In my final month I lost $600. I didn't include this on the chart to keep things simpler visually. Since then I have not traded and the reason is that it was abundantly clear that my program was no longer working. That's why I shut it off.

With regard to tuning I may have lost $1000 or so but as I wrote in the article I was able to build a backtesting model that accurately simulated live trading. So once I had that I could basically use it to verify I had sufficient edge to make a profit after covering my commissions.

My risk exposure was very low. When I said large losing positions this meant like $600. But the bottom line is I had a daily stop loss of $3000 enforced at my broker. The most I ever lost was around $2000.

Anyway, there is not really some hidden thing that I am not telling people. It does bug me a bit that your comment is at the top given that it says I'm manipulating statistics and was actually one of the guys that the quants gleefully picked off. I think it's unlikely I traded much with other HFT systems but if I did they certainly lost money.