MarcoRocks Coralline Colorant

MarcoRocks Coralline Colorantis the easy way to give freshly cycled dry rock the rich purple-pink hues of a mature reef — without waiting six months for natural coralline to fill in. Spray directly onto dry rock, aquascape components, or sumps to instantly add the classic reef look. Compatible with reef tanks of any size and a perfect pairing for new aquascapes built with MarcoRocks dry rock or any other cured reef rock. Browse all aquarium additives or our full saltwater supplies for everything else your new reef needs.

Why Use Coralline Colorant

• Instant aesthetic upgrade— new dry rock can look stark white or beige; a quick mist applies natural-looking coralline tones in seconds.
• Reef safe— colorant is formulated for marine aquariums and is safe around fish, corals, and inverts once dry rock is placed in the tank.
• Goes a long way— fine-mist spray bottle covers a lot of surface area; a 2 oz bottle handles most small-to-medium aquascapes.
• Pairs with bacterial cycling— apply colorant before or during your initial cycle; once the tank is running, real coralline algae will gradually take over on top of the colored finish.

How to Use

1. Start with dry rock— works best on bare dry rock, MarcoRocks, or other reef-safe aquascape rock before placement.
2. Spray a light, even coatfrom 6–12 inches away. Build up color gradually — multiple light passes look more natural than a single heavy coat.
3. Let dry fullybefore placing rock in the tank (10–15 minutes is usually enough).
4. Place rock and add saltwateras normal. The colorant adheres to the rock surface and will not cloud the water.
5. Top up over timeif desired — natural coralline will eventually grow over the colored surface, deepening the look.

Specifications

Recommended Pairings

• Brightwell MicroBacter Dry Rock Bacteria Starter Kit — cycle freshly aquascaped dry rock fast
• Red Sea Foundation A Calcium — supports natural coralline growth long-term
• Red Sea Foundation B Alkalinity — the other half of the Ca/Alk balance for coralline
• All aquarium additives & supplements
• Salt mixes — start your reef with quality saltwater

FAQ

Is this real coralline algae or a colorant?
It’s a cosmetic colorant designed to mimic the look of mature coralline. It gives instant color without the 3–6 month wait that natural coralline takes to develop. Real coralline will eventually grow over top once your tank is established.

Will it cloud my tank water?
No — the colorant adheres to the rock surface after drying. Let your rock dry fully before placing in the tank to minimize any rinse-off.

Is it safe with fish and corals?
Yes, the product is reef safe once dry. We still recommend applying it before livestock is in the tank (most people use it during initial aquascape setup or when adding new rock).

How much rock will one bottle cover?
A 2 oz bottle treats roughly 20–40 lb of rock depending on coverage density. Light, even coats stretch much further than heavy passes.