Quote:
Originally Posted by dwalstad  Easy Explanation. If you have a light scattering of gravel (1/4" deep), oxygenated water will flow over it keeping it aerobic. Nitrifying and other anaerobic bacteria will colonize the gravel. All good!
If you have a gravel substrate that is 2-3" deep, then oxygenated water doesn't penetrate that very well. Also, somewhere in that 3" are deep pockets that accumulate organic matter that make it really anaerobic and toxic.
When I see gravel substrates of more than 1", I just cringe. If you want that deep a substrate, then make sure that you vacuum it frequently. |
Does this applies to inert substrates ( like flourite, playsand, regular aquarium gravel ) or its only a concern with the organics substrates used in "el natural" setups due to significant ammounts of organic matter trapped under the top layer ?