Will My Multiple Substrate-type, Deep "sand Bed", Plenum Be Effective? Or Just Way Overthought? Lol

Jacob C. Becker

New Member
Sep 15, 2019
Milwaukee, WI
So I have been in the process of building a 56 gallon "column" high tech planted tank for the better part of 6 months now. I have slowly been collecting each item (along with some limited DIY building) and am FINALLY almost ready to add water. May be a little late now lol but wanted some opinions on my substrate choices and its possibility for some nitrate reduction.
It started based off the well known article, put out several years ago, about freshwater deep sand beds. I later stumbled across some of Dr. Kevin Novak's videos on plenums, on Youtube, and thought to myself why not just do both? In my mind there is NO way that creating a plenum (with a tube coming out hooked up to a modified surface skimmer) to draw very limited amounts of water from the plenum void (beneath the sandbed) could possibly be bad. All it would do is create a small amount more diffusion of the water through the sandbed, and allow the sandbed to create more faculative heterotrophic (sp. butchering?) bacteria to reduce nitrates INSTEAD of possibly creating "severely anaerobic" conditions leading to the dreaded hydrogen sulfide production. ALSO (though now possibly thought of as a thing of past) came across a couple Hydor substrate heating coils VERY cheap and had the idea to add one or two (in case one fails) to heat up the lower substrate region, to create even more diffusion of H20, 02, and nutrients through the substrate.
Now, to the actual substrate materials. My idea was to create several layers. And it has evolved into quite a complicated little beast lol. I will share each item and its place in layers of substrate and just let me know if you all think its just stupid complicated and could never work? Orrr if each item and my idea for using it will create an overall good environment for plants, while possibly also reducing some nitrates with the bacteria grown within.
Bottom layer will be the empty void with nothing but the substrate heating coils. Above that an egg crate spanning the entire bottom of the tank covered with a fiberglass mesh to create the plenum. Also having a tube connected to my canister filter drawing just a couple gallons of water a day from below the plenum and the rest from the top of the tube (as described in Dr. Novak's video) Above the plenum a small layer of kitty litter with a bit of laterite sandwiched in the middle. Got this idea from Dr. Novak's anoxic filtration ideas and thought why could this not work as a bottom layer of a substrate? It could draw ions through the substrate, binding them to that bottom layer and also possibly also create more water and 02 flow through the bed. Above that would be a larger layer of Flourite black sand to keep some of the sand shape while adding some nutrients also. Above that a thinner "nutritive layer" of sorts consisting of Dennerle Deponitmix Pro 9 in 1 AND Sera Floredepot. I chose the combo of the 2 as Dennerle stopped making the Deponitmix JUST after I bought my first batch of it and needed more. The Floredepot was the closest I could find. They are both nutritious sand/peat mixtures with many other nutrients added for good plant growth. ALSO they are both MEANT to be buried under an inert substrate which would be my FINAL top layer...pool filter sand #20 mesh. I thought this to be a "deep sand bed on steroids" of sorts as the consistency of each type of substrate would end up VERY close to that of just plain pool filter sand, yet hold a purpose for plant growth. The substrate depth would total 4-6 inches total, through ALL parts of the tank (slightly taller in the back).
Pheww...what do you all think?? Realize it may take a bit of research on each of your parts to educate yourself before answering or I can attempt to answer any questions to the best of my ability as well. If you check anything out, Dr. Novacks plenum video on Youtube, Deidre Kyles (sp.) freshwater deep sand bed article on Google, and any of the substrate types Im using you are not familiar with, would help in your knowledge to answer (I'm new to the forum and cannot post links YET lol)...Will this "sand bed" function "properly"? THANK YOU to ANYONE who has read this whole post and taken the time to answer. It is greatly appreciated!!