"bad eggs"

[gadazobe]

I've just cleaned out my community tank after smelling "bad eggs" in it     I got rid of all the rotting plant pot "sponge" that caused the smell :grumpy:   but I noticed that the surrounding gravel has gone black  :what:   I've taken out as much as I could and there's no more smells.  Can I keep the rest of the blackened gravel or does it all have to be changed?   This is a heavily stocked, well planted 45 g community tank.  All water parameters are good - even before I cleaned and the fishies seem to be fine.  What now - leave the black gravel alone or change it?

 

[Tatya]

What does the black look like? Is it black that can be sucked up like a powder (I guess not)? Is it a coating on the gravel? How much (as a percentage of the surface gravel) of the gravel is black? If its just 5% or so of the gravel surface which could contain bacteria then removing it shouldn't cause much problem - if its +80% then you'd get a mini-cycle.

Have you already removed some of the gravel how much?

If you've already removed a lot then I'd be tempted to wait a few days before removing the rest - keeping a close eye on the water quality incase you get a mini cycle.

 

[gadazobe]

There was some powder that I sucked up, but some of the gravel seems to have petrified - it's not a coating on it, the whole pepple has turned black. There's about 15% of the tank like that. I took out as much as I could, but I didn't take it all, as you said, I didn't want to start a new cycle.

 

[Tatya]

How easy would it be to remove the rest?

I'd wait a day or two and if you are still ammonia and nitrite free then remove the rest.

I'd like to know what caused it though. I guess its most likely something to do with the rotting sponge. But hopefully one of the others will have more ideas.

 

[Tatya]

Just a thought - Is there a chance that it could be a type of algae?

 

[gadazobe]

Is there an algae than can petrify stone?

 

[Tatya]

Not that I can think of  

It was just that all I can find about gravel turning back is black algae. So I wanted to check. It would almost have made sense too - more nutrients around the pot hence black algae. Alright it was a long shot!

Sand will turn black when it doesn't get enough oxygen down through it. I've never seen that though so I don't know if it looks petrified or not. Did you notice any bubbles within the black gravel you disturbed? That could indicate oxygenless dead spots.

 

[Great Lakes]

Gad, do you have an undergravel filter? If so I would leave it for a bit, if not, you will most likely have to remove the black stuff to clean it.

 

[gadazobe]

I haven't got an underground filter and there were a few bubbles when I disturbed the gravel. I've cleaned as much as I can and turned the gravel over - so that what was on the bottom is now, hopefully, on the top. It hasn't happened anywhere else, just in this one front area. :cry:

 

[Great Lakes]

Unless it is unsightly, I would leave it. It seems you are on the recovey path, and it will take care of itself

 

[Rose]

Brown algae will do that when there's a large amount of it.  Green algae will do it too. Trying to remember which one is the more common to do it. Rose

 

[gadazobe]

Went to my LFS yesterday and he told me that my problems with "dead spots" would be solved with an underground filter as well as the other filter, so he sold me one. Is he right ?It can't be bad with another filter, but how do I put it in without stripping down the tank. I've got about 25 various fish in it and I don't want to start another cycle if I strip it down. Anyway, where do I put the fish while I'm doing it? :what: :what: I'm confused

 

[Rose]

One way to get rid of bad spots is to do a good gravel cleaning. Don't put a UGF in your tank. It'll destroy the plant roots. You'll have to take it out ever year to clean under it. It's more hassle than it's worth. R 8)

 

[Dragonslair]

You don't need to put an undergravel filter down to get rid of dead spots. The cheaper and easier solution is to add a small powerhead to the opposite side of the current filter. So the water is pushed in both directions. Decomposition of organic materials will have the same effect as you have described. I have an internal Juwel filter that works with a powerhead, and I have put a small one opposite at a lower level. About 4" above the gravel and this is suffucuent to stir the water around the tank without disturbing all the waste and plant root system. The fishes too can choose which levels they wish to swim at depending on their individual abilities.

 

[Dragonslair]

Sorry, my spelling is atrocious-I meant to spell SUFFICIENT. :laugh: :laugh: