Faster Fishless Cycling?

[This Younger Spouse]

Hey all:

Well, I went ahead and started the fishless cycling of a long 20-gallon for a cory tank.

Sand is in, driftwood is in, large rocks are in, dechlorinated water is in. Heater is on. LIve plants going in soon. Two filters are running, one designed for a 10 gallon and one for a 20 gallon, so I'm a bit overfiltered according to the specs, one might say.

Both filters have active filter media because we often run multiple filtration units on a single tank, giving us spares for times such as this. So of course I"ll be testing the water and won't add fish until it's appropriate, but I am wondering how much the cycle might speed up because of the established bacteria in the filters?

Thanks!

 

[eaglesaquarium]

It could speed up immensely. In theory, if you have a "spare" filter running on a tank with 30 fish - and the spare only has 1/3 the media of the total filtration, the filter is cycled fully for an immediate 10 fish stocking on a new tank. I probably wouldn't go with the full 10, but you could and just be prepared for a water change at any moment. I would be careful doing that with cories though. Probably not a good idea. All that said, the established media could very well shorten the fishless cycle significantly.

 

[KittyKat]

It might be a matter of a few days: if the filters have both been running on other tanks, they are probably ready to take fish even now.

 

[This Younger Spouse]

I tested early yesterday morning after I had the filters running overnight. I wanted a baseleline, and got:

Ammonia .30 ppm
Nitrite 0 ppm
Nitrate 0 ppm

Last night it tested at:

Ammonia .20 ppm
Nitrite 0 ppm
Nitrate 7 ppm

I'll test it again tonight, which will be 24 hours after the last test, and report.

 

[eaglesaquarium]

Are you dosing with ammonia at all?

 

[This Younger Spouse]

No, I'm just letting the mature media in the filter do its thing unimpeded. I'm in no hurry to stock this tank, so it's basically an experiement to see what mature media will do in a new tank.

 

[StandbySetting]

Leaving the mature media with no food source will do nothing, the bacteria will just die off due to starvation.

 

[eaglesaquarium]

Agreed.


You need to provide a food source. With mature media you could either just add a few fish (hardy and very small numbers) and complete a fish-in cycle with it. The fact that it is mature media should allow the addition of fish without a major spike, but maybe a small spike once or twice. You could also add ammonia in the form of fish food or pure ammonia to "feed" the filter. But, without food, the bacteria will die and the use of mature media will be completely useless.

 

[This Younger Spouse]

Thanks! I'd wondered a bit about that. My thought was to add some of TOS's guppies when the Ammonia hit 0, and that would allow the bacteria to keep going well.

 

[This Younger Spouse]

[font="arial][size="2"]Just did a quick test. Looks like less than .1 ppm ammonia, so a steady drop and almost 0. Nitrite still 0. Nitrates at 10-15 ppm. We're adding half a dozen of TOS's endlers in a few minutes. [/size][/font]
[font="arial] [/font]
[font="arial][size="2"]And thanks to eagles and SdS. Without those comments, I surely would have waited too long to do my next test, since ammonia is almost 0 right now. It appears the bacteria grow and thrive and die based on ammonia supply faster than I thought.[/size][/font]


I'll keep things updated with another test this evening and one tomorrow. And will test twice daily for the next several days.

 

[eaglesaquarium]

As with any "new" tank, be sure to be prepared for water changes at any time, just in case there is a spike. There may not ever be one, but it is better safe than sorry. Best wishes...

 

[This Younger Spouse]

Thanks, man. The bucket and siphon hose is right there by the tank, and the bathtub is in the bathroom across the hall. I figure I could do a 90 percent water change on a long 20 in about 10 minutes. Let's hope I don't need to.

 

[This Younger Spouse]

This morning:

Ammonia 0.0
Nitrite 0.0
Nitrate 10.0+ ppm

I'll keep testing it daily, but I'm going to consider it cycled, and in only 3 or so days. Substantial (some might say tremendous) shortening of the fishless cycle by using 30-gallon tank filtration and mature filter media in a 20-gallon tank. Everything in the tank was new and scrubbed, so there were no beneficial bacteria harbored in the sand, rocks or wood to help the mature media.

 

[eaglesaquarium]

The joy of mature media.