First, I need to say this. I've never been the most savvy guy when it comes to using my electronics fully...

I just got a boat that has a X70 and 520c on it. Admittedly, most of the time, I've got both on the auto setting. I get amazing images from the X70 but I can't figure out why lots of times I'll see massive schools of shad on my X70 and I'll see nothing on my 520. Sometimes I'll just see tiny and thin red lines on my 520 when my X70's showing tons of shad and other details throughout the entire water column.

There doesn't seem to be anything wrong with my 520. I've tried to tinker around with it, but I'm kinda starting to become stumped...

Did you try:
MENU, SENSITIVITY?

serious question, are you running both at the same time. Could be getting interferance on the 520c?

I have a 520 on the console and a 102 op front at the troll motor. I think you may be getting interfeence between the two. I think a ground wire could solve this. I really think you will have much better results running units on manual. But you will need some help with settings and getting use to this. I never run my units on automatic. Best of luck.

Okay, yes, I've tried adjusting the sensitivity on the 520. That didn't seem to help at all.

Yes, I'm running both at the same time. The X70's up on the bow and the 520's on the stern.

One thing I did notice about the 520 is that even tho when I checked the sensitivity when it was on auto - in deeper water, around 30+ feet, I wouldn't get a very good reading of the bottom at all.

One thing I haven't tried - could resetting the 520 help?

Your getting interference between the 2 units. when your not using the x70 turn it off and your screen on the 520 will clear up.

1. down load the latest software 2.5 in your 520
2. then put the unit shallow water mode
3. sensitivity 72-78 or auto
4. color line 72-74
5. ping speed 75
6. surface clutter and noise reduction on low.

Thanks man. And thanks for the following suggestions on how to set up my 520! I'll try all of the above suggestions.

I saw Jason's settings in another thread and then set both my 520's by them and they're both awesome now. I had never seen so much detail before. The "shallow water mode" software update probably helped too.

Thanks Jason!