Designing an experiment: WC's during the cycle

[seabass]

While it's not uncommon for people to perform partial water changes while a tank's nitrogen cycle is becoming established, many people feel that reducing the total amount of ammonia in the water will extend the cycle. Therefore, Psychosis and I will be performing an experiment which tests this idea.

 

The 'Soft Cycle'

 

Question:

Does lessening the total amount of available ammonia, by performing water changes, significantly affect the time that it takes to establish the nitrogen cycle in marine aquaria?

 

Hypothesis:

Proponents of the soft cycle assert that if partial water changes are performed while an aquarium is establishing its nitrogen cycle, then only a portion of the excess ammonia is reduced, leaving enough to support the nitrifying bacteria and its reproduction to the carrying capacity of the system.

This experiment focuses on the results of nitrification and does not directly measure bacteria populations. As aquarists, we are more concerned with toxic ammonia and the time that it takes to establish the cycle, than with bacteria populations which will naturally fluctuate to match the carrying capacity.

 

Materials:

• two 5 gallon buckets

• two

Maxi-Jet 400

powerheads (with

Sure Grip

magnetic holders)

• one 40lb bag of

CaribSea Ocean Direct

live sand

•

Instant Ocean

salt mix

• Walmart distilled water

•

Seachem MultiTest Ammonia

test kit

• two uncooked raw shrimp (chopped)

•

Ocean Nutrition

food pellets

 

Procedure:

• add 20lbs of CaribSea live sand to two identical 5 gallon buckets

• fill the buckets with saltwater mixed to a specific gravity of 1.025

• add a Maxi-Jet powerhead set to run non-stop, for flow, aeration, and added heat

• add a chopped, uncooked shrimp to each bucket, to support ammonification

• test and chart ammonia levels in both buckets every day

• top off both buckets with distilled water daily

• add food pellets to each bucket each day, for additional ammonia production

• perform one gallon water changes on the test bucket (but not the control bucket), every other day

 

 

 

 

This test will be performed independently by seabass and Psychosis. The final materials for both testers have yet to be determined; however, the main difference should be the amount of food used. We are welcoming ideas, suggestions, and even participation in the experiment (possibly with some variation like: using LR instead of uncooked shrimp, adding Cycle bacteria to each, performing larger water changes, etc).

 

So what do you think? Is this a worthwhile experiment? Should we change our method? Do you want to participate?

[Jacobnano]

I don't know if gas exchange has an effect on cycling, as in having a lid on or off the bucket. Also topping off with the same water (make sure both are using pure RO water). Also does the amount of lighting affect the cycle? What is the temp going to be for each one? Just a few thoughts, can't wait to see the results.

[lakshwadeep]

Perhaps adding a more direct ammonia source would help avoid waiting for the shrimp to decompose. Testing for nitrites and nitrates could be a plus.

 

One thing I'm confused about is that the question involves the "establishment of the nitrogen cycle", whereas the soft cycle method (as I interpret it) is aimed at "softening" the cycle by limiting spikes and possibly shortening the entire cycle itself. I don't think that the soft cycle method is meant to be done independently of live rock.

[Jacobnano]

I like to help lol Anytime. I will come up with more ideas lol

[MikeTR]

are you not testing for nitrites? I'd bet in 30 days.. the bucket you haven't changed the water in will be cycled. The bucket you changed water in every other day will still have ammonia and high nitrites. In essence you'll prevent the cycle from even completing by changing the water. Will be cool to see the results. I've already done what you are doing though.

[djprofd]

wouldn't a heater set to the same specified temp in each bucket help to keep the test more consistent/lessen the amount of variables?

 

d.

[MikeTR]

I would do without the heaters..it would be hard to keep both buckets at the same temps.. however, if both buckets are sitting next to each other unheated, they'll be exactly the same temp.

[SpankythePyro]

add 2 heaters :-p give the water the temp we would normally maintain in a reef tank.

 

edit: looking over the above, i still beleive in using heaters, certain bacteria have sweet spots.

[Elite Twit]

Instead of live rock, what about using dry/base rock? If they are from the same place, at about the same weight bacteria would have more places to be able to colonize, showing if the lessened ammonia would have a beneficial/detrimental effect to growth as opposed to just letting things be. Live rock would definitely have too many variables in the way of certain organisms that may or may not be identical on each piece. While sand is great, all tanks need rock for the biological filtration. However, there are bare bottom tanks that do just as well as those with sand.

[Mr. Fosi]

Will you replicate these treatments?

[danimal1211]

Definitely following this one. I for one think soft cycle is the way to go. Is there anyway to control the temp in the room they're in to at least keep it near normal tank temps? It will be interesting to see if the diatom bloom will be noticeably reduced by the soft cycle.

[ajmckay]

add 2 heaters :-p give the water the temp we would normally maintain in a reef tank.

 

edit: looking over the above, i still beleive in using heaters, certain bacteria have sweet spots.

 

Why is everyone so concerned with temps? There will be slight temperature variation. Plus, we're only talking maybe 3-4 gallons of water... The pump alone will maintain a constant temperature above room temperature. In my water mixing bucket I don't use a heater because my quiet one 1200 heats the water up to exactly 80 degrees (since my basement maintains a relatively stable temperature)...

 

Testing bacteria growth rates in higher/lower temperatures will have to be a different experiment, it's only important that these 2 buckets be the same temp imo...

 

I'm also really excited to see how this turns out... I would love to participate but I don't have access/funds for the necessary equipment just yet.

[Mr. Fosi]

That's why Psychosis and I are both running the test. It would help if we could get a few others to run it too.

 

Having multiple people run it is better than running it once and declaring a result, however... One could argue that it is very bad practice to have several people all do it because they will all do it differently.

 

To be positive though, I don't think that having multiple people do it will compromise the results.

[lakshwadeep]

Interesting if nothing else.

The only reason I say this is that monitoring nitrite/nitrate levels will help to show if there are additional benefits to water changes or if these levels will be less affected (mainly nitrate is what I'm thinking about).

 

I think of the soft cycle as softening the ammonia level while not affecting the cycle time. I will be very surprised if the bucket that gets water changes has a shorter cycle. If we are lucky, we will show that lowering the ammonia levels will not extend the cycle.

 

The sand, shrimp, and food pellets will simulate LR. I know it isn't perfect. It would be nice if someone decides to perform the test with us, using LR.

 

After a while of thinking, I can see how even just measuring ammonia can be a good indicator of what is happening throughout the cycle.

[SpankythePyro]

its just much easier to replicte the environment you are trying to test

[MikeTR]

I think everyone is right; nitrite and nitrate tests are a good idea.

 

I think that it's worth repeating. I wonder if we'll see the same results?

 

I agree. I'm sure we can all learn something here.

[Psychosis]

Variations between our tests buckets is a chief concern, which is why we're trying to replicate them exactly down to brand names. No matter what we do, I'm sure there are going to be a difference in temperature or something, which is actually why I'd like to see more people testing. The greater amount of data, the less likely some fluke occured during the test.

[Project7Studios]

If you plan to add further amounts of food to consistently add to the amount of "new" ammonia, use pellet foods.

 

They are generally the same size and it should be easy to administer to the bucket.

[seabass]

Thanks for the thoughts everyone! I have decided to consolidate my responses to condense this thread. I hope that this doesn't create confusion, but instead, makes it more readable.

 

There are a lot of variables. I think the key is to have our test and control tanks the same. In order to accomplish this, I have proposed that we:

• use measured amounts of sand versus dry rock or LR as the bio-filter

(which should provide similar surface area and distribution of any organic material)

• not use a heater

(while test to test variations will occur, our test and control tanks will remain similar)

• use measured amounts of food

(one shrimp in the beginning, with food pellets added daily)

• not supplement lighting

(ambient lighting will be sufficient and will simulate common cycling conditions)

 

We considered using ammonium hydroxide as an ammonia source. Although this should be a valid test, I believe that the ammonification of the shrimp (replicating dead organic material found on LR) and the daily addition of food pellets (replicating waste from the living material on LR) will naturally simulate the cycling of typical live rock.

 

Our goal is to test to see if water changes can reduce the level of toxic ammonia in the water while bacteria populations are becoming established. While I don't believe that this will shorten the cycle, we hope to find that reduced ammonia levels are enough to establish the cycle in a similar amount of time (and that excess ammonia doesn't aid in the cycle process).

 

In addition to ammonia, I will also test nitrite and nitrate levels. I feel that this information will provide additional insight into the process.

 

I'm glad that a number of people are following along and we welcome more people to perform the test with us. We appreciate all the ideas; keep them coming!

[Urchinhead]

If you are serious about this I would be happy to help you put together a DOE doc for this that people can work from...

 

DOE being Design Of Experiment:

http://www.itl.nist.gov/div898/handbook/pri/pri.htm

[Urchinhead]

Got it. I suggest that because it means that we can actually publish something at the end of it that has a generally accepted methodology, a way to ensure consistency, as well as a way for it to be replicated by others for independent confirmation.

 

Side note... I was going to ping Fosi about collaboration on a DOE based 4 variable Bryopsis experiment... Mr. F...?

[Mr. Fosi]

Devil's in the details.

 

Rather than drop them here, PM me.

[Urchinhead]

Heheh. Yep. Planned to but knew you were monitoring the thread.

[seabass]

I suggest that because it means that we can actually publish something at the end of it that has a generally accepted methodology, a way to ensure consistency, as well as a way for it to be replicated by others for independent confirmation.

If practical, Psychosis and I are both interested. What would be involved?

[wombat]

1) Why are you using live sand and not sterile? This will be an uncontrolled variable that confounds any results you get.

 

2) "One shrimp" hardly seems like a controlled variable as well. I imagine that if you placed 10 shrimp in 10 5g buckets, you would have very different NH3 levels in each one after one week. I think ammonium chloride would be the way to go here as it will give you a much more precise result.

 

3) What are you testing the NH3/NO2/NO3 with? What is the threshold of each at which you declare the bucket has "cycled"? Do you plan on keeping the control and test bucket "double blinded"?

 

I don't mean to discourage you as it is an interesting and worthwhile endeavor, but this kind of thing needs to be rigorously replicated for any result to be meaningful. As an example, look at the level of consistency in this study performed by Dr. Rob Toonen:

 

http://www.advancedaquarist.com/2005/6/aafeature

 

I remember talking to Rob about this at the time and he was amazed at how wildly different the results were in tanks that were sitting side by side and treated "exactly the same", so much so that he discussed it in the article. Wise words to go by:

 

Even in the lab, identical aquariums set up from a single well-mixed pool of gravel and seawater without any live animals in them show a dramatic amount of variation among trials (Fig. 3). I'm sure you can imagine how much more variation there would be among tanks set up by different people in different locations and with different materials and animals! It is only by having properly replicated experiments that we can evaluate whether the treatment itself has any effect, or whether the differences among tanks are simply due to random chance. If you cannot repeat the effect that you are trying to create, then the effect obviously has little to do with the treatment that you have applied. This is one of the problems with the hobby: we too often take a single example of a successful aquarium as "proof" that some miracle design or additive really works well. However, more often than not, when you as a home aquarist try to reproduce the spectacular effect of a given aquarium, the result is considerably less spectacular. This failure is not necessarily your fault, and in fact even the person who set up the original tank will probably not be able to exactly duplicate their own success.