Why do I suddenly have Nitrites??

[mound]

OK - over the past 21 days, I spent the first 14 days doing a fishless cycle on a 125g tank.. It got the point after 14 days where I could put 5ppm NH3 into the tank, and 8 hours later, it would all be gone, and N02 would all be gone. N03 would of course continue to build up...

Since I don't get my fish delivery until today, I continued "feeding" with NH3 to keep the bacteria alive until I was ready to populate the tank.. Kept testing, NH3 and N02 would go back to zero..

Ok - last night comes along, night before my fish order arrives. I do a 50% water change.. Dechlor the new water, add salts/baking soda to get the water paramaters right..

Do test - NH3 of course was at zero, Nitrates are 20ppm, and here's what's bothering me, Nitrites are reading ~0.3ppm.. (if I let the test tube sit for several minutes longer they the kit says, the color eventually turns to the 0ppm.. but having used this test on other established tanks, it shouldn't give a reading and then change to a zero reading if in fact it's zero right?)

Anybody have any idea what's going on here?? Again - there are still no fish in the tank - but they arrive this afternoon..

Thanks

 

[loganj]

I suspect the water change had something to do with it. .3 isn't all that high and it'll probably be either gone or down to just a trace by the time your fish get there. JMHO

 

[mound]

I suspect you're right.. it's just odd.. my tap has no nitrites..

 

[mound]

do you think I should do another water change /re-add salts etc.. before putting the fish in there to further reduce the nitrAtes? I normally would change water in a tank that had Nitrates of 20ppm, I'm a little disconcerted that my 60% change diluted it to 20ppm..

 

[loganj]

I don't think nitrates of 20ppm will be a problem for the fish. I'd add the fish, let them get comfortable, and then think about doing some water changes. The slower you change the water parameters, the better. Let the bacterial colony get adjusted to the bio load. I've gone to peoples houses to check their tanks before and seen nitrates so far off the charts that they were still unreadable after diluting the water sample 50% with distilled water! Fish were doing OK in there...but so was the algae. JMHO.

 

[mound]

yeah, I'm not too concerned about the Nitrates, I'm more curious as to if in fact I have Nitrites, because the test isn't giving me the same results I'm used to seeing on my established tank (that is, it reads 0ppm after 5-8 minutes, but until that time, it reads .3 - .5ppm, whereas normally when nitrites are actually 0ppm, the reading never changes color during the wait time..)

 

[nugrad2005]

In my test kit you have to let the test stand for 15-20 minutes before reading it. Are you sure you're reading all the directions that came with your test kit? There are chemical reactions going on in the test tube that is why the colors are changing, they don't indicate anything until you wait the designated time.

-Dan

 

[mound]

yes I'm sure.. I've been doing this same test for years.. you drop in 5 drops and wait 5 minutes.. normally the water is immediately blue and stays blue. with the new tank, it starts purple and changes blue.. quite strange..

 

[nugrad2005]

Same brand test kit you've always used? I suppose some could be different? Just a thought.

-Dan

 

[mound]

yeah, it's the same test kit - same bottle of nitrite solution - side by side testing both tanks at the same time with the same test kit - one tank it turns purple and slowly to blue, the other (the established tank) starts and stays at blue..

 

[nugrad2005]

Hmm...interesting...yeah i'm of no use to you whatsoever.

-Dan

 

[mound]

8)