Cycle time

That's a great question. I think the answer depends on both the quantity and state of the live sand/rock you put in the tank.

For example, if you take live rock out of another tank and immediately put it into your tank, chances are that that live rock will have no-die off and will begin doing it's magic immediately. If on the other hand you buy live rock online and have it shipped, it will most likely have considerably die off and need to be "cured" before your tank is ready to go. The worst case scenario is that the "live" rock is actually "formerly live" dry rock with a bunch of dead organic matter on it. In this case, the rock will also have to be cured and may take considerably longer before it's ready to be put back into a tank.

Live sand is the same way. It may need to be "cured" if it was shipped or came out of another tank. If it came out of a deep sand bed, it may need significant cure time...

As for tank cycle time, that will be about the same as freshwater unless you have a decent amount of fully cured live rock. In that case you may only see a very small cycle or no cycle at all.

-JB

 

The normal recommended cycle time is about 6 weeks. But depending on what you use in the tank to cycle it, it might take shorter/longer. I would say the best way to tell when you cycle is done. Would be to test the water for ammonia and nitrates. Both will spike and then drop, after they drop then you should be good to go.

 

Yes usually about 6 weeks give or take depending on what is in there. I want to clarify what Troy stated just in case you aren't super familiar with the nitrate cycle. You wait for both Ammonia and Nitrite to drop to undetectable. Nitrates will stay elevated unless they are mechanically removed with water changes or biologically removed with Live Sand, Nitrate Reactor or Macro Algae. If you wait for the Nitrates to drop without one of these methods you could be waiting forever. Wate changes of course will reduce it proportionally to how much water you replace. Ammonia goes up and starts to come down as Nitrite comes up. Then Nitrite starts coming down as Nitrate comes up.

 

6 weeks is a typical cycle. But I believe that number is given when you cycle with dry rock and new sand. Adding a good quantity of LR should reduce that time frame alot. If you add 10lbs for a 100g tank it prolly only cut that by a few days/weeks but if you add 100lb of good quality LR with little to no die off then you might cycle in a few days. I'm not sure about live sand. I used live sand when I started my tank and if I had to do it again I'd use dry sand. Sand can trap alot of phosphates. If you buy live sand from a online vender or a petstore like petco you don't know how long its been on the shelf. I was checking some of that stuff and it says its good for almost 2years. I'm no expert on bacteria but how can it survive in a closed bag, that travels in a truck in who knows what temperature, and sits on a shelf for god knows how long.