is it true?

[reef150]

Is this true that RO/DI water isnt suppoes to have ammonia? Does this mean I don't have to cycle ?

[Casey]

I have never heard that and you must cycle every tank you start up.

[USA reefer]

What casey said!

[tankgirl2]

Whoa! That's pretty confusing.

Casey, my understanding is that every time you add a new fish or other new bioload, the tank 'cycles' - that is the tank bioload is producing more waste and the bacteria populations will increase to compensate.

reef150,
Starting with RO/DI, while it's the best thing to do, doesn't prevent ammonia. The ammonia is a waste product of the fish and other critters in the tank, so the ammonia gets into the water after the water is in the tank.

Certain bacteria will break down the ammonia - turning it into nitrite. Then, different bacteria break down the nitrite into nitrate. Hence the cycle because your ammonia-eating bacteria have to build up and turn all the ammonia into nitrite. Then, and only then, will the nitrate-eating bacterial populations expand to consume the available nitrite.

If you're starting a tank with cured LR (that you're certain is cured), it will not need to be cycled - the 'curing' process means allowing any die off of organisms living on the rock to happen, so that ammonia from the decomposition of dying stuff is done and over with. The die off happens because of the transport from the ocean to some LFS or tank.

If you are going to have a barebottom tank (no sand) and the LR is fully cured you don't have to cycle in the old-fashioned sense, but you still have to add livestock one at a time over a period of time (allowing the tank to cycle to the new bioload) - otherwise you won't have enough bacteria to break down the waste products (ammonia).

If you intend to have a sandbed, cycling means allowing the bacterial populations in the sand to develop to a degree where they can handle the waste products produced by the fish. If you aren't using good live sand, you'll have to cycle the sand. Even the "live sand" you can buy at an LFS is somewhat suspect, so you should be careful.

While you may not have to cycle in the old-fashioned sense (of allowing the filled tank with sand and rocks to sit around for a few months with decomposing bits of seafood to fuel the growth of bacteria), you still do have to cycle in the sense of allowing time before you increase the load (fish population).

That's my understanding.

[Casey]

Everytime you add something the bioload will increase but if done slowly it wont hurt a thing cause the bacteria will catch up and you probably wont even notice anything.Ammonia needs to be present for bacteria to start to increase in a new setup,I am assuming he is doing a new setup so he needs to cycle especially if it is new uncured rock,ammonia comes from fish poop etc,not the ro/di unit it just makes clean water for the fish to poop in

[tankgirl2]

Originally posted by Casey
I have never heard that and you must cycle every tank you start up.

Casey, LOL! Doh - I read your reply as; I have never heard that you must cycle every tank you start up. Hence my confusion. Gotta read slower -

[Casey]

hehe no prob TG

[icebear]

LOL, and from Casey, reading that wrong i bet it was a shocker

[Casey]

Hey Heather

[tankgirl2]

Hi Heather,
Yeah, I was really confused because Casey's way smart about everything. Knew he had to be right. My eyes just weren't sending the correct message to my brain.

reef150, there's an additional sort of "cycling" that's called maturing. You don't want to add certain kinds of livestock (like anemones, for instance) to a tank until it's been running for about a year. That's so that copepods and other "middle" lifeforms have a chance to develop and thrive. If you can post a list of what you want to add the knowledgeable people can tell you how long to wait before adding them.)