You're getting approximately 31.6 Mh/s per card? What cards are you using please?
How's your power consumption?
i'm not the TO - was just a rough calculation based on experience - with one MSI 1070 X 8g you can have ~ 30.5 MH/s so with 10 Rigs @ 6 Cards each you have 1830 MH/s and it'll use then ~ 7,5-8 KW.
with RX480/580 it would be even cheaper from pure investment on hardware and they should also be able to handle 30.5 MH/s per card.