aquasoil and ammonium

[killitex]

If you have aquasoil as a substrate and cover it with sand as a top layer, will the ammonium build up under the sand? And if you disturb the top layer and the ammonium releases, would that create an ammonium spike that could be deadly?

[Sea-agg09]

The problem with multiple substrates, is that the finer will eventually sift through the course stuff and end up at the bottom.

As a rule, natural nitrifying bacteria live in the sediments, and do most of the converting of ammonia into nitrites and into nitrates.

[nacra99]

Do take note that fresh aquasoil will cause an ammonia spike anyway.
IDK why they put ammonia in there, maybe its unintentional, maybe its to jump start the cycling process, who knows...

The bacteria that converts ammonia to nitrItes and nitrAtes are mainly aerobic (they need oxygen) and they live mostly in the top 2" of substrate. Anything lower and you run into anerobic (no oxygen) conditions, where ammonia is not readily converted (or converted extremely slowly) and some amount will most probably remain sealed away down there. IMHO, the best thing to do if you want multiple layers is to lay down a 2-3" layer of aquasoil and then allow the tank to cycle fully to allow the initial ammonia that came in the bag to be removed and then cap it off with another layer of some other substrate.

Also, note that if you have multiple distinct layers, you really only want to mess with the top layer (really only the top 2"-3") when doing vacuuming or maintenance. If you go messing with lower layers, then you'll start messing with the anerobic layers and then i suspect that ammonia will be the least of your worries compared to fart gasses (SO2) coming from within, which on occasion can also be deadly. Which is usually why many SW aquarists with Deep Sand Beds (DSB) never mess with it.

[killitex]

Thanks for all the replies, I appreciate them. Can you tell me more about the fart gasses? I bought some manzanita wood at HAW a couple of months ago. First of all it took forever to sink and now that its in the tank, it has this white fungus looking stuff oozing out of it. Is that of concern or will it go away with time? Thanks again.

[nacra99]

I call em "fart gasses". Really it's Hydrogen sulfide. (i made a typo earlier when i said SO2.. it's really H2S).
It smells like rotten eggs or farts after eating too many deviled eggs.
Don't want to bore you with more chemistry, everybody knows about the nitrogen cycle in the aquarium, not many people know that there is also a sulfer cycle within aquariums. It takes place in low oxygen locations like deep in your substrate.
Usually it's not an issue in the aquarium, but occasionally you can have enough build up such that when you mess with the substrate, bubbles of H2S gas bubble out. If you want to read about this in depth, a google search should bring up tons of articles.