cycling a 125 gal

[joycerino]

I have a question regarding established filter media.

I currently have an Oscar (8-9") in a 75 gal. custom hex tank. Next week, I will be moving him to a 125 gal with another Juvi Oscar (3 1/2"), and moving my angelfish to the 75 (Currently in a 30 gal.). I will be using the gravel and filter from the 30 gal. to establish a bacteria colony in the 125. My question is, will the media from the 30 gal. be enough to support the bioload of the Oscars for an immediate move without posing any threat to my Oscars' health. I can't move the filter media over without a source of ammonia, and I can't move the Oscars over without an established bacteria colony.

Any thoughts on this one would be greatly appreciated.

[CaptnDan]

It depends on how much bioload that filter is currrently handling, really. There may be a short period of mini-cycling as the colonies increase in size, but nothing that can't be easily managed if you have set up a tank before - which obviously you have.

The bigger question would be, is the fliter going to be big enough to efficiently clean the 125g?

[joycerino]

The filter will be running with the other 2 large canister filters which haven't had a bacteria colony established. I will use the small HOB filter only until a large enough colony is established with the 2 canisters and the substrate to handle the bio-load. I just was wondering if anybody had experience with this.

[CaptnDan]

Ah, I misunderstood. I didn't realize you had the cannisters...

In that case, you should have no problems. There will likely be a bit of a mini-cycle as the established filter catches up, but in a tank that size the levels may never even get to be noticeable. The bacteria grow pretty fast. If memory serves, a colony can double in size in a matter of hours.

[EDIT] I forgot to add - I have done this a few times with smaller tanks, and I have also 'jump started' filters for friends this way.

[joycerino]

perfect, thanks so much for your help

[cshepard]

Last week I moved all the gravel, plants and the cannister filter (rated for a 60g tank) and fish (3 3" goldfish) from a 25 g to a 65g tank. The 25 was cycled, so I was convinced there would be no mini cycle - why would there be? All the same bacteria, amount of ammonia, etc. just more water.

Anyway, now I am experiencing a mini cycle - showing .25 ppm ammonia for the past 4 days. Oh well.

[joycerino]

would adding "Bio Spira" or "Fritz Turbo Start" do anything to help my cause? Has anyone had success with either of these?