Ethpool is not like a standard pool where you are paid every round based on your percentage of valid shares contributed. Instead on Ethpool you accumulate credits towards a full block payout and only receive a payout once you accumulate enough credits to be the first in line at the top of the payout list for the next block found by the pool. Once you reach the top, you receive the next full block payout of ~3 ETH plus an Uncle payout if it's an Uncle block.
It's more like solo mining but you don't lose credit for the work you did if you don't find a block, like you do with solo mining. You also have the benefit of being able to estimate when you will receive a payout by looking up your wallet address on the miner stats page. With only 3 GTX 1070's, it will take many months before you reach enough credits for a payout.
The OP may use Ethermine.org instead, rewards are fairly distributed to miners using a Real time PPLNS payout scheme so you will be paid based on the shares submitted with 1% pool fee upon reaching the minimum ether payout. for now standard min payout is 1ETH and is adjustable down to 0.05ETH.
https://ethermine.org/
