Hey i have had my tank set up for 2 to 3 months now. All of my levels have been great. Right now all I have is a marble cat shark. I have been trying to find his favorite food (silver sides) and have been trying squid and shrimp. He did not eat the squid or shrimp so I only left the food in for 12 hours and took it out. I guess I left the food in too long because it raised my nitrite level to 0.25. I of course want that level to go down completely, so what is the best way to get that level to go down? I would prefer to not add any chemicals. Would water changes do the trick? I am going to wait a while to try the other kinds of food again. It is a 125 gallon tank, 79-80 degrees,=.

a little food spikeing your nitrite is a little disconserting to me in a 125 gallon system........water changes will help, i never do more than 10% changes at a time and no more than 2 per week {but thats me} - - from your picture I would definately look into some live material - -ie live rock - -i have a 20 gallon long system and we dropped a pretty large silver side in there to see what my large hermit would do with it - - -{2-3 inches} and he ate on that thing for 2 days with no parameter changes at all - -so i would do a little more research on your system ...you shouldn't be spiking anything with food in such a large system unless your throwing 1/2 a pound of stuff in there 2-3 times a day....you know???

Boss