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Korallin BioDenitrator Nitrate Filter S-1502 w/ Eheim 1048 Pump


Starting at $40/mo with . Learn more

Item #: KL9111K

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  • Large internal volume with a small footprint
  • Optimal efficiency through high internal recirculation and fast Nitrate removal
  • Top-loading lid with detachable tubes for easy maintenance
  • No feeding liquid required!
  • Ultra-pure Sulfur (Sulphur) filling 99.9%
This revolutionary design makes denitrifaction easy and efficient. Feeding to the bacteria is not necessary; just put the unit into your system and let it run for a few weeks, denitrafication power will be activated once the unit is broken in.

The design is based around the C-1502 reactor and combine Sulfur (Sulphur) media with calcareous media to offer a high level of Nitrate removal. The recirculation method is far more efficient than simple single pass filters. As it includes reactor media, the pH is fully buffered and enriched with calcium before being returned to the tank.

With the build quality of the S-1501 reactor and recirculation, these offer very efficient nitrate removal. After a running in time of approximately 3-4 weeks (for the bacteria to colonize the chamber) this unit will, for example, reduce 100 liters with 50mg NO3 to 0 in 3-4 days.

Because this denitrator makes use of the design of Calcium Reactor C1502, once the nitrate problem has been solved, you can easily turn this denitrator into a Calcium Reactor with some additional parts (sold separately).

Comes with 1.6kg high grade pure Sulfur (Sulphur) and calciumcarbonat.

Korallin S-1502 - Rated for up to 250 gal. Reactor height: approx. 15.75"; Diameter: 4.50"; Footprint diameter: 6.30"; Included filter media: 6lbs; Eheim 1048 Pump.

Manufacturer information

Korallin is a German based company who is a manufacturer of specialized aquatic components and accessories for the advanced marine aquarist.

4 Stars


Reviewed on
July 20, 2020

Yes, I would recommend this.

needs better setup guide

Pros: well built and works

Cons: documentation only gets 1 star. or as a letter grade a d or d-

years ago in had one but with the time passed i found the one page of instructions not very clear, looking at the photos of the pump and at the whole kit i am not recalling how the flow works. it would be a great help if they added one page with a good diagram of the flow thru the reactor and an explanation of how the pump will circulate the water thru the media.

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Reviewed on
January 17, 2020

Yes, I would recommend this.

Money was tight - support was great!

I purchased this during December sale, money was tight and I had to return this. But I did had a few questions for support during transit.

I emailed Korralin support in regards of the product on Christmas eve and received a response in an hour! also answered my question on New Years day!

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Reviewed on
June 03, 2019

No, I would not recommend this.

Doesn't do anything, Marine Depot does not help

Pros: None

Cons: Doesn't do anything.

This does not do anything. I set it up about 2 months ago. It only works at a very slow pass through rate, if I raise it it does nothing. Marine Depot has not answered my questions about this $500 unit which makes me want to not shop here any more.

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Reviewed on
March 26, 2019

Yes, I would recommend this.


When it works, it is absolutely stunning. I have a 175 gallon reef where I was struggling with my nitrates being at around 40. This thing cranked up with a tank full of fish and coral brings my nitrates down between zero and five. The only issue I have with it, is that it clogs easily. The end let an outlet tubes as well as the circulation pump clog with gunk very easily. Because of this, the pump ceases to pump water through the bottom of the Denitrator, rendering it useless. Unless you catch this when everything starts clogging up, you will be pumping water with the same amount of nitrates that the Denitrator is pulling back into the tank. I would say this. If you keep the thing clean and know when to check it for maintenance you should have no problems.

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Reviewed on
September 23, 2017

Yes, I would recommend this.


Pros: Works as described!

Cons: Setup Instructions should be more clear!

After 1 week Denitrator is putting out Zero Nitrates! Tank is currently 30ppm. Let's see what happens in 2 months! So far so good and works as promised!

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Reviewed on
May 14, 2017

Yes, I would recommend this.

Awesome - works great!

Pros: Excellent quality product

Cons: None

I purchased this S-3002 Korallin biodenitrator for my 2-tank (210 gallon/85 gallon hex) /1-sump reef/saltwater setup. I was told my others that a denitrator is not needed on such a large setup, but I don't want to take any chances with how expensive reef livestock can get. It works like a charm! Just make sure to carefully follow the instructions that accompany the unit for both setting it up and breaking it in (establishing the anaerobic bacteria colony in the reactor).

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david anglin

Reviewed on
July 15, 2016

Yes, I would recommend this.


The instruction neglect to describe the overall set-up and the schematic of the plumbing is poor. Here is my take: The pump is used to make a high flow loop into and out of the reactor from which (and to which) a slow drip of water from your tank/sump flows. This keeps the reactor anaerobic with sufficient turbulence to keep the bacteria happy. So the large diameter short tubing sections connect to the pump to make a loop into and out of the reactor and the small lines go to the tank (sump). I used wire ties to prop the pump up in position. I hope this helps with set-up.

Was this review helpful? 8 0

alexander stross

Reviewed on
June 26, 2016

Yes, I would recommend this.


So my nitrates have been doubling every day in my 365 gallon discus/south american tank so I had to do 200 gallon water changes everyday. I installed this denigrator last Thursday and the effluent is already coming out with 0 nitrates and my nitrates have stabilized around 10ppm and seam to be going slightly down already! Though the manual is not perfect it's easy to assemble and get running. I'm very please and my fish seem to be too.

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Reviewed on
October 28, 2015

Yes, I would recommend this.

Best tank purchase EVER!!!

First, the bad: as others have mentioned, the manual is mostly worthless. Neither of the pictured hoses was included, meaning one of the valves was missing as well. Between youtube and a quick trip to the hardware store, however, those two negatives were eliminated quickly. Those two issues were annoying enough that I normally would not give a 5 star rating, so the fact that I AM giving a 5 star rating speaks to how much I love this product and how well it works. Cycling can take a few weeks so patience is required, but once it is cycled you will be dancing a happy dance because your nitrate export problem has just been solved without the need for a deep sand bed or biopellets or any of that other stuff. My tank is so simple and yet so beautiful. I don't even need a sump with this thing. A modified canister filter (all mechanical filtration removed), a protein skimmer, a bunch of live rock and this denitrator are absolutely the only filtration I'm using and my fish and corals are doing great! Oh and did I mention that my nitrates are ZERO despite not having done a water change in 6 months? Well not zero anymore, my tank got TOO clean and so I run this a little less efficiently than I could to keep the corals happy. Since my water changes have become all but non-existent, I do dose trace elements weekly. With this up & running, I NEVER have to dose calcium but my alk depletion rate is a little higher than before. Dosing addresses this just fine, but I'm really after as little maintenance as possible. Therefore I am most likely going to be adding a calcium reactor in the near future. Once that is done, apart from daily feeding and weekly dosing of trace elements, I will have a maintenance-free tank. I have not done a water change in the 6 months since this unit cycled and everything is doing great.

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fred mentzel

Reviewed on
October 02, 2015

Yes, I would recommend this.

Expensive but really works

Included instructions are accurate but minimal, difficult to follow and no pictures. However youtube is easy to follow. I had been struggling with Nitrates for years with my 55g. Up and down, up and down. Installed the Denitrator on 1/6/15 with tank at 40 ppm Nitrates. After it cycled (which took about one week) steady slow Nitrate decline. On 2/10/15 Nitrates are at 5 ppm and continue to decline. Marked improvement in corals. And as the product advertises, the media helps buffer the pH although I still need to dose more Alk than I was before installing the denitrator. Overall I am extremely satisfied - solved the most stubborn problem for me with nitrate control. 5 stars for sure. Expensive but absolutely works perfectly and with almost zero maintenance.

Was this review helpful? 4 0

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