What is this?

[Alec18]

So when I was changing my water I stuck the nozzle deep inthe gravel and a bunch of really dark stuff came up and it smelled bad. Is that the bacteria under the gravel. I've seen a bunch of material before but not this much and this dark. What could this be?

 

[Bubbles0oO]

Super concentrated poop.


Was it under a decoration?

 

[Fishfur]

DId it smell sort of swampy or like sulphur ? if so, you have anaerobic bacterial decomp going on under the gravel. Often you get gas bubbles coming up when you disturb the gravel if this is happening.

Whatever it is, needs to be well vacuumed, stirred up and filtered out. Carbon in the filter will take out the smell if it gets into the water.

I keep MTS snails.. Malyasian trumpet snails, because they burrow in the substrate and sort of churn it over a bit, which helps prevent this from happening. But if you overfeed, or don't vacuum now 'n then, you can get a lot of built up crud, especially under ornaments, rocks or wood.

 

[Alec18]

It's all over. Should u vaccum all of it out? It's fishy smelling

 

[Fishfur]

Fishy is better than swampy, for sure. Yes, vacuum it out, as much as you can. You can stir up the rest, and let the filter take it out, but then you'll have to rinse out the filter, it will clog up pretty quick with a load of stuff like that.

 

[Khuligirl93]

When is the last time you vacuumed your gravel? That shouldn't happen if you're siphoning regularly

 

[Alec18]

When is the last time you vacuumed your gravel? That shouldn't happen if you're siphoning regularly

Today. I don't go deep in the gravel. I just do the top because I was told not to because that's where the bacteria is

 

[DavidAl]

If it has a rotten egg smell, it is most likely hydrogen sulfide. You can prevent this by vacuuming regularly, which will also eliminate the massive detritus build up. How deep is your substrate?

David

 

[Fishfur]

The beneficial bacteria that filter your tank water do not live in the gravel.
This is a common misconception.

I will no doubt hear arguments on that. I don't deny there are likely some few of them living there, but the vast majority of BB colonies live in the filter media. Not the gravel, not the water, not the biofilm in the tank.

This is why you can take a mature filter off one tank, stick it on a brand new tank and have the new tank instantly cycled, because the BB are in the filter. Many keep bare bottom tanks, and if the BB lived mostly in gravel, those tanks would not work very well. But they work just fine with cycled filters.

BB require solid surfaces to attach themselves to, but they also need a constant food supply and they don't really get that on the tank bottom, because the filter draws the water out all the time, and removes the vast majority of the bacterial food supply as it does so.

The reason most filter media is made the way it's made is so it will provide maximum surface area in a small space, to allow for the greatest number of bacterial colonies to grow there, where food is always available from the water flowing by.

Gravel must be vacuumed regularly or this is what happens, and it can really play heck with the water parameters if you allow it build up too much.

 

[Alec18]

The beneficial bacteria that filter your tank water do not live in the gravel.
This is a common misconception.

I will no doubt hear arguments on that. I don't deny there are likely some few of them living there, but the vast majority of BB colonies live in the filter media. Not the gravel, not the water, not the biofilm in the tank.

This is why you can take a mature filter off one tank, stick it on a brand new tank and have the new tank instantly cycled, because the BB are in the filter. Many keep bare bottom tanks, and if the BB lived mostly in gravel, those tanks would not work very well. But they work just fine with cycled filters.

BB require solid surfaces to attach themselves to, but they also need a constant food supply and they don't really get that on the tank bottom, because the filter draws the water out all the time, and removes the vast majority of the bacterial food supply as it does so.

The reason most filter media is made the way it's made is so it will provide maximum surface area in a small space, to allow for the greatest number of bacterial colonies to grow there, where food is always available from the water flowing by.

Gravel must be vacuumed regularly or this is what happens, and it can really play heck with the water parameters if you allow it build up too much.

My filter after while has like green slime all over. I wiped a lot of this off. And rinsed of the filter cartridge and bio filter off in treated water, does this take away bacteria

 

[DavidAl]

A lot of it depends on how long the filter has been set up. A mature filter can handle all the elbow grease you want to give it. A newly set up filter, on the other hand, will most likely suffer some bacterial loss, which may or may not cause a blip in nitrification.

David

 

[Fishfur]

So long as you rinse in tank or treated water, the bacteria will be fine. Some will get knocked loose, but most will be untouched. They are pretty sticky. It's possible to disturb them if the filter is quite newly established, when the colonies are smaller and may not have penetrated as deeply into the media as they will later one.

The green slime is likely algae, and if it very soft and sort of blue green, quite dark, it may be cyanobacteria, aka blue green algae. Wiping it off does no harm, and won't bother the bacteria either.

Filters can grow algae if there is algae in the tank or they get enough light on the filter itself. My 30G tanks are in a south window, and those filters, Aqua Clear 70s, grow a nice film of green where the sun gets to them, so I covered them in foil to stop it. It worked pretty well.