Deep Substrate Vs Ei

>FatherFish...the name says it all...
The idea of plenums and deep sand beds and soil tanks works for some tanks, for some people , for some goals. For me I wonder why live with such limitations when plants and water changes are great, cheap, more predicatable and shown to support better looking tanks. If you want to get a better explanation at what happens in such anaerobic conditions think the video below will provide a way better explanation


In my opinon, in a high tech planted tank, a deep sand bed is fighting against your plants for nitrate. And many plants are fighting against the anaerobic conditions by pumping in oxygen near their roots.

Generally we consider that sand provides no nutrients, sometimes some calcium and magnesium is dissolved. The nutrition then comes from the other stuff we add to the substrate so you get some micronutrients from clay , iron etc and some macronutrients if you add soil. Plus some macronutrients from fish /fish food. In high tech tanks these sources either can't keep up with plant demand or are quickly depleeted. But there is another issue , what's in the substrate doesn't really always stay in the substrate. Even if you leave the plants alone, the nutrients from the substrate will slowly leach in the water column... ammonia from soil does this quite fast. Same with the added Mg. And in the end you have a fertilized water column anyway. Just from a source you really have no control over.

So it really depends on your goals with the tank. If you watch the plant selection, density and plant health in Father Fishe's tanks is pretty much what you expect. Similar plants as Walstad's tanks and it's no mistake that most tanks end up having these plants and look like that. A part of it is the method, a part of it is the hands-off mindset and goals. So if your goal is similar, follow their approach. Look at Tom's tank or IAPLC winning tanks , if your goal is that then frequent water change, (some) water column fertilization and very hands on approach are part of the game.

I think this would be the right place to upload a photo of a 2 year old Echinodorus grown in medium light in 5cm of pure sand ( no root tabs), just water column fertilization. The yellow bits were in contact with my lamp.

 

I agree with you there, nothing wrong with using rich substrates for your plant growth. You don't need much of it to get good plant growth, but it does have some downsides.It's a more traditional approach to plant growth so we know it works. A deep sand substrate, however, in my view is detrimental to plant growth as it uses up nitrates.

 

If you want a nutrient underlayer, yes you would need some version of soil . But the same anaerobic conditions can be had with sand. The hard part in my view is the unknown black box of what is in the soil at each point in time?, how much leaches in the water column?, when is it consumed?. A question that an average aquarium keeper cannot in truth answer with actual certainty.

With EI things don't go as you want with plant X, do a water change adjust parameters, adjust CO2 ... with soil you are unlikely to change the soil so eagerly. And you end up with a great unknown which can always be blamed for everything, both success and failure. With standardized 'aquasoils' you get a bit more predictable because the solid are quite standardized and controlled. Plus somewhat easier to change a part of the aquasoil of a tank.

That being said I don't see why you can't do a soil substrate and dose Ei, you would lose some nitrate but not the end of the world. Water column covers your basis, soil fill in the gaps. Just keep away from lilies and swords... i still recoil when I remember having those with a laterite bottom.