Setting chart display parameters on Raymarine RL/SL70/80

[ZZ13]

I have a Raymarine SL70CRC (early 2000's technology) I've used for the year that I've owned this boat. I just can't figure out the depth display settings. Best I have been able to figure out is that it will display 3 colors for depth. White for really deep stuff, light blue for medium deep stuff, and medium blue for shallow stuff. The manual doesn't help with this. There is something called a "depth shading limit" I can configure that lets me pick from, 0,3,7,10,16,33,66,98... for depth. By trial and error if I pick "0" then all depths are shown in white. If I pick anything other than zero then it shows depths up to around 16 feet in medium blue, and most everything deeper than that in light blue. But it does show depths in white that are really deep (like hundreds of feet deep). Does anyone who still uses one of these have the handbook on how to use that parameter (or the other parameters) to set when these three colors appear? I'd like to see a color change at the 3 or 7 feet mark, but I can't seem to make that happen.

Also, what does the "chart boundaries" setting do? My display doesn't seem to change whether I set it to "on" or "off".

Thanks.

 

[ZZ13]

After doing some more reading it appears the water should display as white when the depth is above the setting for "depth shading limit". This is essentially the depth safety setting. So today I tried it again and lo and behold it worked as I expected (not sure why it didn't yesterday). I set the parameter to "16" and the depths over 16 feet showed up as white. So most all of my boating area will be displayed as white. This is much more desireable for my old eyes than the light blue. Probably will save delay me spending $3K in an upgraded electronics package for a few more seasons.