Kessil

help? Nitrates are dissapearing while im cycling

Hi all

Please do not flame me. I am having an issue with cycling my tank I just got. It is a 75 gallon bowfront with a sump that holds about 15 gals. So 90 total.

When I started 2 weeks ago, I added live sand , some dry rock and some live rock (about 20lbs). Total lbs of rock is about 50. I bought. I also added live bacteria and dirty filter media from my other tank into the middle area of the sump. I also bought those bio ball thingys from Neptune- (5) that have live bacteria on them.

I have been doing a fishless cycle with ammonia and have never had an issue before. (I used this same method to cycle my IM 50 in 2 weeks or so.)

Only this time, my cycle will show its started- ammonia about 2ppm, nitrite the next day about the same, and then down to 0, and finally Nitrates around 20ppm.

Ive been adding ammonia daily about 1-2ppm.

Yesterday, I tested nitrates and it was around 80, so I figured time for a water change and ill be good to go. Amm 0, Nitrite 0

I did not add any more ammonia at this point.

Today, Im ready to do a good size water change, and just to make sure, I re-tested my nitrates- they are down to 0.

what the heck is happening!? Ive tested twice to make sure...0 both times. 0 amm, 0 Nitire too.
what the hell!?

I am running my skimmer during cycling so not sure if that is having any impact?

I noticed this pattern early on in the cycle too but dismissed it... when I first starting showing Nitrates, they disappeared after a day also. I thought it was just too early in the cycle to make any notice of it.

Now, its happening again after this many days.

Stats are:
Temp 78
Sal 1.023 (little low from what I started)
PH 8.1

Has this happened to anyone? Ive read online and it seems that it does happen... Nitrates dissapearing.
Is this a stalled cycle?
IVe added more ammonia today- just a little to see if I get a Nitrate reading tomorrow...
Ive been cycling over 2 weeks

Thoughts?
 
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If you add ammonia and the ammonia and nitrite get to 0 it isn’t a stalled cycle, it is fine.

I’m not sure where your nitrate is going, but likely consumed by a biologic process like bacteria. Normally nitrate accumulates in fishless cycles because we artificially add unbalanced nitrogen without phosphate or carbon so it can’t be used up biologically. Maybe you have those sources from your rock or something, which is fine.

Doesn’t seem like a problem to me.
 
Couple possibilities that I can think of. First bad test kit. This is the easiest to rule out by testing a friend’s tank or taking your sample to a lfs. Second thought is with your skimmer. Are you actually letting it bubble over into the cup and removing the skimate? If so then you’re removing nitrates. I think it’s unlikely that it would bring it down from 80 to 0 overnight though. The last thought is the bio balls. If they are like the marine pure ones then they can convert the nitrate into nitrogen which simply off gasses out of the tank. Again, 80 to 0 overnight makes this suspect but that’s all I’ve got for you.
 
Thanks so much everyone. The skimmer is not collecting skimate but it is bubbling... just some bubbles in the cup but not running over and clean bubbles.
Ive just tested again... and there are nitrates again... ammonia and nitrate are about 2ppm. Nitrates are high- possibly over 80 again.
Either I did not test right for the nitrates or something weird is happening. Like they hide and then come out in force at the first sign of ammonia.
At this point im going to do a water change anyhow...

My question is- my tank is at 78. and I have just 2 heaters...
can I just fill a few 5 gallon buckets and add to the tank as my garage is about 70F usually during the day or a little higher? Will that temp difference kill the Beneficial bacteria?

Bruce- you interested in the flame wrasses? lol
 
YES! ( to the wrasse question)

Also the marine pure balls aren’t converting nitrates. The nitrifying bacteria needed to convert nitrates (instead of Nitrites) need an anoxic environment. The 4” brick is deep enough, but not the balls.
 
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I would vote for testing methodology too.
There may be not be a set optimal temp for denitrification but studies have noted increased conversion rates as temperatures increase. Most of my reading of fishless cycles suggest temps 80-85 range to speed the process.
So one could suggest that taking 70degree-temp bucket-cycled bacteria and warming them up would improve their denitrifying efficacy.
 
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