Fishless Cycle - Progress So Far

[ice-nine]

Hi Fellow Aquarists, here's my aquarium saga so far.

My wife and I thought it would be a good idea to get an aquarium for my son for christmas. He's 18 months old and we figure he should get quite a lot of enjoyment out of it. We purchased a bundle package containing the filter, filter medium, heater, 16 gallon tank with cover and various conditioning chemicals (Hagen Nutrafin brand). At the time of purchase I also picked up a 22lb bag of "natural" type gravel. So back on the evening of Dec 28th, 2010 I setup the tank, filter and heater. While setting it up, I rinsed the gravel in the kitchen sink twice, strained it and then placed it in the aquarium. Immediately the water turned completely cloudy. I dosed with the dechlorinator and left it for the evening. In the morning, the water had cleared significantly, but was still fairly cloudy. I dosed the tank with 30ml of the Nutrafin Cycle as the aquarium's instructions directed. Instructions were to continue dosing with Cycle over the next few days and then to add fish. Here's where things start to get interesting.

So shortly after that first dose of the Nutrafin Cycle and waiting for things to run their course, I stumbled upon this forum and the Fishless cycle process. I ended up second guessing the approach I was taking (as directed by the instructions that came with the aquarium). A few days and lots of reading later, I was convinced that the Fishless cycle is what I should try to achieve.

To start over (phase 2 i call it - January 2nd,2011), I emptied the tank and gave the gravel multiple washes until the rinse water ran clear. The rinsing performed on initial setup was insufficient in my opinion. After the gravel was in place and the tank filled up I was happy with how clear the water was compared to the first time, what a difference. I did leave the filter, original water and medium contents contained within untouched when I installed it this second time. I brought the water temperature up to about 86 degrees F and dosed with Ammonia to about 4-5 ppm. Here's a log on what the chemical tests have shown since:

Date-------Ammonia------Nitrite---------Notes
02/01/11---4------------0
03/01/11---4------------0
04/01/11---6------------0.05
05/01/11---5------------0.2
06/01/11---4------------0.3
07/01/11---3------------0.6
08/01/11---2------------1.6
09/01/11---1.5----------3
10/01/11---1------------4.5
11/01/11---0.125--------12--------------Dosed 3ml Ammonia, brought level up to 1ppm
12/01/11---0------------12.8------------Dosed 3ml AM – Reading 0 by 17:00. Dosed 6ml PM
13/01/11---0------------16--------------Dosed 5ml
14/01/11---0------------16--------------Dosed 4ml
15/01/11---0------------20--------------Dosed 5ml
16/01/11---0------------20--------------Dosed 5ml
17/01/11---0------------30--------------Dosed 5ml
18/01/11---0------------30--------------Dosed 5ml
19/01/11---0------------36--------------Dosed 5ml


The nitrites have been off the chart recently so I've been diluting the water sample to about 1/20 volume to get a readable value. So far it looks like the Ammonia converting bacteria are doing their job most effectively as they consistently bring the ammonia level to 0 within 12 hours or less after addition. The nitrites however, I am starting to get a little worried that the concentration is getting a bit high and that they will never go down. How high will they go?

At this point, should I do a partial water change to bring the nitrite concentrations down, or wait it out. Should I cut back the dosage of ammonia so the nitrite converting bacteria, once they do make their tardy appearance, aren't overwhelmed with nitrite levels sky high.


ice-nine

 

[waterdrop]

Welcome to our freshwater beginners new tank section ice-nine,

Each 1ppm of ammonia is converted by the A-Bacs into about 2.7ppm of nitrite(NO2), so the N-Bacs are there, they just have a -lot- more material to convert!

You're doing fine. You're in the second phase, the "nitrite spike" stage and it is often a good deal longer than the first phase prior to getting nitrite. There's no need to water change yet as that will just shock the bacteria into a pause. It is important though to be checking your pH to make sure your buffer doesn't get used up, leading to a big pH drop and causing the processing to stop. At a pH of 6.2 the bacteria will stall and at 6.0 they'll stop for a long time.

Yes, though, we do lower the ammonia dose during the nitrite spike, to perhaps 2ppm instead of 4-5ppm. This helps to slow the overall amount of nitrogen in the system and let's you get closer to the end of the fishless cycle before having to change the nitrate out.

I would also lower your temp to 84F instead of 86F. And post up your tap water stats for the members also.

~~waterdrop~~

 

[ice-nine]

Did some watertests on my tapwater and came up with the following values:

Ammonia = 0, Nitrites = 0, Nitrates = 0, PH = 6.6

I tested the PH of the tank and it read about 7.6+. This is the maximum that my PH test kit reads. I tried diluting with 50% tapwater and came up with a reading of 7.2. Not sure if this would make my tank water around 7.8 because I think the PH scale may be logarithmic.

Each 5 ml dose brings the ammonia level up to about 1ppm, which is what I was lead to believe would be the optimum level for this size tank. Should I try for 2ppm? I figure the end result would be more bacteria for a higher bio load, with the downside of a longer cycle.

Thanks for the great info and encouragement that those nitrite to nitrate converting bacteria are actually there!!

ice-nine

 

[waterdrop]

No, you don't use dose to adjust colony size. It's decidedly weirder than that. There are potentially hundreds of different species of bacteria in the tank. Part of what you are using dose for is to select for the correct species (we are trying to grow two specific species of chemolithoautotrophs, Nitrosomonas spp. and Nitrospira spp.) Actually, that makes it sound worse than it is, our main concern is that at about 8ppm the wrong species can take over and really mess things up. But even more important than that, we are not trying to match our colonies to our bioload in fishless cycling but instead create really robust colonies so that when we do our initial fish introduction, these colonies will be much larger than needed and then "drop down" in size to be optimized to our bioload. If we try to make our fishless cycle faster by attempting a small bioload, small colonies game, we usually fail at the fishless cycle and end up with a surprise fish-in cycling situation on the tail end of our fishless attempt. We've seen this happen a fair number of times.

So, instead, you want to dose to correct concentration levels for the phase of the fishless cycle: Dose 4-5ppm during the initial early phase (this seems to get a more thorough mix throughout the complete tank circulation and get a better start going) and then drop the concentration to 2ppm or so for the "nitrite spike" stage of the fishless cycle. Once nitrite(NO2) is dropping to zero ppm within 24 hours after dosing, it's time to begin easing the dose back up toward 5ppm for the finish. You always want it to be about 5ppm by the end to encourage as robust a set of colonies as possible. If the fishless cycle gets in to a "sticking problem" at the very end, with traces of nitrite seeming to never go away when you do your 12-hour tests, -that- is the time that one can consider switching over to fish and cutting the fishless cycle short.

~~waterdrop~~

 

[ice-nine]

Date-------Ammonia------Nitrite---------Notes
20/01/11---0------------32--------------Dosed 5ml
21/01/11---0------------30--------------Dosed 5ml

It looks like the nitrites are dropping finally, though since I'm cutting the sample so much to get a readable level I figure my margin of error is +-5ppm at the very least. A friend of mine has some filter medium that I have the option of using. Too bad I didn't know about this when I started my cycle. Not sure if the addition of mature media would make much of a difference at this point.

 

[ice-nine]

Today a friend of mine made available filter media from a 44 gallon established tank, the media consisted of pretty much everything within his canister filter. After making the transfer, there's lots of gunky goodness in my tank now. The readings over the next week will be most interesting to watch as readings over the past couple of days the Nitrites have been reading 30-40ppm.

Cheers,
Ice-Nine

 

[ice-nine]

After adding filter media from the established tank I have seen a drastic reduction in nitrites. 36 hours after addition, nitrite levels are around 16ppm. I would, however, like to try removing the mature filter media shortly after nitrites reach zero and see if enough nitrite eating bacteria have actually established themselves in the tank and are not just hanging out on the mature media I recently added. I don't think my wife would like to have a couple slimy bags of charcoal and filter sponges as ornaments in the tank.