I got only 8 satoshis, didn't receive extra 8 satoshis.

It will take a long time until reach 1000 satoshis to cashout... Especially claiming 8 satoshis every 15 minutes.
I think if you don't pay directly to FaucetHub.io after each claim it will be harder to get users to your faucet as people are avoiding threshold faucets fearing to be scammed.