If you want a small reference on the black...do exactly as gumbii said, make absolutely freaking sure you get CLEAR silicone. My freaking dumbass browsed the section for 20 minutes with this in mind and somehow managed to STILL grab the wrong ones. At least it was Silicone 1, but white.

Coated PVC must be all the rage now, I just did mine for my new tank last week:
http://icedt83.spaces.live.com/photos/c ... 46FF0!149/
(under 'new fishtank' album)

Substrate is blacksand flourite, the PVC is coated in Tahitian moon sand (black) and because I used white silicon I threw some loose substrate on top of that...

Also do your thing in sections, little by little, if you have the time or patience. It seems that in some cases it was curing too fast which made it easier for the stupid sand to fall off as I was coating it.

Lastly now that I'm looking at this picture again...most DIY sites say that its fine to just do the 'lips' of the PVC, well if you look at mine..since the PVC is white and the sand is black well...I guess you can say I'm probably gonna be taking it out someday and starting the 3 day process of drying, coating, curing, and rinsing again. =P

Tmerc---

Wow, I really like the PVC you made. That is very cool. And with a dremel tool I think I can make it look like driftwood by roughing and shaping the ends, creating irregular striations, and even knot holes or rises (where branches were). It looks good and I've got black substrate, too. I've out of town right now but can't wait to get back to my fish...

Zambize

Although people say don't use the silicon II, I used it for my pvc after realizing it wasnt silicon I. I have had it in my tank for a couple months now and all seems well, my fish are healthy. I still would not advise it though, if you can get GE silicon I. It's the same stuff you but in an LFS that's branded "Aquarium Silicon" for 10 frickin dollars.

Speaking of projects and aqua-scaping i've scored a lot of nice shale for my tank from a jobsite that snowboss and I are working at. I'm going to build a nice rock wall in the back of my tank and fit the pvc nicely into it. I have to rinse it off still and i'm worried about stressing my fish with such a big change.

Tanks for comments and a1, if you mean the tank in my profile its broad-leaf watersprite. The 30 gallon I linked to above currently has no floating plants, but has onion plants (like yours) that stretch to the top along with corkscrew val on the right side.

Z: I acutally purchased my first dremel just to do this project. It's VERY effective..got the new lithium ion 10.something volt. I guess that part doesn't really matter I'm sure all dremels work great. I think boss has the right idea if you're gonna do some mad sculpting, give yourself a bigger canvas. Or you could actually build layer upon layer of silicon (letting each layer cure in certain areas to achieve desired effect) and coating the top with your substrate.

I actually sawed through the bottom 1/4" creating an open bottom which was pretty time consuming. lol I figured this way they would always have soft, dark substrate under them, and I wouldn't have to worry about coating the bottom inside of the pipe.

I did mine in a hurry and from cut to last grain of sand it probably took 5+ hours...and mine didn't really come out that satisfactory, so be ready to spend a little time. :)

Yeah, I've seen some really cool backgrounds with cement. However they raise your Ph through the roof. Cement should only really be used with new tanks that have no fish yet. I read one article not too long ago about this guy who made a background with cement and had to do like 70% water change every day for a couple weeks and Ph buffer to get it down.

Sounds like a real pain in the ass to me but you can make some crazy looking stuff with cement.