Cycling A Marine Tank

**ILuvMyGoldBarb** · 11-01-2009, 12:52 PM

This might seem like a bit of common sense but not all are aware of what is involved. Cycling a marine tank is much the same as cycling a freshwater tank with a few differences. Since there are 3 main kinds of marine tank let's look at all 3 of these and see what is involved in all 3. But first, there a few things that applies to all 3. Never cycle a marine tank with fish. This includes the ever popular Damsels. While cycling with Damsels is never recommended, you might get away with it if you are doing a Damsel tank, but otherwise they are not recommended. Next, do not use regular tank feedings with dry foods to start a cycle either. No only does the decomposing food create ammonia, but it also will fill your tank with Phosphates, and phosphates in a marine tank will give you algae fits in a hurry. Unlike freshwater tanks, the presence of phosphate in a marine tank does cause unwanted algae. Next, do not use prepackaged frozen foods such as krill for cycling a marine tank, again, these will release phosphates into your tank. If you plan to use a decomposing fish product, it is best to go to the supermarket and purchase fresh prawns (shrimp) for this purpose. These are things not to do, so lets look at things that you should do.

First, the basic Fish Only system. This is the system with just a regular filter and saltwater, no live rock, and no inverts. While this system is not recommended for the beginner, it is an option and can certainly be done. This system can be cycled in much the same way as a freshwater tank using household ammonia for a fishless cycle or the above mentioned fresh prawns.

Next is the Fish Only With Live Rock (FOWLR) tank. This tank is extremely easy to cycle. Step one: add a sufficient amount of live rock appropriate for the tank size. Step two: wait. Step three: test water regularly. In as little as 2 weeks with fully cured live rock, and as much as 8 weeks with uncured live rock. In recent years another variation on this has arisen, and it is the variation which I chose. Rather than using live rock to start your tank, dry rock can be used along with a small amount of live rock. Dry rock comes in a couple of forms. Some times it is old live rock that has been dried out for a long time and other times it is coral rock taken from a quarry. Either way, dry rock is not going to contain anything that can die and/or decompose to provide an ammonia source. The small amount of live rock that is added will provide the necessary die off to cycle the tank. There are a couple of benefits and one drawback to this method. First, this method is much cheaper than purchased your total rock volume in live rock, and second, you reduce the risk of getting some of the unwanted hitchhikers such as fireworms, and mantis shrimp. The one drawback is that you reduce the diversity of micro fauna in the tank. This is a drawback simply because all life on the reef has a purpose, and no matter weather you are doing a reef tank or not, this life is of great benefit.

Finally, the reef tank. Cycling a reef tank is virtually identical to cycling a FOWLR tank in every way except at the end. In a freshwater tank, fish only saltwater tank, and a FOWLR tank, you can start introducing fish to the system once ammonia and nitrite reach 0. In a reef tank, it is best to start with a clean up crew and corals, and for this it is best to wait until you also see nitrate reduction.

The marine environment is maintained by a precarious balance, and within the confines of an aquarium, that balance is even more precarious because everything is magnified. The longer your tank is cycled the more stable is will become as the micro fauna will reproduce and spread. Maintaining that balance is very important, but getting it off the the right start will greatly increase your chances of success with your marine aquarium.

**Northernguy** · 11-01-2009, 12:58 PM

Great write up!

That has answered a few questions I have had for awhile now!
Thanks SW Addict!

**Lady Hobbs** · 11-01-2009, 02:09 PM

WOW. An addict that makes sense!

Good job.

**bluebluecow** · 11-01-2009, 05:25 PM

brilliant can we have a sticky for this please

Liz

**ILuvMyGoldBarb** · 11-01-2009, 05:57 PM

Originally Posted by bluebluecow

can we have a sticky for this please

pssst... it already is.

**Lady Hobbs** · 11-02-2009, 01:44 AM

pssst......and was before they even posted.
lol

**totalfishservices** · 09-29-2010, 07:26 PM

i was told to put 2 damsels in to help cycle my tank but its not working 1 month in and my readings are all over the place should i take the fish out......

**ILuvMyGoldBarb** · 09-29-2010, 07:34 PM

IMO, you should never use fish to cycle a marine tank, it is simply not necessary. If you have sufficient live rock in your system, there will be a certain amount of die-off and that alone will create the ammonia needed to cycle the tank.

How do you have the tank setup and what have you been doing with it?

**totalfishservices** · 09-29-2010, 07:54 PM

ive got a 140 ltr tank with a 1000lhr exturnal filter with bio balls and ceramic medium and carbon in it,2 x 3000 lhr power heads 1x 250lhr protine skimmer,5kg of live rock, 5kg ocean rock, coral sand and finally a 25w marine t8 light... can you help .... fist 2 weeks nothing happened .. turned on skimmer on week 3 .. amonia started to rize but then everything went strange all values of no2,no3,amonia randomly changing between 0-1.25.... thanks....