Adding substrate?

It should be okay as long as you are only adding enough to cover some roots. There is a trick to adding substrate to your aquarium using a 2 liter bottle so you don't make a huge mess, there are some good youtube videos out there showing the method. Depending on the size of the aquarium will really depend on how much you can add. If you wanted to add a lot you can easily wash the substrate, put it in a 5 gallon bucket with established tank water and a power head for a couple days, change 50% of the water and replace with tank water and let sit for another two days. This will kick start your substrate and make it "live".

Awesome. Thanks! I only have a 38G, so I really wouldn't be adding very much, maybe 8 cups at most. Would that really be enough to upset the bacterial balance?

EB

It should not upset the balance with what you are adding. If you are worried about it you can always mix it with some established substrate and that will help the bacteria colonize the new substrate.

Only thing is, I don't really remember what I used for substrate...Anyone care to try and ID it from my tank pics??

The amount of bacteria in the substrate is pretty negligible compared to what's in the filter media.

That waterbottle method works pretty well for flourite, I've done this exact thing before. If you are using sand, you'll need something with a smaller opening. Another plus is that you don't need to wash it, pretty much all the dust/cloudiness remains within the water in the bottle. It's also great since the substrate grains sorta 'rain' or 'sprinkle' down and spread out a bit, so it works really well for this sort of thing.

I wouldn't bother with any prep work, stick some in a bottle, fill it with water, and sprinkle it out where you want more, remove empty bottle with cloudy water, repeat.