It seems the cause of the problem is Core 0.12 nodes and miners not relaying valid transactions, causing the mempool to expand.
I'm banning all 'classic' and XT nodes as transactions sent by those spammers are not valid transactions. They are altcoin promoters.
as of Core 0.12 you don't need to bann them, Core has already set the defaults for you.
turns out it's not only effective for all 'classic' and XT nodes but all core nodes running 0.11 and below. Yes obviously its just Core0.12 that's correct every other node is spamming the network.