Gravel Vrs Sand? How Anyone Tried Half And Half

I'e been thinking of trying my fish with sand... especially for the loaches who try to bury in the gravel.
But I also like having gravel for the others..
Can someone help me out with a pros and cons of both I guess.
Has anyone tried having both in the tank.... having say one half sand and the other half gravel...
Or would it be a Terrible idea??
I have 1 coldwater tank with goldfish, rosey barbs and weather loaches. And at least for now two cae.
And then a tropical tank with Guppies corydoras kuhlI loaches and three otocinclus as well as having shrimp and snails

 

I have a tank with a gravel base and two circles of sand, 1 black and 1 white. It works, but is hard to keep clean as the gravel starts to mix in.
ive also kept the sand and gravel separate with a large stone before

 

I like the idea of your second picture. That was a bit like the idea I had to do my tanks

 

If you were to go with both you could get a glass dish and place it in the tank. That way it’d be way to separate the sand from the gravel, I believe I’ve heard of someone doing it before.

 

My 10 Gallon has a bottom of Gravel with Sand on top with more Gravel on top of the Sand, The Snails like digging in it and the Plants grow strong root systems.

 

I have a 20 gallon long with sand in the front half of tank and soil topped with gravel along the back. Actually it’s 2 kinda of sand in the front; black and natural desert red sand. There is some mixing of the sand but I like the natural flow of the sands mixing. I will try to get a picture posted.