@lio78 @WhyMe

Unlike other kinds of cryptocurrencies, in order to mine tokens, you must send transactions, and they are quite expensive in gas. All in all, you'd need more than a few Ethers to run a pool for one month; and since we didn't do any ICO, nor our tokens have any price on any market yet, we're basically giving you this for free, at Catether Network's expenses 

So, the pool fees are the only thing that could, maybe, reimburse us; we will reduce the fess drastically once it becomes profitable to own a pool; until then, this is our only security. You can still solo mine, though, however you will have to pay for the gas

You don't have to specify custom diff, vardiff is enabled automatically and adjust to your hashrate