump not to meter the correct amounts. The pumps on the DOS have sure-fit compression fittings that are virtually leak-proof. Contrast this to other dosing systems on the market that still use dual-barbed fittings that commonly split the tubing and cause leakage of fluids or air.

Larger size tubing means that your pump does not have to work nearly as hard – or stay on for longer cycles. The most popular dosing pumps on the market use tube fittings with the tiny diameter of 1.67mm. The DOS uses much larger tubing and fittings. In fact, at 3.33mm in diameter, the pump on the DOS can handle 4x the flow of the most common pump style on the market (pictured). This means that your pump (and motor) will run 1/4 the time to pump the same amount of fluid. Less run time means less wear on the pump mechanism, tubing and motor and extends your dosing pump’s life. Larger diameter fittings also eliminate clogging – a common issue when dosing various elements like Calcium, Alkalinity, or Kalkwasser on smaller tubing pumps.
APEX Ready

Simplified Interface
Though nearly all interaction with the DOS will be done through the graphical user interface on Apex Fusion, there still is a need simplified user interface on the DOS itself. This is accomplished using a multicolor indicator for each pump to show its status as well a button to be used for priming the pump or for use during a calibration process.

Replacement Parts
Changing out the peristaltic pump tubing on the DOS is a snap. Literally! All you need to do to change out the pump tubing is squeeze the pump head and remove. Then take out the tubing, replace with a new one, and snap it back on. No screws, no impossible snap on covers and no fussy loose rollers to mess with. And, because you are not changing out an entire pump head, your costs are lower as well!

AquaBus Connection to your Apex
The DOS easily connects to your existing Apex System via an AquaBus cable. All configuration and control of your DOS is done through the Apex Fusion interface on your phone, tablet, or computer from at home or anywhere in the world! And, because there are two AquaBus connections, you can daisy-chain up to 10 DOS systems together.

Accessory port
The DOS has an accessory port that will enable it to be connected to an upcoming optional accessories like the DDR – Dual DOS Reservoir. This accessory has two separate 2-liter cylinders for holding your additives. It also has optical sensors at the bottom that tell the Apex when it is time to refill and it then can send you an email or text alert. Another optional accessory will be a set of two optical level sensors you can install in the water change vessel (jug/rubbermaid/brute) of your choice.
Quiet Operation
We understand that aquariums are supposed to be serene. And noisy pumps often ruin that mood. So our engineering team has taken extensive steps both in how the pump operates as well as the enclosure design to ensure that the DOS system is one of (if not) the quietest dosing systems on the market for the fluid volumes it delivers.

Stylish Yet Functional Design
The DOS was designed to compliment your aquarium – not just be a box that holds pumps. Its attractive enclosure has the pumps rotated at an outward angle to allow for the tubing to be routed with no chance of kinking, even when placed on a shelf. The DOS are also designed for stacking and they can be daisy-chained together via the AquaBus ports. Even when stacked, all tubing can be easily routed kink-free. For those that prefer a wall mount, the DOS has easy to use slots in the back so you can attach it to a wall or to the inside of your aquarium cabinet. With the exterior design, component selection, and software functionality, the DOS communicates how much total effort we have put into this product to raise the bar not only for dosing systems, but for premium aquarium products overall.

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
January 21, 2021

Yes, I would recommend this.

Great Doser

Pros: They are reliable and worth every penny. Very accurate and does what it is suppose to. Love the contrablity in fusion. So far I have gone 18 months on same heads and they have not lost calibration. I do check every 3 months.

Cons: When used for AWC they are extreamly noisy. Must use Apex as they are not stand alone dosers

I run 2 of these and they run flawless. 1 is used for AWC and 1 is used to dose 2 part.

Was this review helpful? 1 0


Reviewed on
April 17, 2020

Yes, I would recommend this.

Makes Water Changes EASY

Pros: Set it and forget it. Good quality.

Cons: Lack of customization options

I use this in conjunction with my APEX... one unit to dose Ca/Alk, and the other to do Auto WC's. Makes having a reef tank MUCH easier.

Was this review helpful? 0 0


Reviewed on
April 25, 2019

Yes, I would recommend this.

Great dosing/water change pump

Pros: Easy to set up and program, very controllable, stepper motors are awesome.

Cons: Pump can't be programmed to do a specific task, it has to follow the dosing procedure Neptune has set up. There's also no way to change the stepper motor speed when it's switched to ON on the Apex.

Overall, this thing is fantastic. I now finally have two of them, one has been used for 2 part dosing for a while and the second one is now set up for AWC. It's extremely accurate, easy to calibrate and set up and does an awesome job. Also, the tubing connections on it are fantastic. Being able to use airline tubing or 1/4" RO tubing and change it easily and quickly is a huge bonus that needs to be mentioned.

That said, here are the negatives that are in no way a deal breaker and I do not take a star off for:

1- On low speeds this is a very quiet dosing pump. However, on high speeds needed for AWC, it's definitely pretty loud.

2- It is not possible to tell the DOS to pump out a certain amount all at once. As in, I can't program it to just pump out a gallon of water. It has to be programmed to do this over time and it will "decide" on how much time it's going to need to pump out a certain quantity of liquid. For example, the fastest it will pump out a gallon is 50 minutes. The DOS will run the pump at 250ml/min 3 times over that 50 minutes and will pump 1/3 gallon at a time.

3- There is no way to change how fast the DOS will run the pump if it's just set to ON on the Apex. It will always default to a set speed of about 25ml/min. It will also automatically stop for an hour after it doses 200ml. Then repeat. This is probably the most annoying part about this pump and I would take off 1/2 star for it.

Those are the only real issues. I don't understand why Neptune doesn't allow for the pump to be completely controllable. But, it does a fantastic job of dosing 2 part and water changes, so overall I'm happy enough with it to buy two.

Was this review helpful? 5 0


Reviewed on
August 21, 2018

Yes, I would recommend this.

Reliable dosing

I switched from another brand dosing unit to the DOS units. I have been using them for over a year and no issues at all. They have been very reliable and accurate. It automatically breaks up my dosing through out the day and I can monitor them easily with fusion.

Was this review helpful? 2 0


Reviewed on
March 06, 2018

Yes, I would recommend this.

Accurate dosing

Works great. A little noisy but who care about little noise when it doses accurately and with excellent control

Was this review helpful? 0 1


Reviewed on
August 12, 2017

Yes, I would recommend this.

Using two of these dosers and pretty happy with them so far

so far this pump is doing a great job of dosing for me. In fact I have two of them, one for two-part and one for trace elements and vitamins. They are stacked and mounted on the wall in the cabinet. You can definitely hear when each pump activates; I wouldn't call it loud but I guess it would bother some people. They are super easy to program for frequent tiny dosages, through the Apex interface (meaning no crouching under the tank pressing tiny buttons), and they seem to be pumping accurate amounts. (It's also easy to recalibrate each pump if you have any doubt, and easy to flush lines of any air bubbles.) I was having a miserable time dosing two-part manually with pH swings and inability to maintain adequate alk levels; the doser fixed all that.

Was this review helpful? 2 0


Reviewed on
July 19, 2017

Yes, I would recommend this.

User friendly

Pros: User friendly

Cons: Needs neptune to use.

Product was super user friendly to set up, has saved me so much time with dosing chemicals. Product is a little noisy if in the open when active.Would recommend getting 1 link though if you have more than one DOS.

Was this review helpful? 0 1


Reviewed on
May 25, 2017

Yes, I would recommend this.


Pros: Great all around product

Cons: None

Works great for water changes

Was this review helpful? 1 0


Reviewed on
January 30, 2017

Yes, I would recommend this.

Great products from Neptune

Pros: Works great, easy to set up and run

Cons: None

If you are looking for this you likely already know about it, but fwiw I love it. Works great, easy to set up and run. Unlike some Neptune components the programming provided by Neptune is usable out of the box. I really like being able to adjust ml from the computer

Was this review helpful? 3 0


Reviewed on
April 01, 2016

Yes, I would recommend this.


Ease of setup and very dependable. I've been using this for a continuos water change and couldn't be more pleased, all parameters are consistent. Definately improvement over once a week water changes. Corals are much happier! Highly recommend this product.

Was this review helpful? 2 0

We use cookies to provide a personalized site experience. By continuing to use & browse this site, you agree to our Privacy Policy.