it's more a matter of personal preference. Assuming your base rock is essentially dead LR
with the same porosity as most LR
, it will become bio active in a few weeks fufilling the same filter function of LR
, then you don't need any LR
at all. If you want the beauty of LR
and the miriad of life (inverts and algae) that come on it then add enough LR
to be pleasing to you. A lot of folks use base rock to support the LR
when using a DSB
. In this case the BR is buried in the sand, the LR
is exposed. I have added pieces of dead rock to my LR
and in a matter of months it is fully encrusted with tube worms, vermatids, and coraline.
Your plan should work just fine.