Setting up a planted tank is one of the most beautiful and rewarding experiences in freshwater fish keeping. Not only will your aquarium look natural and provide cover for your fish (which keeps them happy), the plants will help keep the water free from nitrates and other toxic biological compounds. Most of my tanks are at least semi-planted and I almost never have “random fish deaths” in those tanks. Plants in my opinion can act as a buffer to keep the water more stable for your fish.
When you set up a planted tank there are many things to consider, such as which plants to pick, which lights and how much, and of course the substrate. For today lets focus on the substrate since it’s the foundation of your tank. If you are like most people, you go to the pet store and buy their overpriced bags of colored gravel. You end with an empty wallet and up wondering why your plants won’t grow properly.
The only thing from the typical pet store you are going to need for this is box of laterite. Laterite is a clay like substance that contains iron, which plant roots need to grow properly. A typical box for a 40+ gallon aquarium will probably run you about twenty dollars. Next go to a hardware store like Orchard Supply or Home Depot and take a look at their sands and gravels. Typically you can find a 50lb bag for around five dollars. Personally I prefer to have a nice texture to my gravel so it looks natural. I usually buy a second bag of a larger size that I will mix in.
Make sure to completely rinse the laterite and other substrates in buckets before putting them into the tank. The laterite is tough to get clean so do the best you can. When you are ready, lay the laterite down first evenly or more concentrated where you think you might have more plants. Next, if you chose 2 or more other components, mix them together until you create a texture that looks good to you. Place the mixed substrate over the laterite, completely covering it.
For most tanks, I’d say 2-3 inches is fine for substrate depth. When filling the tank with water, pour slowly and carefully or you will stir up dust and powder from the laterite. Also be careful if you only used sand with your laterite. Sand is fine but sometimes it (and this is rare) can compact and create toxic bubbles of bacteria. When it’s mixed with something else it’s more unlikely this is going to happen. A good burrowing fish can also prevent this too, much like earthworms churn soil. Your gravel should have a nice rich, natural look and be ready for plants….good luck.