Storj works best when you don’t watch it too closely 
. There have been many threads where people talk about reasonable expected growth rates (example, example, example) - and one post yesterday where they got around 1.5TB in the last year. But the last 12 months have been abnormal: because there were a couple large purges of inactive/deactivated accounts.
Basically if you did see 70GB/day… if that held it would be around 25TB/year. Nobody is getting that from a single /24 - so expect to see space grow and contract. Every bloom filter is going to nibble some off: and the larger your nodes get the larger those nibbles become 