The substrate in a planted tank is important, but it does depend on lighting levels and the plants kept. I'll start with the low-light planted tank, since its very straight-forward.
Low light substrates
Pea Gravel/expoxy gravel
- this is your cheap, run-of-the-mill substrate, and for a low light tank, it'll be fine. You're not going be keeping a wide variety of plants due to your lighting, so they really won't need a fancy substrate. If you happen to keep crypts, you can simply use fertilizer tabs under those plants to provide the nutrients they need.
- pool filter sand or sand blasting sand works great. Play sand isn't the best because its such a fine grain, but it's doable.
Tahitian Moon Sand
- almost jet black, light, but coarse, and makes a pretty good substrate, even if you have more light than 'low light'. Again, you can use root tabs to target feed plants that need it.
Additives for low/medium light substrates
- basically small fertilizer tabs you insert in the substrate under or next to plants. They will feed a 6" diameter. SeaChem makes some good ones, or you can buy powdered clay and Plantex CSM and roll your own. Some people also use Jobe's plant sticks for Lush Ferns and Palms. This is the ONLY Jobe's plant stick that should be used in an aquarium, and you'll need to cut them into 3rds. They should never be exposed to the open water for long, as they are very nutrient rich and will cause algae blooms if exposed for long. I don't really suggest you use them, but if you have no alternatives...
- this is a clay based, iron rich substrate additive. You basically put a layer down in an empty tank, then put your sand/gravel over it. Laterite will cloud the water if it's disturbed, and it doesn't last forever. I haven't used it, but I believe it has to be replenished every one to two years.
Medium/High light substrates
- SeaChem makes this, and it's the oldest plant substrate and widely available. It's a very hard clay, basically light rock but kind of light. It very slowly breaks down to release the iron it contains, and also has good nutrient storage ability. That means the mulm that settles into the substrate will break down into usable nutrients that the plant roots will soak up. Its less common to need root tabs when using Flourite, but heavy root feeders like sword plants and crypts will benefit from their use. While flourite does break down, its such a slow process that you should never have to replace/replenish it.
Flourite comes in regular (rust colored bits with black specks) and 'red' (rust colored only, and reportedly more dusty than regular). Both types need to be rinsed thoroughly, and will still cloud the tank a bit when disturbed.
- Carib Sea started making this a few years ago. Its dark charcoal black in color, doesn't require rinsing, and has a great ability to hold nutrients. Eco doesn't break down, so it too will last forever.
- This is considered an advanced substrate setup. Typically consists of layers of peat, soil, sand/gravel...you really have to know what you're doing before you attempt this. For more details, I suggest Diana Walstad's "Ecology of the Planted Aquarium", which goes into great scientific detail on planted tanks and layered substrates. Again, this isn't for the new planted tank keeper.
After 2 years of constant use, I have decided that Flourite is inferior for plant growth as compared to Eco-complete. It is too heavy for some 'runner' plants to properly latch into and thus their growth is affected. With that, and clouding issues every time you move a plant, it's just not as convenient as Eco, and frankly I've had plants do far better in Eco under less light and CO2
than in Flourite.
(This thread is for information and resources only. Post questions in new threads. -- czcz, 9/06)