Hi guys,

My tank has been running for about 2 months now, and I have the following fish:

Week 4:
3 Regal damsels
2 Clownfish
Week 6:
1 Red Sea Sailfin Tang
1 Black & White Bannerfish
2 Sleeper Blue Dot Gobies
1 Hermit crab
Week 7:
1 Yellow Tang
1 Neon damsel
1 Threadfin Butterflyfish
1 Porcupine Puffer fish

I have a 200 litre (53 US Gallons) tank. Salt levels are fine, but nitrite is between 0.2 and 0.5 ppm.

Is this a VERY high level of nitrite for the aquarium?

I've been doing 20-50% water changes daily for the last week, but no help at all. Im running an external Fluval 305 filter (biological only) as well as an internal Fluval U4 filter (mechanical only). I've fed my fish lightly once or twice a day for the last couple of weeks since I noticed nitrites were getting high! I have 25lbs of live rock in there as well.

How can I change this!

The nitrite levels you are seeing are at dangerous levels. Does the water appear cloudy? If so, the tank is probably in the middle of cycling and is experiencing a bacterial bloom. In that case I would change at least 50% of the water everyday until the nitrites drop to about 0.5 ppm, being very careful to not overfeed.

You might have to keep doing this for a couple weeks with a large tank.

My nitrite levels are 0.2 to 0.5 ppm, so they can't drop to 0.5 as you said. I think u misread my first post

Oops yeah for some reason I read 2 to 5 ppm. You are fine then

Thanks for the reply! So I should be ok? Do I still need to do daily water changes or can I go back to just the 10% weekly ones?

I think you have too many fish. They were added pretty quickly which could explain the nitrites and that may go down on it's own but in the long term I think the fish will way outgrow your tank. If I have the right fish the puffer gets huge, he needs some thing like a 90 gallon tank to his self and may snack on your other fish. Common names are tricky though so maybe I've got the wrong fish.

try not adding food for a few days. nitrItes should drop to 0 very rapidily.

meanwhile .2-.5ppm is not really all that high anyway.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

First of all I tend to agree with bob but I think you need to look at nitrates as well. Although not as toxic as ammonia or nitrite, they can cause serious problems if not kept in check. I think that chances are that yours are out of range (or may become so soon). I'd recommend at least 30 more lbs of live rock to increase your biological filtration and discontinue using the Fluval because of probable significant nitrate production. Bob can tell you about the benefits of macro algae and I'll agree with him completely.

I know that you don't want to hear it but your fish load is much too high. You have more in your 50 gallon than I do in my 200 gallon. I'd recommend re-homing the Red Sea Sailfin Tang (it will get too big and is in the same family as the yellow tang), the Black & White Bannerfish (generally doesn't do well long term), the Threadfin Butterflyfish (and any other butterflyfish in a tank your size), and the Porcupine Puffer fish (generally a bully and a tremendous waste producer).

Most folks will tell you that your tank is too small for any tang. I wouldn't disagree with them.

Good luck!

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Doc

Dr Hank's 200 gallon Reef Tank
http://www.aquariumforum.com/f46/drhanks-tank-3440.html

I took all the big fish back and looks like nitrites are good again.thanks for the help guys

Glad things have worked out.