70L, from my calculations is just over 18gals? (Sorry i hate the metric system)
That is quite a small tank considering the fish stock. The Cons will get really aggressive, might be a cause for color loss in the Parrots, and 1 pair will prob. end up dominating that tank.
If i were you i'd look at the stocklist and maybe rethink stocking. What works when the fish are young may not when they are older, in this case, i'd say it won't. The cons will just kill everything come breeding time.