Furthering plans for plant-filtered tank, would like feedback

Alright, so here's what I've got so far in my plans for a lo-tech tank.
I'm going to start from the ground up, and include any questions/requests that I have about things.

10 gallon tank.
Under-substrate heater cable. This is supposed to be better for plants, and it heats the water, so it does double duty. Has anyone used heater cables for their tanks? What rating should I get for a 10 gallon tank? I'm presuming the smallest wattage available, but am not sure.
Substrate will be flourite topped with black sand. The flourite is to provide iron for the plants, sand for asthetics. I'm going with sandy substrate because one of the plants I'm going to have does better in sand.
Primary plant in the tank will be micro-sword. It's a fast-growing, fast-spreading plant that will cover most of the floor of the tank.
Unsure of midground plants. I had been thinking variegated sweetflag. Drs Foster &Smith sell it as an aquarium or terrarium plant, and say it will indeed grow completely submerged, but plantgeek says that it will die if submerged. Does anyone know which of these is more true? If I can't do variegated sweetflag, I'll probably go with a leafy plant attached to driftwood.
I'm not sure what I'm going to do for background plants, likely something with feather-like leaves. Does anyone know of a good one that prefers being rooted to floating free?
I'm also thinking of adding a single marimo to the mix, just because they look neat.

For animals, I am going to start, I think, with a betta. They aren't a schooling fish, they're colorful, and, perhaps most importantly, if the O2 levels drop at night, a betta will still be able to survive (with no aeration, oxygen when the plants go into non-photosynthesis mode has been my biggest worry).
I'm also going to be adding at least one invert, probably a Japanese trapdoor snail. I had been thinking of putting a shrimp in, but that was before making the decision that the tank will hold a betta. Might replace that with a mystery snail. A different possibility would be a clam, though I'm unsure if it would do well with the microsword. Does anyone know if a freshwater clam would encounter trouble with the roots of a rapidly spreading plant?

Question regarding lighting. The tank I got came with a hood that has space for two incandescent lights. I got two of the compact florescent bulbs, one 50/50, one deep water. I'm unsure, however, if I should use both at the same time, or if I should only have one going at a time. The tank is only ten gallons, and each bulb has the equivalent of 50 watts of power.

This is what I have so far, and would appreciate any help/feedback I can get.
Thanks

 

hello there - just a few comments -

I would strongly recommend against the under substrate heater cable. plant roots will get all tangled up in it, and there hasn't been any real improvement shown from using them. you can keep the water heated with a regular heater or a submersible.

for the background - would something like cabomba work? I know it comes in green and red, but not sure if that's the look you're going for of if you want to deal with them.

if you go with a mystery snail, make sure you get a brig as opposed to any other kind. the other kinds will treat your plants like a tasty treat!

I used to have some clams, and they did fine. the thing with clams is that you need to make sure they have enough "floaties" - stuff just in the water column since that's where'd they eat from.

not sure about the bulbs. I just use the standard compact fluorescent in "sunlight" spectrum. how many actual watts is each bulb (not equivalent - I think most of the wpg rules are based on fluorescent watts)

gl on your tank!

 

Thanks for the feedback regarding the cable. I've got one book on planted tanks, so I've got kind of a limited scope of information. I want to make sure that the plants flourish, since they're going to be crucial to the health of the tank. That makes things much simpler (and cheaper, heater cables are expensive).

 

cool! let me know how your tank goes!

what plants/substrate/etc are you putting in there?

 

Substrate is flourite topped with black sand. Flourite provides iron to the plants without any nutrient additives, sand is for aesthetics and is good for one of the plants.
I'm going to be going with micro-sword as a grass-like base for the tank, and a marimo (Japanese algae ball) for sure. I'm not sure about background plants. I had been thinking variegated sweetgrass, as Drs Foster and Smith say that it's an amphibious plant, and can live either in or out of water. Plant Geek, however, says that it is a terrestrial plant only, so I'm trying to find out more info on that. Otherwise, I'll probably do a couple swords or other plants that like to be attached to driftwood.

Edit: Griffin, you said you had clams before. What did you do to feed them? I see there are a bunch of marine foods, but none made for freshwater. Does it matter?

 

I don't know if it matters, except that the clams I had were much smaller than any of the marine clams i've ever seen. mine ranged from about 0.5 - 1 inch length. I didn't really feed them directly, but I would put in some extra fish food (ground up - similar to fry food). i've also heard that liquid algae (not really sure what this exactly is or how to get it) are good things to feed. basically, they filter food out of the water, so it's better for established tanks, but I think if you just got a few, they'd be fine. let me know if you decide to go with them.