I agree with mike. Remember that ultimately you want to be even with or above the fish your marking. They will go up to hit your baits but will rarely go down if your well below them. Trolling speed will effect the depth also. For example, running your mag tadpole 148 back at 2.0 MPH will put you down to about 48 feet. Running the same set up at 2.5 MPH will only put you down to about 37 feet. That’s a big difference! So there’s a few variables to get yourself in the zone you want. Get the lifetime membership to the app if you can and you don’t have to pay for any updates after you pay the membership fee.