Toxic sand bed?

[6stokes]

I have a 2"-3" sand bed. My tank has been up for about two years and in exceptional shape. All parameters are perfect including a balance between CAL/ALK/PH. I have great growth with all soft coral etc. My problem is the last two times I did a partial water change a fish died within two hours. These fish were the epitimy of health and never showed any signs of stress or sickness. The only thing I can figure is when slightly stiring the sand I get a greenish cloud and maybe that was toxic.
Any ideas folks?

 

[teen]

can you post water parameters?
i think if you did stir somthing up, it would leech into the whole tank so you would probably see some high nitrates.

 

[6stokes]

Nitrates are 5. Take my word for it, the water is perfect.

 

[maxalmon]

What part of vegas are you in, I'm over in the NW. harrybarkers@aol.com, always looking for other reefers to trade with..
.
I've read about a type of gas buildup in deeper sandbeds due to an increased growth of bacteria.
(this was from a google search)
This rapid bacterial growth rate causes the release of nitrogen gas which becomes visible as bubbles in the sediments.
Rapid bacterial growth rates only occur without competition for space or nutrients. As the bacterial populations fill in all the open spaces growth slows and may stop altogether. Some bacteria also secrete a exterior covering called a glycocalyx. These are made of a hard sugar-like material similar in consistency to rock candy. Rapid bacterial growth may produce so enough of this material to glue sediments together. These sediment lumps may be glued so tightly together that hammering is needed to break them apart.
Lump formation is a disaster for the biological filter. The lumps restrict water flow and trap organic material where it can rot. Additionally, lump formation shuts down the biological filter by covering the bacteria and preventing them from metabolizing nutrients. This, in turn, causes the tank nutrient levels to skyrocket.
hope this might help

 

[6stokes]

Good information. Sorry about my profile saying Las Vegas, I now live in Carson City. I'll change it right now.
Does anyone know if I can correct the sand condition, or do I need to start over?

 

[rujelus22]

Sorry to hijack but where do you go for fish in Carson City, I live in reno and theres only one saltwater store here and I really don't like it

 

[joesalmi]

Sounds to me like it's just bacteria and algae that is in the sand. Over the years the waste in your tank has settled and mixed with the sand. Yes this is toxic and I would pay very close attention to your fish etc.
What you might think about doing is cleaning the sand bed out some. If you can wait for the green cloud to setting back down and transfer some water to another tank or if you have another tank ready, this is the time to grab all that live and move them. Stir up sand back up and let the mess grow, and then let the filter do the work. Make sure that you clean the filter cartridges before and after to ensure that you are cleaning the system and not polluting it again.

 

[maxalmon]

Just a thought, and I have no idea if it will work or if it's a good idea, so those who are more experienced with this type of situation, please chime in. Should he start replacing the sand? maybe vaccume out a small area into a bucket of tank water, rinse it very well and then replace the cleaned sand back into the tank or should he simply replace the sand with new LS. Possibly the type sold wet, in a bag with bacteria... Or would it be best to take the LR and everything else out and place into a QT and start over. Sorry for kinda taking over asking questions for you, but I had a problem like this a while back...

 

[6stokes]

Originally Posted by rujelus22
Sorry to hijack but where do you go for fish in Carson City, I live in reno and theres only one saltwater store here and I really don't like it
It's the same in Carson. I have to order everything online.

 

[6stokes]

Let me state a couple of other things. I do not have filtration other than the live rock and live sand. I do however have fluidized bed filters, which I swear by. Also, I think I may have caused the problem of killing the two fish by stiring the sand too deeply. Is that possible? The cloud I was talking about disappears very quickly and it desn't change the water parameters. I think each fish may have breathed, for lack of a better term, the cloud and it was just too much.
I have plenty of circulation as well, about 20 turns an hour.
Maybe I just need to be more careful and not stir up the sand? :thinking:

 

[joesalmi]

Well that could be the problem right there. your sand is filthy. pull it all out and clean it. put in new container and let it settle before putting it back in the tank

 

[6stokes]

Ya, it was wierd. Both times it happened a very healthy fish was dead in about three hours. Don't you think by cleaning the sand I'll lose all my good critters and ecology?