Join Date: Aug 2014
Location: Fort Myers, Florida
Does Substrate Depth Affect Plant Growth?
So I've got two primary tanks both with inert sand, both heavily planted, and both low-tech. The smaller 20 high tank has a sloped scape with 3" of substrate in front and even more in the back. The plants in this tank are going gangbusters with the Corkscrew Val taking over, the Swords full and beautiful and starting to propagate, and even small shoots of Broadleaf HC I pulled off larger plants that I thought were too small are starting to take off. This tank just runs beautifully and like clockwork with zero problems of any kind. The larger 55 gallon tank has a wider variety of plants but none of them ever seem to do as well and I'm wondering if its because I only have 1.5" of substrate. The Crypt Wendtiis have always been stunted even when I used to have a dual T5 NO fixture on there. They put out a lot of runners but none of the mother plants ever become those full lush crypts you see in photos. Growth rates for the Giant Val are abysmal and they never put out runners. The Amazon Sword I purchased for this tank doesn't seem to like it much either. It has started to grow algae and doesn't seem to be growing at all. The HC does pretty well though so I'm not sure what to read into that. I use Osmocote root tabs liberally in both tanks.
Is it possible that a low substrate depth is holding this tank back? Most people seem to suggest 3" of substrate. What is the effect of a lower substrate depth?