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Neptune Trident - Marine Aquarium Water Analyzer


Starting at $55/mo with . Prequalify now

Item #: NS1960

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A key ingredient to a great reef aquarium is maintaining proper levels of Alkalinity, Calcium, and Magnesium.

The Trident is an automated testing system that regularly tests alkalinity, calcium, and magnesium in your saltwater aquarium — and then communicates this information to your Apex so you can get alerts, and change your dosing. When combined with the DOS (available separately) it creates a fully automated system for the proper dosing of supplements, maintaining them at consistent levels. So, you can finally toss all those test kits; they are a thing of the past.

With the Trident, you will stay updated on your Alkalinity, Calcium and Magnesium values anywhere in the world, with zero effort.


  • Automated Alkalinity, Calcium and Magnesium Testing

Using an automated titration method, with colormetric identification, the Trident automatically tests your aquarium water up to 24 times a day for Alkalinity, Calcium, and Magnesium.

  • Incredible Precision

The Trident tests consistently with a precision of +/- 0.05 dKh for Alkalinity and 15ppm for Calcium and Magnesium. Using any hobby-grade test kit on the market, even humans cannot perform the tests that consistently.

  • Easy Plug and Play in 15 Minutes!

From the box to testing in under 10 minutes! Unlike other testing systems, there are no reagents to mix, tubes to cut, or pumps or probes to calibrate. Simply plug in one cable, two tubes, and run the setup task on the Apex Fusion mobile app — it holds your hand through the installation with helpful videos along the way.

  • Easy to Read Results and Graphs

The peace of mind of having your recent tank parameters, right there in your pocket, from anywhere in the world.

  • High/Low Alerts when Tank is Out of Range

Your Apex will alert you on your mobile device when test results fall out of the range you specify.

  • Controls Dosing to Maintain most Consistent Levels Possible

When the Trident is combined with the DOS system (sold separately), the two work in concert. Your Apex will use the data generated from Trident tests to automatically and safely adjust up or down your dosing amounts to keep your tank levels as stable as possible.

  • One Month`s Supply of Reagent Stores Neatly Inside

Convenient and clean, the Trident is self contained and when running the basic testing regimen only requires a reagent change once a month.

  • Uses Less than 7ml Tank Water Per Test

Some testing systems use as much as 100ml of your tank water for every test. This can cause fluctuations in tank salinity. With the minimal sample taken by the Trident, there will be almost no effect on your salinity. Unlike other solutions, potentially contaminated test water is never sent back into the aquarium. Instead, it is sent it to a waste container or drain.

  • Incredibly Quiet

The Trident is so quiet that our customers have said they rarely hear it – and when they do hear the quiet little chirps they are pleased to know that new test numbers are coming soon and they never had to pull out a test kit!

How does it work?

The Trident is a self contained automatic titration colorimeter. That’s quite a mouthful, for sure, so let’s state it as simply as we can. The Trident is basically automating what you (and top scientists) do already when you test your water, that is, perform a color changing titration and interpret the results.

On a scheduled basis the Trident carefully mixes its reagents with a small amount of sample water from your aquarium. While doing this, it is measuring (titrating with a precision peristaltic pump) the amounts of each that are necessary to reach an expected color change (determined by the electronic colorimeter). When it finishes the titration, it sends this sample/reagent fluid to your waste container. It then interprets the results of that test and logs the value into your Apex.

Plug and Play

From the box to testing in under 15 minutes! Unlike other testing systems, there are no reagents to mix, tubes to cut, or pumps or probes to calibrate. Simply plug in one cable, two tubes, and run the setup task on the Apex Fusion mobile app — it holds your hand through the installation with helpful videos along the way.

Understand your Aquarium like Never Before

When you start getting the regular data coming in from the Trident you will be amazed at the things you can see happening. The daily light cycle swing on calcium carbonate uptake. A salinity drop by watching magnesium. An out of sync dosing of calcium. This increased understanding ultimately helps you maintain a better, more successful reef.

Out of Range Actions and Alerts

You can set up your Apex to alert you, or take immediate action(s) when a parameter falls outside of the safe zone you specify. As just one example, you might be dosing an Alkalinity solution and a misconfiguration could lead to overdosing of your tank. The Trident will catch that, alert you, and give you more time to make that correction before its too late and to save your aquarium. The data from the Trident can also be used to turn on and off other devices (like dosers or solenoids) to protect your tank even more.

Automatic Dosing Control - Ultimate Stability

The more stable you maintain proper levels of Alkalinity, Calcium, and Magnesium, the better your corals will grow and thrive. But coral uptake of these supplements often changes and requires us not only to perform more testing, but also seems to put us in a never-ending state of adjusting our dosing levels.

The Trident, when paired up with one or more of our DOS systems solves this problem with Automatic Dosing Control (ADC)

When configured on the Apex, ADC will take the results it receives from the Trident and use them to gradually turn up or down the amount of additive your DOS delivers. But, don’t worry, we have built this feature with safety in mind. With ADC you set your target value and your starting dosing amount and ADC will only tune that dosing level +/-35%. If it takes more than that amount of dosing to keep your aquarium at your target value, then the Apex will stop ADC, revert to your starting dosing amount, and alert you that you need to manually adjust your dosing level. Then, ADC can be reenabled and it will continue to guide your DOS so that it keeps you as close to your target value as possible.

It is possible to use ADC for all three tests – Alkalinity, Calcium, and Magnesium. You can also use one test value to adjust up or down more than one additive delivered by the DOS (i.e. Triton system).

Simple, Infrequent Reagent Changes

When using the default testing schedule of four (4) alkalinity, two (2) calcium, and two (2) magnesium tests a day, the reagent stored inside the Apex will last a full month. And adding new reagent is super simple — just slide out the drawer, remove the old bottle(s), and replace them with new ones. If you desire, you can also run a calibration with the included calibration standard.

Reasonably Priced Reagents, about 9 Cents per Test!

The cost of reagents and recurring cost is a valid concern for a hobbyist considering the test kit or automated system – and we designed the Trident with that in mind – keeping those costs as low as possible. Reagent comes in 2-month kits (based on the default testing schedule of 4-Alk/2-Ca/2-Mg per day). These kits include two bottles of Reagent A (changed every month), one each of Reagent B and C (changed every two months), and one bottle of our calibration seawater sample. The reagent kit has at least 240 alkalinity tests and 120 tests each of Calcium and Magnesium. These two-month kits are priced at just $44.95 in the U.S.

Super Quiet

You will hear the Trident operate from time to time if you listen closely or you have a super-quiet room. And, as compared to other automated testing systems, it is several dB quieter. While inside your cabinet along with your other equipment, you will likely never even hear it.

Highlighted Features:

Automatically tests seawater for Alkalinity, Calcium, and Magnesium

Up to 24 Alkalinity tests per day with +/-.05 dKh precision 

Up to 12 Calcium tests per day with +/-15 ppm precision 

Up to 12 Magnesium tests per day with +/-15 ppm precision 

~7.9ml sample water used per parameter tested 

~7 minutes testing time per parameter tested 

Up to one month of testing before reagents need changing based on base level testing of 4-Alk, 2-Ca, 2-Mg per day. 

When combined with DOS system (available seperately), the data from Trident can be used to automatically raise or lower the amount of additives dosed as necessary to maintain stability at user set point.


Apex or ApexEL (not Apex Classic, Lite, or Jr.)

Available 1Link port OR 24v power supply and Aquabus Cable (available separately) 

External waste container or drain 

Must be located within 4’ of water source to be tested



1Link cable (US/CAN only) 

5` of black sample line tubing 

5` of clear waste line tubing 

1-month reagent supply 

Calibration Fluid 

Get Started Card

Physical Dimensions:

10"H x 4.25"W x 12"D

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
April 05, 2021

Yes, I would recommend this.

Trident met expectations

Pros: Ease of use and setup. Trident dosing!

Cons: Price

I have to say so far I am loving the Trident. It has been spot on and now I have one less thing to worry about with my water parameters since it tests throughout the day and I can check it on Fusion or even get an alert if something is off. A little piece of mind makes this worth it for me. Marine Depot also made the purchase easy with their payment plans and great customer service. Thanks!!

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Reviewed on
January 24, 2021

Yes, I would recommend this.

Why did I wait so long!!!

Pros: Worry free water parameters without the hassle of manually testing

Cons: none to date

I don't know why I waited to long to purchase this item. I have 3 systems and testing is cumbersome. So much so that the last time I tested was in September 2020 it is now January 202. Up to that point I was testing weekly for years. I purchased and installed the Trident 3 days ago. OMG why did I wait this long the Trident is a game changer. So far so good it works flawlessly. No more setting aside time on Fridays to do water testing. I have the Apex, DOS, DDR, Trident. By far the Trident is my favorite piece of equipment.

Was this review helpful? 1 0


Reviewed on
January 21, 2021

Yes, I would recommend this.

Neptune Trideant

Pros: automatic water testing at the same time everyday. Can control Netune DOS for trident controlled dosing based upon set up of DOS for more control of stability. Displays results on fusion dashboard so you can monitor any time. Replacing the reagents is very easy. Cost of reagents is compareable to red sea or anything like that. It is really quiet. Mine is out side of stand and I can barely hear it.

Cons: Have to replace reagents every 2 months.

This thing is a beast. It does exactly what it is suppose to do.

Was this review helpful? 1 0


Reviewed on
September 28, 2020

Yes, I would recommend this.

Big boy

Pros: less worries

Cons: None so far

This beast is a game changer! Perimeters are more stable than ever and now I can does the right amount and not worry too much on my level is dropping. Most importantly it gives me ease of mind

Was this review helpful? 0 1


Reviewed on
September 08, 2020

No, I would not recommend this.

Starts out good and Goes to Bad

Pros: When it works Great

Cons: When it doesn't work, a nightmare

I have been using my Trident for about 6 months and it started out well but now I am getting a bad CA range reading, Neptune support is very cumbersome and time consuming, which makes me kind of regret using their items overall.

Was this review helpful? 0 3


Reviewed on
August 30, 2020

No, I would not recommend this.

Open letter to Apex Neptune: Lack of 6 month reagents

Pros: Excellent, monitors my tank with precision

Cons: Lack of 6 month reagents

Dear Neptune Sales, Operations and Planning Teams,

First off, thank you for putting out a fantastic product. But I, and many others, have an issue:

This is beyond ridiculous. Please just tell us when the 6 month supply of reagents will be back in stock. I understand and appreciate the COVID-19 impact, but I also work in Supply Chain and can absolutely assure you that China and other SEA countries are back up to full production. Even accounting for the fact that you're likely shipping via Ocean ( with a 1-2 month shipping time). Please stop using COVID as an excuse. You were unable to keep your supply up with demand prior to COVID and show no signs that you're getting any better.

Feel free in passing this message along, or deleting, but your Supply Planning is an absolute wreck and is frankly very likely misaligned with an actual S&OP process. Or, Neptune is not capable of ramping up production capacity within their supply partners or in finding additional capacity with other partners. Your customers are losing faith and bombarding the Neptune with one-star reviews because of the lack of 6 month reagents.

When can we expect the 6 month pack supply to be in stock?

Please do not respond with the point that the 2 month supply is in stock. That's very well known and is at a much higher cost point. Unless you'd like to sell us three of the 2 month packs for the price of the 6 month supply.

Seriously, it's been over a year. Get your act together. At this point, it's just getting embarrassing.


Previously loyal, but getting frustrated customer base

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Reviewed on
September 09, 2019

Yes, I would recommend this.

The Bomb

Pros: Works like it suppose to .accurate

Cons: None

The trident is the best product on the market yet Neptune systems out did there selves with this one . I especially like how it controls my dos pumps to put the the right amount of calcium and alkalinity in my tank , it’s a real game changer

Was this review helpful? 0 1


Reviewed on
August 30, 2019

No, I would not recommend this.

Save Your Money

Pros: Fantastic concept, it would be a game changer if it worked properly

Cons: Readings are all over the place and each test is kind of expensive.

I was really hopeful that this would work but after a month with it the readings are all over the place and making zero sense as to why, I have relegated this to manual testing and use my Hanna and other test kits to confirm the readings. I have been reading on forums that others are having the same issues. My guess is that this was sold without adequate testing.

Was this review helpful? 0 0


Reviewed on
August 30, 2019

Yes, I would recommend this.

The Trident Rocks!

Pros: Everything

Cons: Reagents bottles eaked a little during shipping but not enough to be a problem and I believe neptune is addressing this issue.

Absolutely love it, had it connected to the Apex and up and running in less than half an hour. The trident is definitely a game changer in our hobby that will help many reefers succeed where they were failing before! Shout out to Johanna with Marine Depot customer support for the awesome service and help, she went above and beyond and I really appreciate it!...... Happy Reefing'

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Reviewed on
August 09, 2019

Yes, I would recommend this.

Just awesome

Pros: Everything

Cons: Nothing

This is a game changer. For my tank Alk consumption goes up and down a lot. Now, the Trident tests multiple times a day and adjusts my dosing. Tank has never been more stable.

Was this review helpful? 0 2

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