Is Craftsmart Natural Clay safe for aquarium use?

[MadTurtle]

So I just bought some of the Craftsmart Natural clay from Michaels to make DIY root tabs. I am mixing it with some organic potting mix, rolling into balls, and letting it air dry. I am probably going to bake it in the over for an hour as well. I am having a hard time finding any information online about it, other then the product stating that it is 100% natural and non toxic. Has anyone used this clay in their aquarium or know if it would be safe to use? 🤙🏻

[gardenman]

Safe to use, probably. The issue you may have is the clay trapping the nutrients inside the clay. The "organic potting mix" could be an issue also as potting mixes are typically made using peat which can acidify your water. (Not all and there's a move away from peat, but many mixes still use a lot of peat.) Clay can be quite effective at sealing out moisture which could trap your nutrients away where the plants can't get to them.

[MadTurtle]

I thought clay was a good source of minerals for plants? I just filled a glass with gravel and pushed the tab to the bottom. I won’t be using them in gravel, but I had some lying around. Mine will be pushed to the bottom of a 1 inch layer or topsoil, capped by a 1-1 1/2 inch layer of BDBS. Within 30 minutes it had basically disintegrated Isn’t that essentially what it’s supposed to do? Wouldn’t the minerals then become absorbed by the soil for the plant to use? I am brand new to this, and just trying to learn.

[Seattle_Aquarist]

Hi @MadTurtle

Not all clay is the same, there is a huge variation in the amounts of various nutrients depending upon where it is sourced.  Most clay materials have a high cation exchange capacity (CEC) which allows it to absorb nutrients and making it available to plants in the root zone.  As you noted regular clay breaks down very quickly, I prefer to used calcined montmorillonite clay which is a heat treated product.  It makes the clay much harder and much slower to break down.  I either use it by itself (I like Safe-t-sorb 40#@$6.49 at Tractor Supply).  it has a nice natural color and does not have sharp edges which can cause issues with the barbels of Corydoras.  I just add some Osmocote Plus size "00" gel root tabs near the bottom glass whenever the plant growth starts to slow down.  Since the water column has minimal nutrients in it I have very little issues with algae on the plants, glass, or hardscape.  Here is a thread that I did from start to after several months.  NOTE:  the thread used 21 tabs for a 45 gallon tank and was too many, I recommend more like 1 DIY Osmocote Root tab per 5 gallons.  -Roy
https://www.plantedtank.net/threads/a-45-gallon-high-a-saxa-tilly-inspired-tank.1301089/#post-11283643

[Gideyon]

@Seattle_Aquarist, how did you rinse the clay?   I've been looking into this for an experiment.  I only need less than an inch  spread across a 10 gallon.  Sadly I have to buy 40 lbs just for that much.

But I've been reading stories of how hard it is to rinse.  Just curious to your experience.... 

 

[Seattle_Aquarist]

On 7/27/2021 at 11:09 AM, Gideyon said:

@Seattle_Aquarist, how did you rinse the clay?   I've been looking into this for an experiment.  I only need less than an inch  spread across a 10 gallon.  Sadly I have to buy 40 lbs just for that much.

But I've been reading stories of how hard it is to rinse.  Just curious to your experience.... 

 

Hi @Gideyon  I used to sift my Safe-t-sorb (STS) to remove the 'fines', then 'load; the STS with nutrients, then do three or four rinses.....what a huge PITA!!  lol

So a few years back I tried doing it a different way.  I just pour it straight from the bag into the tank, contour it, add my hardscape, then cover an area with wax paper with a dinner plate on top.  Fill with hose slowly so as not to disturb the substrate.  Here is a thread with pictures on another forum where I show how I did it.  It lasts about 2 years and then since it is so cheap 40#@$10 just throw it in my garden bed as a soil amendment and use new.  Hope this helps! -Roy

NOTE: I did cut back on the number of DIY Osmocote Plus root tabs to one (1) per 10 gallons after this attempt caused high levels of ammonia for several weeks.

[Gideyon]

That looks nice as a substrate.  I may consider this instead of black diamond blasting sand.  I was imagining it would be gray and I would top off with bdbs.