Which substrate? Opinions, please

[WhistlingBadger]

I'm thinking about redoing my 55 this coming summer, and among other things, replacing the crushed granite pea gravel with a darker, more plant- and mouth-friendly, easier to keep clean substrate.

These two are on Ebay right now, and they're about the same price once you figure shipping:

Lava rock. I asked, and the guy told me the particles are screened to 2-3mm, so it's more like really course sand, which is really what I want. Not sure about the chemical composition, but the color is nice and natural.

Black beauty sand. I realize this stuff is actually iron mine slag, and some say the remaining iron is good for plants; other say not so much. Very fine consistency, which I have read is not as good for plants, but it's easier to keep clean because debris collects on the surface. Seems to look more dramatic, but less natural.

Opinions? Experience? Anything I need to know?

Thanks!
Tom

[ScottishFish]

I have read in a few books that you need to be careful with what fish you stock if you go for crushed lava rock, it can be very sharp and abrasive. So Barbled fish like corydoras can hurt themselves, also burying fish like Khuli loaches as they may scrape their bodies.

[WhistlingBadger]

No corys right now, but that might change. Something to consider. The particles look rounded, almost as if they've been tumbled...but who knows. Thanks for the suggestion.

Oh, by the way, buying the more expensive, commercially available gravels (Seachem, et al) isn't really an option. Since money is an issue, as always, I need to go cheap, here.

[Fishisompin]

Substrate is very important! It changes your water quality. Many beneficial bacteria--that keep your water fresh live there--Don't go cheap...its best for the long run...for fish and keeper...

[Lady Hobbs]

Flourish sand? It's black.

http://www.marinedepot.com/Seachem_L...FWPCPG-vi.html

[toddnbecka]

Black beauty is coal slag, not iron slag, and is completely inert. The same thing is sold under the name black diamond by another company, it's actually sold for blasting grit but works just fine as an aquarium substrate. I got some locally, paid $8/50lb bag. It won't do anything for plants, essentially the same as sand except there's no silica to support a diatom explosion when you put it into the tank.

[WhistlingBadger]

Substrate is very important! It changes your water quality. Many beneficial bacteria--that keep your water fresh live there--Don't go cheap...its best for the long run...for fish and keeper...

I understand that...It's just that my family has this crazy idea that they need groceries and medical care. :)

[WhistlingBadger]

So, looks like the lava rock is a no-go. Too tough on my bottom feeders. I'll probably try to find some black diamond locally and go with that. OK.

I've always used gravel, so a couple more questions: I've been doing some more reading. Seems the main (only?) disadvantage of sand is that it can get stagnant because the water doesn't circulate through the finer particles. So, you keep it fairly shallow, less than 3", and that isn't a problem, right? This is a 55g planted tank.

Would it be wise to add a few kuhli loaches to keep it stirred up, or does it matter?

Thanks, as always!

Tom