Planted Tank Guru
Join Date: Nov 2009
Location: Missouri united states
I used to take red potter's clay(iron rich) and place the prill's of osmocote inside and form a sausage if you will and then bake them or let them dry in the sun.
Then stuff em deep in the substrate.
Was not my own idea but borrowed from another member on another froum.
tore down a tank after a year with these little sausages and was surprised to see that they were still largely in tact.
Not sure how much more slowly this allowed nutrient's to escape if at all ,but decided to just sprinkle osmocote on very bottom when I reset the tank thinking the clay should have dissolved more that it had, and perhap's the benefit from the osmocote was diminished?
I just made substrate deeper ,and seldom see the little prill's work their way up but I do not have many fish that dig.