Proper Setup Using Dry Reef Rocks

Introduction

This guide focuses on setting up a marine aquarium using dry reef rocks or bio-ceramics without using traditional Live Rock biofilters. It's important to note that this is a complex and lengthy process requiring patience, understanding of biological cycles, and constant attention to detail.

Why Setup with "Live Rock" Is Often Not Recommended

Some aquarists choose dry rocks out of concern about introducing unwanted inhabitants—crabs, worms, and parasites—along with "Live Rock." However, this decision complicates rather than simplifies the setup of such a reef system.

A much simpler alternative is using "Live Rock," but placing it not in the main aquarium (display), but in the filtration compartment (sump). With this approach, all potential unwanted animals remain in the sump and essentially have no way to enter the main aquarium. In extremely rare cases, a worm might get through the return pump into the Display.

It's important to note that Aiptasia rarely arrive with live rocks. If you purchased rocks from someone else's aquarium and fear they may be infected with Aiptasia, they can be removed beforehand:

• Place the "Live Rock" in a separate container

• Set up a regular desk lamp above them

• Cover the rocks with Chaetomorpha (a type of algae) or a light-blocking net through which Aiptasia can crawl, drawn to the light

• After 3 days, all Aiptasia, if present, will crawl to the surface of the Chaetomorpha or net, and you can remove them along with the net or pieces of Chaetomorpha.

In the US, dry rocks became popular due to the ban on importing "Live Rock" into the country. This is a forced measure, not a preferred method of setup. Marketing justifications for the benefits of dry rocks are often just attempts to justify the necessity of using them.

Preparation of Dry Reef Rocks

If you still decide to use dry reef rocks, understand that they contain large amounts of organic matter that will decompose in the aquarium. Therefore, thorough preliminary preparation is required:

• Prepare a 3% hydrogen peroxide solution (mix peroxide with RO water in approximately a 50/50 ratio)

• Place the rocks in this solution, which should "bubble, hiss, and boil"

• Conduct the procedure in a well-ventilated area (on a balcony, in a garage, outdoors), as unpleasant odors are released

• Repeat the procedure twice, replacing the solution each time, until most of the organic matter is removed from the rocks

• After treatment with hydrogen peroxide, thoroughly rinse the rocks with RO water to remove hydrogen peroxide residues

• Load the treated rocks into the aquarium or sump

If you're using special artificial substrates (bio-ceramics), they're already clean, and such treatment isn't required.

Biological Cycle Startup

Starting a system on dry rocks is an extremely lengthy process that can take 5-6 months before the first signs of normal biofiltration appear. During this time, two main cycles must be maintained:

Nitrogen Cycle

• Requires an ammonia source to start the cycle

• Can use commercial bacterial starters (e.g., Turbo Start)

• Alternatively, use a natural ammonia source—ground shrimp in a meat grinder or a whole shrimp tail placed in the aquarium

• As such organics decompose and ammonia release stops, add a new source so the process continues uninterrupted

Denitrification Cycle

• Runs parallel to the nitrogen cycle

• Requires carbon dosing (serves as food for bacteria)

• Requires phosphate dosing for proper functioning of denitrifying bacteria. The Nitrate to Phosphate balance should be 1/0.14

• If phosphates are absent, bacteria won't be able to consume nitrates, which will continuously accumulate, exceeding the maximum recommended value of 20 units

Both cycles must function continuously for at least 5-6 months, until colonies of Anaerobic bacteria form in the depths (deeper than 1 inch) of dry reef rocks and detritus begins to form. The appearance of detritus (grayish-brown flakes) is a sign that your dry reef rocks are beginning to "come alive," as Detritus consists of dead bacteria that have colonized the rocks. True "Live Rock" has two biofiltration zones: an Aerobic zone up to 1.5 inches deep across the entire rock surface that forms in 2-3 months, and an Anaerobic zone deeper than 1.5 inches that forms in 6-12 months. If you've ever split a "Live Rock" to its full depth, you've likely noticed the black color of the Anaerobic zone and the unpleasant smell of Hydrogen Sulfide—this zone is especially important for biofiltration, and we have to wait so long for it to form.

Aerobic and Anaerobic Zones

In a properly functioning biofiltration system, there are two zones:

Aerobic Zone (with oxygen):

• Located on the surface and in the upper layers of rocks

• Bacteria in this zone convert ammonia to nitrites, then to nitrates

Anaerobic Zone (without oxygen):

• Forms at depths greater than 3 cm inside rocks

• Bacteria in this zone convert nitrates to nitrogen

• This zone is characterized by a faint hydrogen sulfide smell when the rock is split

Until the rocks are colonized by bacteria throughout their depth, biofiltration must be artificially maintained.

Accelerating Biological Filter Maturation

Several methods can help accelerate biofilter maturation:

Introducing Detritus

• Acquire and introduce detritus from an already functioning marine aquarium

• Detritus contains necessary bacterial strains and serves as a nutrient substrate

• As the amount of detritus decreases (consumed by bacteria), add more

• Continue adding detritus until the system begins producing it independently

Using Sand as a Temporary Biofilter

• Not recommended to use very fine sand as a regular decorative element

• For biofiltration, use fine coral grit (1-3 mm size)

• Place detritus under a layer of such coral grit

• Can create a separate container with sand and detritus and place it in the aquarium or sump

• Water flow should ensure water passes through this substrate

Coral grit is preferable to sand because detritus can fall through it and water can pass through, creating better conditions for biological filtration.

Monitoring and Maintaining Balance

During startup, several key parameters must be regularly monitored:

Nitrates

• Nitrate growth means the nitrogen cycle is functioning (ammonia conversion)

• Cessation of nitrate level growth indicates cessation of ammonia release from rocks if you're not dosing Ammonia or commercial bacterial starters (e.g., Turbo Start)

• Nitrate reduction (with phosphates present) indicates denitrifying bacteria are working

Phosphates

• Necessary for the denitrification cycle

• May "leach" from rocks or come from food

• If natural sources are absent, dosing is necessary

• Without phosphates, the denitrification cycle stops

ORP (Oxidation-Reduction Potential)

• Initially will be low due to high organic load

• Rising ORP indicates improved biological filtration

• Sharp ORP decrease after adding fish indicates increased system load

Detritus

• Appearance of light brown or gray flakes (brownish in white light, gray in blue light)

• Indicates active growth and death of bacterial colonies

• Gradual increase in detritus amount is a sign of system "coming alive"

Process Balance and Interruption Risk

It's important to understand that interrupting any biological cycle can cause serious problems:

Nitrogen Cycle Cessation:

• Occurs when ammonia stops entering the system

• Can be caused by stopping fish feeding

• Leads to disruption of the entire process chain

Denitrification Cycle Cessation:

• Occurs when phosphates or carbon are absent

• Leads to nitrate accumulation

• Disrupts the ecosystem's bio-balance

Interruption of these cycles often leads to a "flip" in biological balance and the appearance of Dinoflagellates or Cyanobacteria.

Introducing Inhabitants

Corals

• Can be introduced before fish, as they're less sensitive to ammonia

• Corals consume some Ammonia and Phosphates, which can disrupt balance in an immature system

• If corals reduce nutrient levels to zero, dosing is necessary

• Monitor water parameters after adding corals

Fish

• Start introducing Fish only after nitrates stabilize and begin decreasing

• Add fish gradually, monitoring ORP

• A 50-unit ORP decrease after adding a fish is a signal to wait for its recovery before adding the next fish

• The number of fish depends on the system's total volume and biological capacity

• Fish are important for maintaining the nitrogen cycle through waste excretion

Carbon and Bacteria Dosing

To maintain stable biological filtration, it's recommended:

Carbon Dosing:

• Use food-grade glycerin 90-95% (not vodka or sugar)

• Maximum dose: 1 ml per 200 L of water, start with ⅓ dose

• Half this dose is sufficient to maintain a basic bacterial level

• Excessive dosing can cause bacterial bloom and cloudy water

Bacterial Additives:

• Can use commercial products like "PRODIBIO"

• Quality and composition of bacterial additives may vary even within one product line

• Dose according to instructions

Signs of Bacterial Activity

For visual assessment of bacterial activity:

Pre-Bacterial Bloom:

• Slight haziness of water when viewed against light

• Is a minor problem and indicates excess bacteria in water and accelerated consumption of organics including Phosphate

Bacterial Bloom:

• Noticeable haze or cloudiness in water

• Indicates excessive carbon dosing

• Requires immediate adjustment of dosing regimen (stop carbon dosing for 3-4 days)

Signs of Successful Startup

The system is considered successfully launched when:

• Rocks begin independently producing detritus

• ORP steadily rises to 400-450

• Nitrate and phosphate levels are controlled by biological processes

• The system can handle increasing biological load

• Undesirable algae and cyanobacteria are absent

Major Mistakes and Their Consequences

Stopping Fish Feeding:

• Disrupts the nitrogen cycle

• Leads to bacteria starvation

• May cause Diatom algae, Cyanobacteria, or Dinoflagellates to appear

Uncontrolled Addition of Fish:

• Creates excessive load on an immature system

• Leads to sharp ORP drop

• May cause fish diseases (cryptocaryosis, odinium)

Absence of Carbon Dosing Including Organics:

• Disrupts the denitrification cycle

• Leads to nitrate accumulation

• Weakens bio-filter activity

Using Powerful Skimming to Clean Water During Bio-Filter Maturation:

• Increases ORP, creating an illusion of well-being

• Doesn't replace biological filtration

• May lead to long delay in biofilter maturation

Conclusion

Setting up a marine aquarium on dry reef rocks is a complex, lengthy process (about 6-12 months) requiring deep understanding of biological cycles and constant monitoring of water parameters. It's important to maintain continuity of all processes and prevent their interruption.

Main recommendations:

• Thoroughly prepare rocks before startup

• Create an additional biofilter (container with coral grit and detritus)

• Maintain Nitrogen and denitrification cycles

• Constantly monitor water parameters (Nitrate, Phosphate, and KH)

• Introduce changes gradually and observe system response

• Don't interrupt feeding and dosing

• KH is used in the Nitrogen Cycle process and can drop due to acceleration of this cycle and sharply recover (rise) due to a sharp decrease in the nitrogen cycle.

With the right approach and attention to detail, even dry reef rocks will eventually "come alive" and become an effective biological filter for your reef aquarium.