Slow Bioload Ramp-up

[Teuchter]

I have an established 55 gal aquarium containing mostly African Cichlids, although there is a large Firemouth and a rapidly growing Jack Dempsey in the tank. I recently bought a 125 gal tank with the aim of transferring the Africans to it and keeping the smaller tank for the Firemouth and Jack Dempsey (at least in the meantime until I can afford to get a bigger tank for them). In total there is 20 fish in the smaller tank, totalling 30 inches of fish. Filtration is provided by one Fluval 305 canister (rated for tanks up to 70 gal). The new tank has been running with a Fluval 405 (rated for 100 gal tanks) for almost two weeks.

Both tanks have a pH of 8.0, zero Ammonia and Nitrites. The big tank has zero Nitrates (of course) and the small tank had 30ppm Nitrates.

Now, I don’t want to go the fishless cycling route on the new tank, however I also don’t want to unduly stress my fish. I’m not in any hurry to get the fish in the bigger tank, so I hit on the idea of doing a combination of “with fish cycling” and seeding / transferring filter media.

Here’s what I’ve done so far – I transferred about 25% of the biomedia from the established tank filter to the new tank filter. I increased water changes on the small tank until nitrates were below 20, then transferred one Zebra Cichlid (2” fish) to the new tank. 12 hours after introducing the fish, an ammonia test showed zero (probably to be expected with a small fish in a big tank). Meanwhile I got a second Fluval 405 filter and set it up on the established small tank to start “cycling” it.

My plan is to closely monitor Ammonia / Nitrite levels on the new tank and keep below 0.25ppm, if indeed it gets that high. If levels remain undetectable, I may transfer another fish in a week or two.

If any of our more experienced members have experience of the “slow load-up” technique I’d love to hear about it. Do you think having just one 2” fish in a 125 gallon tank is enough to establish a small bio capability which can then be added to gradually? When will I know that the Fluval 405 canister which I’m cycling on the established tank has matured enough to transfer it across to the new tank (given that there is zero ammonia and nitrite detectable in it). Can I expect that if I transfer an established filter in combination with a very gradual transfer of fish I can populate the new tank without seeing dangerously high levels of Ammonia or Nitrite? (without the “spikes” so to speak).

Thanks,

 

[OldMan47]

I have done some filter cloning in my time Teuchter. What I generally do when I have 2 filters by the same manufacturer is take part of the established filter and swap it with some of the media that came with the new filter. Because they are both identical media, I don't lose too much by moving some media and I get a good established piece of well fitting media in the new filter. At that point I add as many fish as I figure the moved filter media can handle, much less than full stocking. I then monitor both tanks for a while before doing anything more. The old tank needs to be monitored because it has lost some of its biofilter and the new one needs to be monitored to make sure the clone has worked. I am going to my club auction this weekend and have 2 tanks that I expect to use when I get home. One will get a filter that has been hanging on an established tank for a couple of months and the other will get a Rena XP2 filter that will get media out of my XP3. Club auctions always mean new fish and no time for a set up so I walk in ready for my cycling needs.

 

[Inchworm]

Hi Teuchter

I clone tanks too. It works out well in smaller tanks and should work for a large one as well.

If you've taken out 25% of your filter media and moved it to your new tank, you should be able to move 25% of your fish too. I'd be more concerned about losing bacteria in the new tank from having too little ammonia than in the old one from having too much. That will rapidly reproduce but the bacteria in the new filter is likely to die off if it isn't fed.

 

[joshrm115]

Good Advice

 

[Teuchter]

It's reassuring to hear from folks who have cloned filters, thanks. This is the first time for me so I'm a bit wary. I tested both tanks last night and still no sign of ammonia in either, so I'm hoping that taking 25% of the media from the established tanks filter has not decreased it's capability too much. I did replace the biomedia I took from the established filter with new stuff, so hopefuly it'll be back up to full strength in a week or two.

I think I'll follow your advice and transfer another fish tonight in case I loose some of the bacteria from the media I put in the new filter by not having enough fish waste from only one fish (these are mature 2-3 inch Cichlids, but I'm feeding very sparingly). I guess if the media does die back a bit it'll not be a problem as long as it comes back to mach the load in the tank. If I'm only transferring one fish per week I'm hoping the bacteria will multiply to suit the load but as the "overload" is small (one fish) the spike won't be noticable. Well, thats the plan anyway lol.

Intrestingly enough, the Red Zebra (female) I put in the new tank appears to be much happier than it was in the smaller tank, it's out more, less shy, and digging for all it's worth. It probably thinks it's died & gone to heaven all those rocks and no need to share. I'll probably re-arrange the rocks each time I put another fish in to level the playing field