Cycle your salt tank

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Cycle your salt tank humanely without using live fish.

The humane method of cycling your tank.

One of the things that I see many new hobbyists do when starting a new tank is that they go out and get some cheap damsels or some other cheap saltwater fish and dump 4 or more into their tank to start the cycle. This may not seem like a big deal but when you consider what you’re putting those poor fish thru it’s a very big deal. Basically your making those fish live in a sewer processing plant for a few weeks until the bacteria bed can grow to a level where it can process the ammonia that is produced.

Some of the fish that you first get will not make it thru this process. It’s a horrible thought that a person would buy a fish with the intent to put them in conditions where there is a high % of mortality. There is a better way.


Since we already know that we need ammonia before we can have ammonia removing bacteria and that ammonia is toxic to fish we have a hard paradox of needing ammonia to remove ammonia yet ammonia could kill the very thing we put in our tank to produce ammonia.

To keep from having this issue I advise the use of the “Fishless method of cycling”.

To use the fishless method of cycling your tank you have to first get all of your tank up and running with saltwater just like you would if you where going to add fish. Instead of running off to the local fish store to get some unlucky volunteers to start your cycle you take a trip to the local grocery store. That’s correct, the grocery store. Go to the back where they sell seafood and try to find some RAW SHRIMP, make sure its raw and as unprocessed as possible. You don’t want precooked or seasoned shrimp. Depending on the size of your tank you may need as few as one (up to 30 gal) or as many as three (120 gal or larger). If you cant find raw shrimp then look for some other form of raw seafood.

Take you’re new found loot back home and drop it in the tank. Now you get to watch nature take her course with your fresh seafood. After a day or two it should start to breakdown in the warm saltwater. This process is the exact same as fish producing waste or fish food breaking down.

If you don’t have an ammonia, nitrite, nitrate test kit(s) then at this stage in the game you should go out and get some, as you will need them during the cycling process. After a few days you should start taking ammonia tests of the water. You should see the ammonia begin to rise as the shrimp rots away. As the ammonia levels rise you should see them peek after a week or maybe a little longer. After about a week you can start to test for nitrite. As the ammonia levels begin their decline the nitrite levels should begin to rise. During this time the conditions in the tank are not beneficial to life other than the bacteria that is starting to grow and reproduce in your tank. This bacterium is needed to keep your tank ammonia free. After a few weeks the ammonia levels should be almost nonexistent again and the nitrite levels should be on the decline. At this time the shrimp may or may not be visible anymore. When the tank tests negative (0.00) for ammonia and nitrite your ready for your first fish or two.

New tanks should only have fish introduced in very limited numbers. Every item you add to your tank will increase your bio load to some degree. Some additions will affect the bio load more than others. For example, a 2 fish will increase your bio load a lot more than a handful of hermits and snails. A lionfish will increase your bio load more than other fish of the same size, as they are messy eaters. With every addition to your tank the bacteria has to increase to support the higher level of ammonia production. If you increase the bio load to quickly it could cause an ammonia spike. If the ammonia spike is to large then the inhabitants of the tank will either be stressed or killed.

Should you have any questions or comments about this article please feel free to post in the Saltwater & Reef – General Discussion forum.

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