Cycled tank...then nitrites popped up?

[Nem0]

I had my tank cycling for about 2 weeks- i used live sand, live rock, and biospira and phantom feeding. I took tests and got 0 ammonia, 0 nitrites, and about 40ppm nitrates. then did a water change, left it for a few days and did another test before adding fish - 0 ammonia, 0 nitrities, 10ppm nitrates.

Today, I did my normal tests and got 0 ammonia, .5ppm nitrite, 20ppm nitrates. I'll be doing a 20% water change, but I was curious why this may be happening? the increase in nitrites?

Thanks!

 

[Big G]

It's not uncommon to get false positive test indications for nitrites. On the other hand the hobby test kits we use are not completely accurate so your testing that showed O , O, 10 may have been off a bit. Usually takes 30 days or so for a tank to go through the complete initial cycle. And usually takes 14-21 days for the nitrite cycle to finish.

 

[Nem0]

It's not uncommon to get false positive test indications for nitrites. On the other hand the hobby test kits we use are not completely accurate so your testing that showed O , O, 10 may have been off a bit. Usually takes 30 days or so for a tank to go through the complete initial cycle. And usually takes 14-21 days for the nitrite cycle to finish.

okay got it, any suggestions to make sure my parameteres are correct?

 

[Big G]

What brand of test kit are you using? And have you checked the expiration date if one was provided?

 

[Nem0]

What brand of test kit are you using? And have you checked the expiration date if one was provided?

using the API test kit, and yes. it expires in like 2 years. I've used the API kit for a while with no problems on accuracy (to my knowledge)