I think he has one.

 When going for dhues deeper water try this. Range 30 feet ( or 10 meters). Then use shift button until you pic bottom up. Gives you a heap better reading of the area where fish are. Bottom dis mode( high) is fantastic for picking up fish. Also small ledges. Exposes fish brilliant.(split screen). Basically is a bottom lock takes all wave action out of your reading. In setting set the noise reduction on ir2 if you go to high you will miss out on seeing certain size fish. Gain or sensitivity 3.8 to 4.0 . That covers you to 100 m mark. Any deeper increase accordingly . In your colour pallet you can have your standard settings light blue dark blue black vivid ect. I don't use any .customise  your colours by increasing or decreasing them. I use white background with extra red yellow and blue for fish and bottom colours. These few things make th a lot easyier to understand bottom and fish. You can pick up your lead going all the way down no probs. if your p66 set correct ( flat) not angled forward or backward. Book is very good reading . There not a crap sounder . Not as good as furuno but there up there in my books. Once you set them up that's it just alter range and gain . Shallow water(60 feet) or less just use full screen mode. Picks up pinks mullys ect no probs at all. Hope this helps a bit. Cheers tomo

 Thanks for your reply!

 I went out today with my brother and tested the sounder out. We played around with a few settings and pretty much ended up with similar settings to what you have suggested so thanks for that! I run a new furuno 588 in my boat but for 1/8th the price this ff50 is really impressive! We found some new ground and bagged out pretty quick so no complaints at all! I'm surprised not more people use these units