I think its just a contaminate of a different grit of the same material. The bag I have has it.
Thanks Immortal1 , I put enough worry/thought into it...lol The company says it is clay from the coal and I picked some of it out and it seems to be clay . I can crush it with pliers pretty easy and it looks like clay under low magnification . You are the mad scientist , so how can it be tested to see if there is any benefit of the clay as far as nutrient cation is concerned . I think I got that right...lolComing in a little late on this - I would guess there was some contamination resulting in the light colored pieces. For what it's worth, check out this site. They are a company that I do business with locally but I suspect their products are available nationally. My guess is the Coal Slag (Black Beauty) is what we call / use as Black Diamond Blasting Sand. Nice thing about this site is you can get different grit sizes. Pretty good method you have @Leeatl for making the switch out.
Don't worry, two weeks and someone will ask if this substrate is safe for bottom dwellers. It might even be me :surprise:I just turned on the overhead room light to check on the tank and all the cory cats are on the side with the BDBS....lol Guess that solves the " is BDBS safe for cories " question once and for all....lol
but isn't clay generally known for iron content? too bad there isn't a convenient and economical way to check for iron in a form that can be used.Well @Leeatl, "I can crush it with pliers pretty easy and it looks like clay under low magnification . You are the mad scientist , so how can it be tested to see if there is any benefit of the clay as far as nutrient cation is concerned . I think I got that right...lol"
I gave it some thought and this is what I could come up with.
Collect and measure out 1 gram of the clay material. Soak it in 5 grams of h2O for 30 minutes. Then add 1 gram of KNO3. Thoroughly mix the solution, preferably with the wifes mix master.
Then extract 5ml of solution and test with the API KH solution. Each drop will equate to 1 unit of cation. What you are looking for is something greater than 10.....
Common, I can't be good at everything, LOL