Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
No matter what substrate you use, you will be dosing fertilizer. As the plants use what is in the soil it is good to replace it as you go, rather than waiting until it is all used up.
Substrate with a high CEC is really good that way. Acts like a buffer so that fertilizer availability is more stable than with a gravel or sand substrate.
Dividing the cost of the substrate over the years of its use, and factoring something for your time and effort to add fertilizers I would give a big vote to any substrate that can become part of the whole system, and help with fertilizing the plants.
Start with a substrate with no fertilizer, but high CEC, and you will be adding a lot of fertilizer. Then it will get better with time, and be part of the system.
Start with a substrate with some fertilizer, and you may pay more up front, but have less fertilizer worries in the early stages of set up. You will still need to add fertilizer over time, though.
No substrate lasts forever in its amount of fertilizer or minerals that is offers to the plants.
Last edited by Diana; 05-03-2010 at 05:03 AM.