I have been using in all my planted aquariums DIY substare, and I have a nice recipe for it, I get almost as good results as ADA..
I know alot of people who use DIY substarte in big systems, if you look at a 500L tank then you are looking at about 60-65 kg of ADA and that is damn expensive....
if anyone has any ideas or improvements please add your comment
well here it is:
10% -red dirt(its called "hamra" in israel)
you boil the humus in hot water for 2 days and you let it sit in water.
you put the "hamra" in the oven with max heat for about 2 hours.
then you mix it all together and add some active carbon and osmocot to it.
on top of this layer you put another layer of quartz or any othe inert stone, and when I say quartz I mean scrunched quartz...
and thats it.