Nitrites

[Solarris]

This morning I took the Emperor 400 HoB filter off of my 55 gallon tank and swapped all the biomedia in it into a new canister filter that I've had running for 5 weeks on that same tank. After that I did a water change of about 40 percent. This evening I noticed my featherfin catfish was hanging out upside down at the top of the tank with his mouth at the top of the water. This is not like him, he usually hangs out under some driftwood at the bottom. I immediately tested the water. My ammonia is 0 and nitrates are 5ppm but my nitrites look to be right between .25 and .5 ppm on the color chart. I am going to do a water change right now but wondered if this could be because of the filter change and how worried I should be. I thought having the canister hooked up for 5 weeks before completely swapping over was long enough, especially since I swapped the biomedia from the old filter to the new one. Any advice would be greatly appreciated.

 

[PNWaquarist]

I would think so too. Is your tank heavily stocked? Did the media have a chance to dry out during the swapping?

In case you haven't done so already, add Prime now and prepared to do daily WCs until the nitrite subsides.

 

[Fishfur]

That should have been more than long enough, given you seeded the new filter too. Just keep changing water and testing, hopefully it's a very short lived issue.

 

[Solarris]

The only fish in there are my upside down cat, a small pleco, and 6 platys. My husband says that I didn't account for adding oxygen to the water after taking off the hob filter so we just added a couple airstones. How do you oxygenate the water with just a canister filter? I've never used a canister filter before.

 

[PNWaquarist]

I don't think that lack of oxygen is the problem, as long as there is a good inch or so of air space between the water level and the hood. Adding airstones will help re-establish your colony of nitrifying bacteria.

I think you'll be OK soon enough.

 

[Fishfur]

Oxygen gets into water mainly at the surface, or from growing plants during the day if the tank is planted.

There is a constant gas exchange going on at the water surface all the time unless there is no circulation at all. In that case, the water is stagnant, and because of the lack of circulation, no oxgen gets from the surface to the lower levels. This can't happen in a tank with a filter or air stone running.

Just fyi, cold water holds more oxygen than warm water, so if temps are high, or need to be high for a short time, say, to treat Ich, using an air stone helps increase oxygen levels a bit. Warm and cold are relative terms.. 70 F water holds more than 85F water does, or vice versa.

An airstone does not add oxygen directly, but it disturbs the water's surface, which increases surface area, which increases gas exchange and thus increases oxygen levels. For ordinary temperatures, it's not necessary, but many like the bubbles and that's fine.

Another way to disturb the surface is to allow the return water from any filter to fall into the water so it splashes some, often by lowering the water level a bit. Same effect as an airstone. The BB need oxygen but the water running past them in the filter brings plenty of it, whether it's a canister or HOB.

It's bit odd that your nitrites are up, but it should be short lived.

 

[Solarris]

It only took a couple minutes after adding the air stones for my catfish to move back down to his usual spot. I did the water change, about 50%, then tested nitrites again. They were at zero that time. Unfortunately I have lost one of my platys during this. The others all seem to be ok though.


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[Fishfur]

Sorry for the loss.. but it sounds like things are improving. Shows how fast gas exchange works though.

Good luck.

 

[Solarris]

I am thinking about adding a wave maker to my tank for airation. I have a 800gph wave maker but am afraid that's too powerful for platys and I want to add some guppies also. What size wave maker should I get?


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[Fishfur]

They are usually only used on salt water tanks and I know little about them other than that. I suspect plates and guppies would find it bit rough though.