Substrate Question

[I'm Your Huckleberry]

Hello! I'm a newbie to these forums and need some advice. I have a 135 reef tank that has been set up for about 2 1/2 years. It has an aragonite substrate that is about an inch to inch and a quarter thick. I have an pretty heavy fish bioload in the tank. Because of this I do weekly water changes of 20 gallons. Each week when I do the water changes I notice there are brownish gas bubbles in the substrate along the sides of the tank. I'm assuming they are throughout the substrate, but I can only see them along the edges. I always stir up the substrate to get the detrius floating so it can be sucked into the overflow box.

My question is...Should I be stirring the substrate up and releasing these gas pockets? Or, are these pockets something that needs to stay in the substrate to help with the bio process?

Thanks in advance for the help. Oh, and very cool site with tons of info. This should give me plenty of reading materila when bored at work on graveyard shift!!!

 

[Anonymous]

I'd recommend not sturring the substrate. This disrupts any anaerobic bacteria in the sand bed and the population has to start over. It also damages the little tunnels your sand bed critters have built.

If you don't like the bubbles on the edge of the glass it's perfectly safe to run a credit card along the glass to get rid of them.

 

[fyrefysh]

Sounds like you are using tap water or water with silicates, etc. in it. When I used tap water I always had a diatome algae bloom. Try some RO water, I think that you'll see less brown algae. HTH.

 

[I'm Your Huckleberry]

Fryefysh,

I use only RO for topoff, and have tested it to make sure it is free of silicates, or phosphates. I do not have any brown algae blooms, just brown gas bubbles under the substarte. I guess I'll try to not stir the pot and see what comes of it. I'd hate to make my critters work harder by having to rebuild their network of tunnels.

Thanks for the info!

 

[fyrefysh]

Sorry, just a thought. Maybe they are nitrogen bubbles!

 

[The_Big_Fish]

Gaseous exhange in your system is invisible ( as in clear bubbles).
In this case it is only visible due to the bubbles rising up through some diatomes I assume.

 

[Anonymous]

Bubbles in your sand is a very very good thing. It's nitrogen gas created by anaerobic bacteris converting nitrate directly to gas that bubbles to the surface and leaves your tank.

Enough of that, and you don't have to change water to get rid of nitrates.


Don't stir the sand. Anaerobic bacteria is good for the above reasons, but pockets of bad anaerobic bacteria can form. Areas of "black sand" contain sulfer and other poisons. Fine, as long as it stays under the sand, but if you stir that stuff up, you could poison your tank.

In moving a tank, it is best to remove all life and all the rock before fully disturbing the sand bed. I found a big patch of black sand moving a tank and thankfully there was nothing in the last few inches of water to be poisoned by it. It smelled like hell. If I had stirred that up when there were fish and corals in the tank, it might have killed some of them.