How and what should I use for a substrate for a freshwater aquarium?

all flourite is fine, iron enriched substrate that will help the live plants.

Unfort you will need to add to it or replace it every year. Peat moss is best in the filter, it will stain the water and lower the ph so im hoping your keeping south american fish.

I am not a fan of layering because sand in general is a pain to clean and remove and it will end up mixing and making the tank look bad IMO.

You also might want to upgrade the lighting if you dont want a CO2 system. freshwater powercompacts with two 6500K will do wonders for the plants.

One advantage of sand is that the crud (fish poop) sits on the surface, makes it easier to clean up. This is why you see more of it. With a gravel bottom it sinks out of sight and you have to dig it out with a gravel vac. The substrate wont change the amount of poop, just how easy it is to see. If you have a good filter system then most of the bacteria live in there, on a small percentage will be on the substrate, so it wont make a big difference. Ian Ian

I would recommend a good plant substrate covered with a deepish layer fine gravel. Avoid using coarse gravel as this prevents penetration of the roots.

Also you have to be aware that the more lighting you have, the faster the plants will photosynthesize. This will in turn increase the consumption of CO2 to the point where the plants will strip the water column of any remaining CO2. Unless you inject additional CO2 the plants will die.

of you really want low tech use play sand from home depot. i run 2 55w lights over 55G with just sand as a substrate. i have never needed to spend a lot of money on substrate as long as you dose the right nutrients

Here is a reccomendation

Flora Base

http://www.drsfostersmith.com/product/prod_display...

get one pound per gallon in your aquarium, and make sure it is at least 1" high if your going to put live plants :]