While both are used as substrates for growing coral frags, they have different strengths in the aquarium. Frag plugs are designed to be used with a frag rack, frag tray, or individual mount by inserting the frag plug stem into a hole in the rack system. Frag rock discs, on the other hand, do not have a stem and therefore do not work well with frag racks. The flat base of frag rock discs is designed to sit naturally on the sandbed or be attached to a specific spot on larger rock structures with reef-safe adhesive.

Yes, the type of frag plug affects the growth of the coral frag. After water stability, nutrient levels, and lighting, the substrate plays one of the most important roles in overall coral growth. The porosity of the surface determines how naturally the coral frag may encrust and affects the development of the biofilm, and the mineral composition can affect the rate at which coral frags grow. Natural mineral compositions tend to create localized environments directly around attached frags that encourage faster growth.

Yes, but different materials are cured in different ways for different reasons. Ceramic frag plugs are chemically inert once cured, so they are ready for aquarium introduction as soon as the cure process is completed by firing the plugs in a kiln. Curing natural frag rock harvested from the ocean involves a continuous saltwater soak with water changes to remove excess ammonia and nitrite until reef safe. Curing cement based substrates involves a continuous soak in reverse oxidation deionization (RODI) water with water changes to remove excess alkalinity. Each of these processes is very different and performs different functions that make the specific material safe for marine ecosystems.

Corals generally require stable chemistry in the saltwater of their environment, including alkalinity, pH, calcium, magnesium, strontium, phosphate, nitrogen, nitrite, nitrate. Corals also require stable lighting with appropriate photoperiods similar to their natural environments, as well as some consistent but slightly varying water flow. Each specific kind of coral prefers unique parameters depending on how they grow, so it’s important to perform research on what your corals need to thrive.

Yes, all of our substrates were designed for all kinds of coral. The porosity produced by the varying grain sizes of natural minerals makes our substrates ideal for any coral frag, but some hobbyists find our substrates particularly helpful for propagating soft corals because the new frags naturally attach to them with ease. This means that a colony of zoanthid coral can be fragged and placed atop a bed of frag plugs or discs in an acclimation box to attach without the use of adhesive, ultimately leading to a more organic attachment and appearance. The main benefit for stony corals is a more organic encrustation pattern, which sometimes leads to faster encrustation.

That depends on the type of coral frag you are working with, your process, and your goals. Soft corals will attach to these substrates naturally if flow is mitigated and one to two weeks is allowed for attachment. Most coral frags, however, would still benefit from a small dab of reef-safe glue to create the initial attachment. Once the frag is secured to the substrate, the coral’s natural encrustation processes will begin, at which point the benefits of the superior substrate will start to play a role in the coral’s growth.

Yes, all discounts that are applicable to you are automatically applied at checkout. If you have questions or concerns about any of our discounts or specials please contact our team.

Yes, all orders over $20 after discounts include free shipping in the United States. For questions regarding shipping & delivery please contact our team.

Yes, we accept returns and exchanges within specific guidelines to ensure the biological integrity of our products.

• Returned items must be returned within 45 days of delivery.

• Customers are responsible for return shipping costs unless the item arrived damaged or incorrect.

• Returned items must be unused and in their original packaging. Once the return is received and inspected, approved refunds will be issued to the original payment method.

• Original shipping costs are non-refundable.

Damaged Items

If your order arrives damaged, please contact us within 7 days of delivery and include:

• A clear photo of the damaged product

• Your order details

Once reviewed and approved, we will:

• Arrange a replacement order, or

• Issue a refund or store credit when appropriate. Refunds may take up to 30 days after the reception of the returned item.

If a replacement shipment is required, we will provide instructions regarding shipping arrangements as soon as possible.