I like your tank, simple and small makes it easy to care for and my favorite is my nano 2.5 gallon just for that reason. When you get a couple dollars in your pocket you might consider buying a 9 liter bag of Aquasoil and it will feed all your plants plus you'll have enough left over to do a couple more small tanks, I've only tried it for the first time in the last year and I'll never use any other substrate again, good luck.
I just bought a bag and plan to use it on my next tank (in the mail) - I will rescape this spec V some day and get a quality substrate in there... eventually
You can put a small heater in the pump well.
*tries not to want a dwarf crazy*
they are a lot of fun