What it boils down it is this... what type plants are you going to have? Low lightond easy plants like anubia, java fern, bolbitus, and maybe java moss all of which don't need to be planted in a substrate? Or do you want higher light with more plants actually planted in the substrate? Reason I'm asking is this... if you want a low light, low tech tank with mostly plants that attach to rocks or DW and maybe a few easy plants like crypts to put in the substrate then using plain sand or small sized gravel will work just fine. I don't recommend dirted tanks to newbies. If you want to plant a lot of stem plants then I would suggest spending the little extra bit of money and getting a good plant substrate like Eco Complete. Personally even if your going low tech for now if you use a good plant substrate like Eco it makes it very easy down the road to upgrade lighting and move into higher light plants or even carpeting plants. It all depends on what you have in mind. Here's a good link to look at small tanks and maybe to get an idea of what your wanting so you can choose the best substrate...
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