How do I interprete the bottom on a Lowrance fish finder?

I've been interpreting how solid the bottom is by the color on the display but just read an article suggesting that the colors for a hard bottom and a sandy bottom are not what I thought they were.

It's a wonder I've ever caught a fish, isn't it?  Must be dumb luck.

What shows a hard bottom and what shows a sandy/porous bottom?

This may sound incredibly obvious (because it is), but try tapping a weight off the bottom and get a feel for what it is compared to what the screen is telling you. 

Excellent advice, and I would surely do just that if I used anything other than a fly-rod.  When you get a nearly weightless fly, a fly line, and a long leader involved, all you can tell is your line went slack.

Nonetheless, thank you.  Setting snarky fly-fishing elitism aside, I suppose I could just swallow my pride and take a real rod-and-reel out to figure it out.  If I don't put a hook on it, the Lords of Fly-Fishing might let me get away with it.   

If you are only fishing on the surface, why do you even care what the bottom is made of?
 

If you are only fishing on the surface, why do you even care what the bottom is made of?
 

Wash your mouth out with Ninkasi!  I regularly fish 30-40 feet down with a fly and fly rod, and occasionally to 60 feet, and someone fly fishes to 90 feet.  It just takes a bit of patience.  Check the video YippieKaiyak posted (http://www.northwestkayakanglers.com/index.php?topic=19383.0).  Rockfish on the fly is like rockfish on ultra-light gear, but funner.

On the surface?  Saints preserve us!  [Mutter] [Sputter]   

I found this on a New Zealand website:

Lowrance display colours:
 - WHITE is no echo return
 - BLUE is weaker than RED
 - YELLOW is the strongest echo return

Unless anyone else knows better.

So, does knowing what the bottom is comprised of change the results of fly fishing?

Your original question was merely trying to understand what the screen is telling you.  I gave you a very simple procedure to easily validate what you are seeing on your screen.

For some reason you inserting stuff about fly fishing. 

What is the correlation that I am missing?

Does your display not show schools of said fish you plan to target?

I, for one, can't seem to see anything but bottom depth on my sounder.  That's still a ton more info than I would have without.  The gps, as I found out in the fog, is also super handy (essential, and I need a backup).  I've had a few moments where I can see fish (I think), and a few moments where I think air must have gotten into the scupper hole (or I'm bait for a zombie whale).  Depth itself is still a huge factor, but I'm sure I can improve on my skill with the sounder with practice.

Fly fishing or spinning or casting makes no difference, so far, at least to me.  I'm obviously no expert, as my biggest ling to date is like a barely legal 23 inches, but I do know what bottom feels like on spinning and casting gear with weight.  I'm a salt fly newb, so I don't know what the slam bam is like on the bottom because the fly weighs relatively nothing, but you can definitely feel the slack (also, don't set the hook 'cause its different, because, well, snags... *sadface*)

I would love to know, however, what the different colors/frenquencies/etc all mean other than "something's probably bottom down in them thar parts".  So far all I've found useful outside of the depth gauge and gps is the occasional half depth school of, obviously, fish.

So, does knowing what the bottom is comprised of change the results of fly fishing?

Nope, the bottom is the same regardless of the gear, and I meant only that I can't use fly gear to drop a weight to the bottom as you suggested.  I depend on the finder.

The last time I fished the Coquille River, I wasn't getting returns off the fish - no fish arches on the display - although I was catching them.  I made adjustments to the Lowrance's sensitivity, ping rate, water depth, surface clarity, broadcast frequency, and noise rejection to try to get consistent fish arches and couldn't dial them in.  There was no apparent correlation between bottom contour nor objects on structure to where I was finding the fish so I came up with the idea of trying to find out what kind of river bottom they were hanging around.

Bottom consistency isn't an issue for me in the ocean, but it's a good thing to know when chasing resident fish in the lakes and rivers - and that's why I had questions about what the finder is telling me.

I'm not dis-ing the technique you suggested, I'm only replying that it isn't a practical method with fly gear (and I added a bit about not fishing only on the surface).

 
 

So, without dissing my technique, maybe take  a spinning rod along with just a weight attached and do a reality check on the bottom to correlate to what your screen is telling you.

Then put that rod away and go back to fishing with your fly rod, until you experience a change in bottom colors again.  Then bust out the spinning rod again to see what it says.

Do this until you have a good idea of what the diff colors are telling you.

A spinning rod in a fly-fisher's hands...  Sorry, I couldn't resist one last time.   

I think it's an excellent idea, really, and I still have a good, short (easy to stow) spinning rod in the closet.  I'll give it a try.

I can't recall exactly which color is which but there is a difference in the colors generally the "darker" the color the harder the bottom. Not sure that makes sense. Look at the manual or an online tutorial they will tell you exactly what each shade means till you can't remember anyways(my case).


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Thank you.  The closest I've come to finding that information in the manual or online is a single post telling me that for Lowrance finders, YELLOW is the strongest return (hardest material) RED is next, then BLUE, and finally WHITE means no echo returned.

The tutorials I've found are more about "What does this lump mean?" than about how to relate color to the strength of the echo.

I just found this online: "Lowrance sonar units display echo strength in colors with yellow being the strongest and blue the weakest. The bottom is also displayed as a band; the thicker the band, the harder the bottom. Rocky bottoms will be display as yellow and have a thicker band compared to muddy bottoms."  Which isn't entirely consistent with other pearls of wisdom I've found.

I'm still going to put in the time doing what INSAYN suggested and drop a weight to the bottom until I know what the colors mean.  I guess there are no shortcuts this time.  Rats!

Another possible option is to call Lowrance and ask someone exactly what you are trying to find out.

Contact Us
If you need to speak with a Customer Service agent, please call our toll-free Customer Service line at 1-800-628-4487. Technicians and representatives are available to help you Monday through Friday from 8:30 a.m. to 4:45 p.m. CST, except holidays.

Or if you are skeered to call, maybe use their Contact Us page itself and ask 'em? 
http://www.lowrance.com/en-US/Contact-Us/

Now you come up with a simple(ish) solution?  After I dug that spinning rod out from the back of the closet?   

Sure, I'll give them a call.  But I'm still going to dust off that darned rod and use it to drop a weight.  Nothing beats practical knowledge.