Aquasoil seems to be the go to substrate for aquatic gardening now adays. Its ability to hold its form without having to be capped and how it holds a slope, aside from its plant growing capabilities, leaves nothing to be desired, except maybe a lower price tag. Given the extensive lengths i have seen on this forum in terms of DIY projects, I was very surprised at the lack of precedent when trying to find a method for creating your own aquasoil.
I did find a thread on another forum where the OP found some similarities between the properties of humic acid and those of Aquasoil, namely the colloidal properties, buffering capacity, and leeching when placed in a highly alkaline environment. The granules that were pictured also looked very similar to aquasoil. I did a little reading on humates and learned they are key elements in growing plants. They help enrich the soil by promoting water retention, make trace elements, namely iron, bio available for uptake, and with all sorts of other beneficial properties pertain to plant growth and health.
Browsing along I found a website with some rough translation of descriptions about the materials and process used to produce Oliver Knott's Naturesoil. Seemed simple enough though, mine some top soil and some high CEC clay, mix them up and bake at 400 degrees, then again at 200 degrees.
I have also heard that some brands of aquatic plant substrate use some carbon or coal, which is a material the humic acids are derived from, well lignite to be specific.
Has anyone tried to make/bake there own topsoil/clay/carbon(coal)?/sand? mixture fortified with a humic acid solution?
Now I'm sure its not as simple as dumping some ingredients in a bucket and tossing it in the oven, but how hard can it be? I need to get a little more cash before I can start experimenting with this but it shouldnt cost to much. Topsoil and clay can be dug up if need be, I personally want to try using worm castings but either or, sand and carbon is cheap if you want to use it. The humic acid may be a little more tricky to get, but there is a site that sells it in powdered form at 80-90% pure humic acids($15/lb) allowing you to make any concentration. You can also get various forms of this at hydroponic/organic gardening shops. There is information out there on the interweb from studies done to show what levels of humic acid are beneficial and at what point the levels are to high to provide a baseline for creating the substrate. Just remember that peat and soil already contain a little bit of humic acid naturally
Everbody has an oven, so the only other things you would need are time, space, a strainer/screen maybe, and a tank and plants(maybe cheap fish) to test it on.
I would love to create something, or see it created, resembling aquasoil physically, having a granular form that allows it to hold its shape underwater and be piled into slopes and hills to create dynamic aquascapes. Chemically, it should be able to grow plants well, plain and simple. Humic acid is supposed to greatly increase plant health and soil is nutrient rich. Therefore, this part shouldnt be as hard as getting its shape right and keeping it that way underwater. The catch is doing all this at a low cost, not $30 a bag. There is potential to make a lot of money around here with something like this, but if you create a low budget aquasoil using something like whats described here and decide to sell it, I hope you will share the information and processes used to get there with your fellow aquarists.
Thank you and good luck.