Boil the dirt to avoid ammonia and make all the organics into available minerals. Cheap clay is just clay, has no "ingredients" and will be fine. The high CEC the clay provides is crucial but almost any soil has enough clay without added clay. Stay under 2" of dirt to be gas safe. Cap depth depends completely upon grain size and can range from .75" for the finest grain up to who knows what. Your Plants will be guaranteed to THRIVE and will even be able to denitrify nitrate back to ammonia at the anaerobic root rhizoplane (yes it does go anaerobic despite what many say). It is a more complete version of real life aqautic plant systems. Plantbrain himself reccomends that it is a good compliment to his EI, which is incredible if you stop to consider that EI alone should provide MORE that everything needed, so..... It will fail for those, like me who cannot stop uprooting stuff and or keep too many big heavy waste producing fish which overloaded the non vacuumable sand.
Thanks for all the advice! Sorry, but this brought up more questions
. If I rinse the soil a few times with boiling water, will that be excessive? I am leaning more towards sand as a cap to be safe on the barbels of the loaches I plan on getting, so 0.75" will probably be where I start and I can add if needed. I like the guarantee the that plants will thrive
. I have seen the root systems that my stem plants form and really think that dirt would help a lot being an easier way to get nutrients.
So, if I am understanding this correctly, the plants denitrifying the nitrates at the roots seems like it would be similar to deep sand bed bacteria. It seems like outside of the better plant growth, the aquarium is more complete (like you said), but would also be more stable. I don't plan on keeping any heavy waste producers mostly for the fact that I don't want to overload the aquarium with waste. Plus, most heavy waste producers (other than the BN pleco) won't work in a 29 gallon. I do have a plan in my head for all the plants so I don't uproot things more than needed.
Thanks again, I really like learning all the aspects of aquariums that I can, and the plants denitrifying nitrates in this way sounds fascinating to me. This brought out the nerdy ecology student in me
Ive had some bubbles, but if you plan on the tank being heavily planted, that will solve most of any problems you might have. Keeping the dirt under 2" will also help that cause. You could also get some malaysion trumpet snails to keep the dirt aerated. Its usually not a problem
Ok, that is good to know. I do plan on going heavily planted and I have some unknown amount of trumpet snails for the sand in my 20 gallon. I forgot to ask earlier, but how much dried clay can be added?