I have a 46g bowfront that I just switched over from having 2 adult yellow labs, a Alt. compressicep, an unknown adult pseudotropheus, 2 clown loaches and a bushynose Pleco to having 4 Aust. rainbows, same pleco, same loaches, 2 cory's from my daughters 10g which we took down. I reduced the bio-load by doing this. It has a fluval 404 and all I did was clean the filter during this switch. Which it was about 2 weeks over due. I rinsed the media & sponges, refilled & returned to tank. No water change.....nothing. I added 5 plants (to see if my well water is okay for plants) and removed about one third of the rocks so it would be a little more open. (all of this yesterday) Today I test the water and my amonia is at 0, Nitrite 0.3, Nitrate 25. (usually it is around 15-20) I planned to do a water change today anyway as it is a week overdue. (started a new job and it's been hectic). I was surprised that I have a nitrite spike. All fish are accounted for , when moving rocks I didn't notice any buildup of gunk. I did disturb the sand more than usual while putting plants in, could this have caused a problem?
When I do water changes I have a stick that I poke & stir around the rocks while trying not to cause a rock slide. Now there are fewer rocks and more visible sand so this will be a bit easier. I actually have a heavy salt content right now as my loaches and a catfish have ich. I always use salt & heat to cure ich. I did introduce a catfish to the tank a couple of weeks ago, who is now in a different tank, even though he doesn't appear to have ich I am afraid maybe the water was the carrier.
You said you cleaned the filter during the change. Did you rinse it in tank water? If you used fresh water to clean it maybe you lost your biological filter (good bacteria). Just a thought I had I could be way off lol.
The only thing I did to the tank aside from adding plants, reducing number & size of fish was a regular filter cleaning. I rinse in tap well water like I have done since I set the tank up over a year ago. I add water conditioner/dechloronator even though I do not have Chlorine or any additive in the water. I do this just in case something unusual shows up in the water if that's possible. The Fluval is plenty big enough in the bio-load department as all trays are filled with a combo of bio-max rings and bio-balls. The bio-load of the tank has decreased so the bacteria column should have no problem handling what's in there. It must from releasing a bacteria pocket from the sand as cichlidaholic said. I may further reduce the amount of rocks to make it easier to stir up the sand. The fish seem fine so far and I am going to test again in the A.M to make sure there is no further spike. I guess I'll add another thing to my "lesson learned" column.
My "lesson learned" column gets longer every day... :wink:
Reading over your last post, it might be a combination of things. Rinsing your filter media in tap water rather than tank water, reducing the fish load/bioload, and stirring up the substrate may all contribute to the changes.
Hi, yeah it's back at zero this morning. I thought that rinsing from my tap would be fine as I have no Chlorine, salt or anything other than water straight from the ground. No filters or softeners between the well and my tap. That was the quickest nitrite spike I have ever experienced, I almost wonder if maybe I had something on my hands like soap or lotion.......I don't think so but it is possible.