Saltwater aquarium cycle

I'm gathering all that I need for a 20 gallon Saltwater tank. This is my first Saltwater and need a "how-to" on cycling.

Should I cycle with sand only? Should some LR be in the tank when I start cycling? Isn't the live rock covered with denitrifying bacteria?

Once the tank is cycled, if I don't add fish right away, how do I keep feeding the bacteria culture so they don't die?

Thanks,

Julien

 

Starting the nitrogen cycle for Marine aquariums is the same as it is for Freshwater. You can use the tank to culture live rock, but keep in mind, this can be a timely process and can smell bad. The live rock, once cultured, is a tremendous biological filter for your aquarium.

 

If you at all plan on having LR, yes, you should cycle with it. However, this would be AFTER your LR is cured. Curing in the main tank is not suggested, but, can be done. Just make sure to cure the rock first and clean up COMPLETELY after. Then add the live sand and begging the cycle. Both LR and LS will grow both aerobic and anaerobic bacteria. This can become a denitrifying filter, but, that greatly depends on what kind of filtration you will have. The anaerobic/denitrifying bacteria, however, do not grow ON the LR, it actually grows inside it or deep in the LS. Regardless of the kind of filtration you will have, denitrifying bacteria are a good thing, they get rid of nitrate.

Try looking up information on the Berlin and Monaco methods. This could save you lots of money. I myself just read a little about them and hope to learn more. So if you learn anything on them, please, do tell!

 

bhcaaron - doesn't the bacteria primarily convert nitrite into nitrate with an end result of nitrogen? Your post says that it gets rid of nitrate, but doesn't the bacteria actually produce it?

In addition, do you have any experience with a plenum type (separated fine and course substrate) biological filter?

 

Aerobic bacteria are what most people are thinking of when talking about the cycle. They convert ammonia to nitrite, nitrite to nitrate, and there the process ends. Under the right conditions, you can also develop anaerobic bacteria which will take the process a bit further and convert the nitrate to harmless nitrogen. These bacteria require very low/no oxygen areas to grow, such as a deep sand bed.

 

bhcaaron - doesn't the bacteria primarily convert nitrite into nitrate with an end result of nitrogen? Your post says that it gets rid of nitrate, but doesn't the bacteria actually produce it?

In addition, do you have any experience with a plenum type (separated fine and course substrate) biological filter?

I don't have any experience whatsoever. It is only what I have been reading so far.

Aerobic bacteria are what most people are thinking of when talking about the cycle. They convert ammonia to nitrite, nitrite to nitrate, and there the process ends. Under the right conditions, you can also develop anaerobic bacteria which will take the process a bit further and convert the nitrate to harmless nitrogen. These bacteria require very low/no oxygen areas to grow, such as a deep sand bed.

That goes hand in hand with what I've read. This is why the anaerobic bacteria actually can grow within (inside of) the live rock. I don't know exactly why, however, it is that having artificial filtering reduces the changes of growing anaerobic bacteria naturally in the rock and sand.

 

Anaerobic bacteria is simply bacteria that does not utilize oxygen to live. If you have oxygen rich areas, than aerobic bacteria will dominate. A plenum type filtration system creates both oxygen void and oxygen rich areas by utilizing the surface area of different sized substates. It is a relatively new concept (when compared to an undergravel filter system).

This is how it works...when setting up your tank, you start with a few inches of fine substrate such as sand on the bottom of the aquarium. You then separate this layer using a grid and place a courser substrate on top, such as crushed coral. The bottom half produces massive amounts of anaerobic bacteria while the top half produces the aerobic type (due to water currents). The thicker your substrate, the better. This may be considered a downside if you tank is not that deep. However, believe me when I tell you, you will not have to change nearly as much water because you are not relying on the water changes to control your nitrates. The end result is a system in which the nitrogen cycle is completed, rather efficiently, through nature.

 

How many inches of substrate is considered DSB? I think I have an inch of sand in my tank right now.
Maybe I'll pick up a bag of courser sand or crushed coral and add it to the top of it to make it alittle deeper.

 

Sorry, but what is DSB?

If you decide to add crushed coral, you'll want to separate the two substrates with some type of netting so that they don't mix when you stir up or clean the top layer. The bottom layer (sand) is one that you do not want to disturb...ever. I would recommend a minimum of 4 inches of total substrate for this setup. Hope this helps.

 

I think I'll just keep it sand so its easier to maintain.
DSB is deep sand bed I believe.
I'll probably just grab a small bag of non-live sand tomorrow when I pick up the live rock and add to the bed. Dont need a whole lot with a hex tank. Small tank footprints are good for somethings.. haha

 

Hmmm I don't think I want to know Nirv! lol

Yes, DSB is Deep Sand Bed. I don't think there is an actual number to be considered deep. I know that in the past I've read about 1" and 2" and they were called shallow. Also when I've been reading about deep I've seen 4"-6". That's the best guestimation I can give. I'm planning on a six inch with the separation as Pistora mentioned.