Dissenting opinion on the sand.
There's a difference in substrate between something that has nutrients and something that has the ability to absorb nutrients added to the water column. Eco Complete has the latter, something like ADA Aquasoil has the former. Sand, meanwhile, has neither, which is why it's not a great choice for planted aquariums. It also has the potential to go compacted/anaerobic, which not just looks nasty (like rotten black veins against the glass) but is also potentially toxic if disturbed.
Most plants will do fine on sand if you're also fertilising the water column, but it's not an "ideal" choice.
(FWIW, I put sand in my 10g fern jungle. The plants do great but… ugh. Went out and invested in Aquasoil for my next tank. Much easier to use, IMO.)
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