Review on Enhance Your Aquarium with Seachem Fluorite Onyx Sand Substrate: Unveiling the Incomparable Aquatic Bliss by Julie Burton

This stuff seems to work great. I have about an inch for every my 125 gallons under another inch or two of various substrates. All my plants are blooming. About 40% of my aquarium is filled with dense vegetation, the rest is lightly planted with various types of swords. I have not used CO2 in this tank before but have added Flourish and Flourish Excel from Seachem. My plants seem very happy with it, although I understand that Excel isn't as efficient as Co2 and that plants can't absorb it as well as real Co2. I would definitely recommend it to anyone thinking about planting an aquarium. Placing a layer of onyx sand in front of the main substrate should allow the onyx sand to be slightly obscured by the rim in most aquariums and allow your plants to deprive the onyx of vital nutrients. The size and shape of the onyx granules seem to prevent it from compacting and as a result the roots of my plants are always very healthy. However, keep in mind that many aquatic plants use their roots primarily to anchor themselves and actually leach most of their nutrients from their leaves. It's important to use a water-based fertilizer in addition to something like Onyx.