Some tips on cycling a new tank by a shi fu.

vagabond · January 31, 2004

Below as quoted by:

About cycling process. heres a simple cycling 1 2 3 on starting a tank. Assuming its a 4ft x 2ft.

1) You'll need a deep sand bed in the main tank of at least 4 to 5 inches. Use all grade 0 if possible. Don't need to worry about sand storms as once the rocks are in, they block most of the force of the current. (smaller sand more effective as DSB). A DSB becomes mature in about 6 months and it is used to remove or reduce nitrate in the water as bacteria in the oxygen free sand bed breaks it down. In order for it to be an oxygen free area, it has to be very fine sand. For 4ft tank, I used 120kg and it barely made it to 4 inch only.

2) Remember to wash the sand. Use a super strong magnet(those magna scrubber placed in a ziplock bag will do) to remove all the iron fillings and particles as these will give you problems in future as iron is fertilizer for algae.

3) Mix salt and dump it in. I recommend a sg of 1.025 which is ideal for corals. They love high sg.

4)Let the dust settle. Should be very fast if you washed it well. It took mine 3hrs.

5) Place at least 50Kg of rocks (for 4ftx2ftx2ft). Try to use as good quality as you can afford. But these days, good quality rocks is only at most $6/kg (can buy at farm mart). I hope you dun go splurge all on super expensive tonga rocks. You just need 4 or 5 good pieces of tonga for decoration and the rest of base rock can just be normal live rocks. I didn't even use any fiji tonga rocks. They cost $18/kg by the way.

The live rocks you use will have dying sponges, crabs etc which contribute to ammonia. This is what starts the cycling process. Once ammonia is present, a kind of bacteria which feeds on ammonia will start to grow. These break ammonia down into nitrite and then another kind of bacteria will grow to feed on these nitrite which is then broken down into nitrate. Hence you detect high levels of ammonia which means cycling is starting. The moment you test that ammonia and nitrite is totally and completely not present (which usually takes about 2 weeks), cycling is balanced but not over.

It means now you can safely place fish and corals slowly into the tank. Slowly because your tank is not stable or matured yet and with every new introduced fish or coral, you need to give the bacteria time to grow and adjust to the new bioload. I recommend max of 5 corals each week and max of 3 fishes per week.

It is best to introduce these rocks as soon as possible as cycling cannot start without live rocks. Unless you used prawn meat or live sand. Basically you need the rocks to be present for the bacteria to grow in. If you have a wet dry tower, most of the bacteria will grow there hence it is a good system for high bioload (breaks down ammonia into nitrite and then into nitrates from the wastes alot faster than simply relying on live rocks...however, it traps wastes in the long run and hence becomes a nitrate factory.) I rely solely on live rocks, good skimmer, deep sand bed and refugium (algae) in my system. Its the most natural and least maintenance.

A tank is only considered stable and matured after it has not had any major crash in a year.

During the year of a new tank, you will encounter cyano or diatoms (nuisance algae) which is normal. These usually happen in the 2nd month. They will last about a month if your tank conditions are good and you know what you are doing. But this is another topic already.

Hope the above will clarify some doubts or helped to make the cycling process easier to understand.

Happy reefing.