Ever had a cycling like this?

[Numi13]

I set up a 75 reef with 40 lb of live sand, Marco rocks and a 20 long sump/fuge. The only thing in the sump right now is a skimmer and return pump. It ran for about a week and I decided to throw in a raw shrimp. The shrimp has been in for 4 days and NH has never gone above 0. The NO2 has climbed to 1.0 and the NO3 has never been above 0. I wonder if the week with just live sand produced enough nitrosomonas etc. bacteria to be able to keep up with oxidizing the NH and the nitrobacters etc. haven't caught up with NO2 yet. Any thoughts? The shrimp is fuzzy now.

 

[Boomer]

The shrimp is fuzzy as it has marine fungus growing on it. More than likely the live sand sand has kept up to any Ammoina and converted it to Nitrite and the Nitrate has not caught up. You are looking for the Nitrite to be 0 ppm.

 

[Numi13]

Thanks Boomer. I know the shrimp is fuzzy from fungus, I was just trying to show what stage of decay is has reached. I know my parms need to be 0. This is not my first tank. It is however, the first tank where NH started at 0 and has never risen but the NO2 has and I've used live sand before. I agree with you're assessment. I guess I'm just looking for validation of the idea.Have you ever seen a cycle like that before? Now I'm just waitin' on the NO3.

 

[Boomer]

Num, 2 things could be going on here or a combination.


1. Nitrite inhabits the growth of Nitrare producing bacteria. So, their population density is low and can not keep up yet.
2. It has live sand and the Nitrate that is getting produced is going through Facultative Denitrification,where the Nitrare is getting converted to Nitrogen gas, which exits the tank. Thus, you see no NO3.

More than likely # 1

 

[Numi13]

Interesting Boomer. So the very compound that the bacteria oxidize also inhibits their growth? I'd like to see the equations on that. I'll have to do some research. And the facultative denitrification, would that indicate low oxygen since it is an anaerobic process?

 

[Boomer]

Yes, higher NO2, produced by those bacteria that covert Ammonia to Nitrite inhabits the growth of bacteria that convert Nirtite to Nitrate. I have a book on it so where. High Ammonia does the same thing.

Look for ^Anthonisen et al. (1976) or Seawater Aquariums by Spotte, page 125


Yes, low O2 in the SB. The reasons behind LR and SB is to try and produce Facultative Denitrification Bacteria, where they convert Nitrate to N2 gas, which can give very low and at times zero Nitrate. Facultative means can do with or without.

In Facultative bacteria, it means those that can live in zero O2 or low O2 but prefer low O2. If there is zero O2, full anaerobic, there is no conversion to N2 gas and you get the production of Hydrogen Sulfide....a no-no in a reef / fish tank.....= DEAD. There are different types of Denitrification.

Facultative = some O2 or just anaerobic
Obligated Anaerobic = must be zero O2
Obligated Aerobic = must have O2

 

[Numi13]

Parms the same