Substrate?

I have a variety of different setups, and here are some that I have had success with.

Eco-complete by Carib-sea- dark gray/black substrate, doesn't compact, excellent source of nutrients for root feeders, one of the best I have tried. Can be added directly to the tank without rinsing and won't cloud the water

Flourite by Seachem- reddish clay colored with bits of brown and black. Excellent source of iron btu can cloud water if not rinsed thoroughly before adding to tank. Can be mixed with other substrates 50/50 and still yields excellent results.

Play sand - can compact and become anaerobic which prevents root growth. Nice color and easy to use. Usually requires extensive rinsing prior to use, can also damage barbels of bottom feeders.

Peat moss/organic matter - one of the most difficult to keep for me. Lowers hardness of water, stains the water a deep tea color. One of my favorite tanks, but by far the most difficult to maintain as mulm accumulates and is very hard to clean until the leaf litter and peat settle out. Can create extremely low pH and a serious pH crash if your water doesn't have good buffering.

My personal favorite tank is a bottom layer (1-2 inches) of eco complete covered by an inch or so of play sand. The resulting digging and plant moves has caused a mix of dark/sand and I have added small groups of tiger's eye (quartz) cobbles to add some character.

Play sand will work, but as said before it may become compacted and that will create anaerobic spots in your substrate... not a good thing. It prevents root growth in those areas, and if its distrubed, it may release nasty gases into your water, also not good. However, if you keep the sand stirred, and your plants have good root growth anaerobic spots can be prevented. Though it does look nice, some people have problems keeping plants rooted down. I tried it before in my 15 gallon with success, but I don't think I'll be doing it again.

I wouldn't suggest an organic substrate, there's just too many nutrients in them, and it will most likely turn into one big headach. In fact, in many planted tanks, its suggested that parts of substrates should be rebuilt every now and then (ie. removing excess organics from the substrate) to prevent old tank syndrom in a planted tank. Advoid this substrate, especially if you're a beginner.

All of my tanks use Seachem substrates, whether its flourite or onyx sand. Onyx sand is a bit rougher with a larger grain than your usual playsand, but it seems to work just as well as flourite, it doesn't compact, and its a nice colour (dark grey/black). It can however, raise the KH of your tank slightly. Flourite as mentioned before is also a very good substrate, this is the substrate I'm currently using the most.

I suggest dusting the bottom of your tank with a very thin layer of peat moss. Cover that layer with the mulm you suck out of the gravel in a healthy tank, then cover that with flourite. That should give you a pretty decent substrate to start out with.

HTH
-Richer

Agree w/Richer. Good, sound program and advice.

I second that I have 2 tanks with onyx and getting the urge to do a third this time with eco-complete just for a change.

I use Schultz's Aquatic soil (aka Profile) in all of my tanks. I really like it. Things grow great in it and it's available at most home improvement stores or aquatic landscapers.