Step 4 Explained: What Bioactive Color Elements™ Actually Do

Introduction

It's easy to read the name Bioactive Color Elements™ and assume Step 4 is only about looks.

The manufacturer's Reef Essential® Aqua Care Guide™ says otherwise. These elements can boost the natural color of your corals, and they also help improve biochemical processes, health, vitality and growth rates.

There's a second surprise. Your reef removes these elements quickly, so they don't stay in the water for long once you've added them.

In this article, we break down what the Step 4 elements are, which colors each group supports, why your tank runs short of them, and how to dose them in your own reef.

What Are Bioactive Color Elements™?

Bioactive Color Elements™ is Step 4 of the five-step Reef Essential system. It comes after Step 3 – Aragonite Enhancers™ and before Step 5 – Bioavailable Nourishment™.

Step 3 looks after calcium, alkalinity and magnesium (CAM), the main components behind a coral's strong aragonite skeleton. Step 4 supplies the major, minor and trace elements the Guide links to coral coloration.

The step has three products. Each one covers a group of elements, and each group is linked to a range of colors:

• Bio-Gen™: iodide, bromide and fluoride, for white, blue and violet.
• Bio-Kalium™: potassium and boron, for red and pink.
• Bio-Metals™: iron, manganese and other bioactive metals, for green and yellow.

The Guide says each product supplies its elements in proportion to the typical uptake ratio.

How Step 4 Elements Affect Coral Color and Health

Each group does more than add color. Here's what the Guide and the manufacturer say about each one.

Iodide, Bromide and Fluoride for White, Blue and Violet

Iodide, bromide and fluoride can help intensify white, blue and violet coral color.

The Guide says they can also help reduce coral bleaching, improve calcification, provide antioxidants and act as a natural resistance improver.

Bio-Gen supplies all three. The Guide's targets are iodide at 0.06–0.09 ppm, bromide at 60–70 ppm and fluoride at 1.0–1.2 ppm.

For more on this group, read Optimal Iodine, Fluorine, and Bromine Levels.

Potassium and Boron for Red and Pink

Potassium and boron can help intensify red and pink coral color.

The Guide says potassium also helps transport nutrients, stabilize osmotic pressure and aid many biochemical processes. Used alongside boron, it can help corals produce strong aragonite instead of brittle calcite.

Bio-Kalium supplies both. The targets are potassium at 375–400 ppm and boron at 4–5 ppm.

Quantum's reef salts supply potassium too. The reef salts in the Guide's Step 1 all list potassium between 375 and 400 ppm, the same band as the Step 4 target.

We cover this pair in more depth in Coral Chemistry: How Potassium and Boron Create Stunning Red and Pink Colors.

Iron and Manganese for Green and Yellow

Iron, manganese and other bioactive metals can help intensify green and yellow coral color.

The Guide ties these metals to coral biochemistry through energy production and photosynthesis. Corals use photosynthetic zooxanthellae to make many of the nutrients they need.

Bio-Metals supplies iron in ionic, complexed and chelated forms, plus manganese and other trace elements. The manufacturer says the ionic and complexed forms are available to corals right away, while the chelated form gives a sustained release for a steadier supply.

The Guide's iron target is 0.005–0.015 ppm.

For the science behind this group, read Reef Aquarium Science: Iron and Manganese for Optimal Coral Pigmentation.

Why Coral Color Elements Run Low in a Reef Tank

The Guide gives a plain reason the Step 4 elements need topping up: reef aquariums remove them rapidly, through absorption and filtration.

That's why the Guide's Step 4 doses are daily doses, not a one-off.

The goal isn't a quick color boost.

The goal is to keep replacing what your reef removes.

Like every step except cycling, Step 4 stays in your routine for the life of your tank.

For a closer look at how these elements tie into coral feeding, read Trace Elements — The Invisible Nutrition Behind Coral Color.

When to Start Dosing Step 4 in Your Reef Tank

Step 4 comes after Step 3 for a reason.

The Guide moves on to Step 4 once you've set your CAM targets and put methods in place to control them.

If calcium, alkalinity and magnesium aren't steady, your corals won't take up Step 4 elements as easily. Your protein skimmer and chemical filtration may remove them first, and that's product wasted.

So get CAM steady with Step 3 – Aragonite Enhancers first. Then add Step 4.

Step 5 comes next. The Guide recommends feeding corals key biomolecules to help get the most from Step 4.

How to Dose Bioactive Color Elements™

All three Step 4 products share the same daily dose in the Guide, 0.5–1.0 mL/day per 100 L (26 gal), set by how heavily your tank is stocked:

• Lightly stocked: 0.5 mL/day per 100 L (26 gal)
• Moderately stocked: 0.75 mL/day per 100 L (26 gal)
• Heavily stocked: 1.0 mL/day per 100 L (26 gal)

The Guide also gives a second option: dose as required to keep each element within its target range. That means testing and adjusting from your results.

A few practical points from the manufacturer:

• Work out your dose from your true water volume: the tank plus any external filter, minus the space taken up by media, rock and ornaments.
• No shaking is needed. Add each product directly into an area of high water flow.
• All three can be used on a dosing pump.

Frequently Asked Questions

How Much Does 1 mL of a Step 4 Supplement Raise Each Element?

The manufacturer says 1 mL per 100 L (26 gal) raises total iodine by about 0.02 ppm with Bio-Gen, potassium by about 1 ppm with Bio-Kalium, and iron by about 0.01 ppm with Bio-Metals. The other elements in each bottle rise with it.

Can I Use Step 4 Supplements in an SPS, LPS or Mixed Reef Tank?

Yes. The manufacturer lists all three as suitable for LPS, mixed reef, SPS and non-photosynthetic (NPS) coral tanks.

Is There a Simpler Way to Dose Step 3 and Step 4?

Yes. The Guide's Easy Reefer® line combines the Step 3 and Step 4 products into two: Easy E™ and Easy Z™. The trade-off is less control over individual parameters.

Do Corals Need Feeding as Well as Step 4?

Yes. The Guide says zooxanthellae can't provide all the nutrients a coral needs, so corals need additional food sources for full-spectrum nourishment. That's the job of Step 5 – Bioavailable Nourishment.