Hmmm I wonder why your sand made it cloudy. Did you rinse it out beforehand? Was it random play sand or pool filter/aquarium sand? I used black aquarium sand and it only started getting cloudy later because of tannins and a bacterial bloom. Oh also, did the gravel keep the soil down fairly well? I don't have experience with it but it seems like the soil could creep up because gravel can't compact as much as sand.
To givemethatfish: I think next time I do a tank I'm not going to use dirt. It's just too messy even with sand. I tried getting all the big chips out but there's still some coming up. And the soil I used came with little seed hulls that keep coming to the surface. Plus I think without a layer of dirt the substrate will be less thick and I won't have to poke it every week and worry about anaerobic bacteria gas pockets. I mean it looks fine but meh. I'm still experimenting with all this though and my tank has only been set up for a little over a month, so maybe in the long run I'll find dirt is better, who knows.
First go round was regular play sand, not rinsed, and that was a disaster. ;) Second attempt was with rinsed pool filter sand, rinsed...but still the mess. I did not know about using the plate or the paper towels though, so that may have made a significant difference. :P
As for the gravel, I wasn't sure about that either, but I found many, many videos on youtube from experienced aquarists who were using it, some even using pea gravel...and it worked, so I thought I'd give it a go. :)
I've only done this one tank so far, the other four are still as-is, I'm waiting to see if this makes a significant difference in plant growth...and is worth it. :)
Also, I believe trumpet snails can be used to aerate your soil if you don't want to poke. :)