The arbitrage with arbitragepros seems like a very simple and straightforward tool to use, but in reality, this method can be fully utilized by a large trading accounts only.
The real profit from the arbitrage trading depends on the commission the exchange is taking from you for withdrawal. In general, you want to get at least 2% of the difference from each arbitrage trade you make.
Let's drop it in a real case for better understanding. We have used an account worth of 10,000 USD to complete the arbitrage deal between Bitfinex and Kraken exchanges (half funds in fiat and the other half in Bitcoin). The average gain from the trade was 2% and it has given us a 100$ of income.
When we initiate a fund withdrawal, the Bitfinex takes a fixed 40$ as a fee which reduced our real net gain to 60$. Now we need to send all of our money back to Kraken and purchased Bitcoin to Bitfinex in order to repeat the arbitrage transaction. This is why this method is best for the accounts with value above 10,000 USD.