1 credit is 50 satoshi right? 150 satoshi - 500 satoshi / surf is quite less amount of bitcoin, i think it's hard to get member. Especially with high amount of minimum withdrawal
maybe you should lowering minimum withdrawal amount, and hopefully raise surf bonus in the future.
Good luck with your project
We set the 1,000 Credit Minimum as a baseline to ensure we weren't flooded with a barrage of Cashout requests on the off chance that we couldn't handle them all immediately. However we've reassessed the limit and have now lowered it to 200 Credits
Can you add more payment method, because I think it will be more easier for some people.
We're actually looking into adding more options right now, but we're trying to go with a service that is off the block chain in order to avoid transaction fees like Xapo.
I'm sure many user will interested with your program