Trickle Filtration vs Canister Filtration

Are these true?

1)Trickle filtration method will cause quick oxidation of iron.
2)Use alot of CO2
3)For planted tank, canister filtration is better than trickle

I have referred to George writeup on his SST where he used trickle
filtration. And there was no complaint about quick oxidation of iron.

But hoping to get a general opinion from the public.