Bio Cycle not happening

too large of a water change in the 29g. You need to give it a week then add a small fish just one. wait couple weeks add a couple more (2-3 fish) Do 25% water changes during this time nothing more. You will have some spikes until the tank is completely cycled. Add fish a few at a time not all at once. Some will disagree but I have never lost a fish doing this.

Side note Underwater filters are horrible in my opinion you have to take everything out to clean the filter and when you do you see all the waste that has been messing your water up. If it was me I would take that filter out and buy a small canister filter for the tank.

No offense tlaug, but they are trying a fishless cycle, as opposed to the fishy cycle you are explaining.

While im no expert in UGFs/RFUGFs I will take a guess, that when you added gravel and changed the flow you disrupted the cycle. Standard UGF will suck water down over the top of the gravel providing it with oxygen. A RFUGF pumps the water from underneath the gravel and suplying oxygen to the bottom part of the gravel. so you switched the oxygen source arround, possibly killing off some of the bacteria in the process.Also, if you added the gravel directly over the other stuff, the bacteria that were on top would now be burried, and have trouble getting oxygen. I will state again that this is just an UNeducated guess on my part, anyone with more knowledge or experience feel free to correct me.

That large water change also could have done some damage. I dont think 5ppm ammonia will kill your bacteria, since so many people use that number for the cycle. What gave you that idea?

Go get some bio-spira !!!!! I hate being patient, blech!!
While you may have hindered your bacterial growth, the fact that you were seeing some nitrite and nitrate says they were growing. You say you are at 2ppm. Is this from adding daily .5ppm? Have you still been adding that .5ppm daily and are still reading 2ppm? Just to clarify is all.

An aside, adding water from another tank will do close to nothing for your tank.

While im no expert in UGFs/RFUGFs I will take a guess, that when you added gravel and changed the flow you disrupted the cycle. Standard UGF will suck water down over the top of the gravel providing it with oxygen. A RFUGF pumps the water from underneath the gravel and suplying oxygen to the bottom part of the gravel. so you switched the oxygen source arround, possibly killing off some of the bacteria in the process.Also, if you added the gravel directly over the other stuff, the bacteria that were on top would now be burried, and have trouble getting oxygen. I will state again that this is just an UNeducated guess on my part, anyone with more knowledge or experience feel free to correct me.

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Just for clarification, the guess may seem logical, but is actually off. The flow rate through a UGF conventional or reverse is ample to supply o2 to all reaches of the substrate. Reversing flow should have no effect at all on the bacterial colony. If anything going from conventional to reverse would slighly improve the set-up, as the water pulled into the RFUG is usually higher in o2 than the water pulled into a conventional UGF. Either way in real numbers there will be no difference.


You are essentially into a fishless cycle woth no bacteria starter. This can sometimes take a while. You might try to remove small amounts of media or gravel from your other tank. The problem of course is that the other tank is only partially cycled. Removing bacteria may slow it down and keep you in frequent water change realm for longer (not desireable obviously)
The nitrites and notrates you saw could be a result of the Clear Zyme starter bacteria. These bottles of bacteria often come with or produce heavy nitrates when the bacteria die off. If you test most of them off the shelf you will find high nitrates in the bottle before it is ever added to your tank. The nitrites may truly be a sign of things starting to happen so You can be optomistic about that anyhow. All in all you are probably in good shape, just went through the long method of allowing bacteria to find it's own way in.
Dave

If you have nitrites/nitrates in your other tanks, I'd suggest using some of the filter media from one of them -- I did a fishless cycle on a 36g -- I went even further with my initial ammonia seeding -- I had 8ppm -- I have two filters on my 5g so I took the entire gunky bag from my whisper filter (took out the charcoal inside) and put it into the rear of my penguin filter in my large tank. I was eating ammonia inside of 10 days -- and after another week or so, I had gone through the nitrite spike. I used Cycle to start my bio load -- but honestly, I think it did next to nothing for me -- the key in my fishless cycle was definitely using the filter from my other tank. I've heard some level of success with bio-spira -- but I'm not convinced with any of the others. Oh yea -- I also increased the temperature in my tank while cycling -- was told that this would help -- raised the temp to about 85. Don't know what effect it had -- but it was part of my successful venture!