The Planted Tank Forum banner
1 - 1 of 1 Posts

6,786 Posts
Hi All,

This is an interesting discussion. I have used Montmorillonite clay substrates for about four years now starting with Soilmaster Select Charcoal (discontinued), then Turface Pro League Grey (grey discontinued - other colors still available) and now Safe-T-Sorb #7941. In addition I use Walmart Special Kitty (non-clumping; unscented) as a cap for the Miracle-Gro for my emersed growth plant bank. I have also used ADA Aquasoil Amazonia. Prior to using the aforementioned products I used natural medium fine gravel with good results.

What I like about the Montmorillonite clay substrates is their ability, with their high cation exchange capacity (CEC), to absorb the nutrients I add to the water column and make them available to plants in the root zone. They are also inexpensive, typically STS #7941 costs me about $11 for a 40# bag.

Montmorillonite clay substrates are not perfect, all of them I mentioned are extraordinarily "dusty" and require extensive rinsing prior to first use. In addition they do effect water properties for several months when first used; they lowered both the dGH and dKH (and corresponding PH). I compensated by Seachem Equilibrium and adding bicarbonate of soda (baking soda) to raise the parameters to the levels I needed.

Since I like 2" -3" of substrate I have never had an issues planting unrooted stems; I just plant them deeper. Obviously the different Montmorillonite clay substrates have some variation in weight, I find STS #7941 to be heavier than most and comparable to ADA Aquasoil Amazonia weight-wise.

Natural Gravel

Soilmaster Select Charcoal

Safe-T-Sorb #7941

Emersed Plant Bank
1 - 1 of 1 Posts