Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Turface will remove the KH from the water. Keep a close eye on that. Test the water before adding it to the Turface test tanks. Then continue to test it, and if you add baking soda or other material to raise the KH.
The pea gravel looks a lot like the inert gravel around here used in the landscape industry. Not very good for plants, though. No cationic exchange capacity.
I like the looks of the darker turface.
I use these without rinsing, just being careful to fill the tanks without stirring the substrate. Pour the water in slowly over a plate or plastic bag.
Your father is right. "Aquarium gravel" is way over priced.
You can collect your own if there are areas of gravel 'just lying around', but I would test for GH and KH.
Landscape supply and masonry supply will have many types of gravel a lot cheaper than 'aquarium gravel'. The problem with any gravel is that it does not hold the fertilizers so there is no buffer, no reserve to stabilize the supply to the plants.
Mineralized top soil, Turface, Aquasoil and similar items are much better in a planted tank.