Mature Filter Media Vs "mature Gravel"

[lillykinloo]

Hi everyone! I've read that if I could get ahold of some mature filter media, I can fully stock my tank pretty much immediately. Does this same rule apply if I get cycled gravel and place it in a stocking in my tank? I was able to get some cycled flourite from my lfs (the fish appeared very healthy, and there were no visable snails or pests in the water). I have a 37 gallon Eclipse tank. Thank you for your advice!

 

[smmetz]

Gravel will not have as much of the bacteria in it as filter media. Also, if you get the gravel from your lfs before you have fish in your tank, what little of the bacteria that was there will die off since there is no amonia in your tank and no source of amonia. The bacteria will therefore starve and almost all die off withing a day I think. The same would be true for filter media.

If you get the gravel and very very lightly stock the tank at the same time, it might be enough bacteria to have the tank instantly cycled. I would put no more than 10 inches of small hardy fish in the tank though. Test daily for amonia nitrate and make sure there is no amonia and nitrates are steadily rising for a week straight before adding any more fish.

When you do add more fish to a lightly stocked, cycled tank - I would not add more than 50% most fish at one time. When it comes to the bacteria colony catching up, it's all about percentages. If you already have 30 inches of fish in your tank, 10 more inches will not be a very big increase in bio-load. However, if you only have 10 inches to start with, 10 more inches is doubling the load.

Anyway, good luck.

 

[lillykinloo]

Gravel will not have as much of the bacteria in it as filter media. Also, if you get the gravel from your lfs before you have fish in your tank, what little of the bacteria that was there will die off since there is no amonia in your tank and no source of amonia. The bacteria will therefore starve and almost all die off withing a day I think. The same would be true for filter media.

If you get the gravel and very very lightly stock the tank at the same time, it might be enough bacteria to have the tank instantly cycled. I would put no more than 10 inches of small hardy fish in the tank though. Test daily for amonia nitrate and make sure there is no amonia and nitrates are steadily rising for a week straight before adding any more fish.

When you do add more fish to a lightly stocked, cycled tank - I would not add more than 50% most fish at one time. When it comes to the bacteria colony catching up, it's all about percentages. If you already have 30 inches of fish in your tank, 10 more inches will not be a very big increase in bio-load. However, if you only have 10 inches to start with, 10 more inches is doubling the load.

Anyway, good luck.

Hi smmetz! Thank you for your advice! This is very helpful. Right now, I have 5 Diamond Tetras in my tank. They've been living in my tank for 4 weeks now. I've been testing the water every day, and I'm getting readings of zero ammonia, zero nitrite, and zero nitrate. My lfs said I definitely have to have an ammonia reading in the tank if fish have been living in it for 4 weeks, so he thinks my readings are wrong. But, they've tested the water twice, and the lfs is also getting a zero reading on everything. I thought adding some mature gravel might help the cycle along, and the lfs insisted that there has to be enough ammonia in the tank to support a bacteria colony. He thought that my tank has cycled, but the nitrate reading is so small, it won't register on a standard test kit. So, he suggested that I start adding fish slowly to help build up my bacteria colony to support a full stock of fish. I was nervous about doing this since I haven't seen any spikes or readings for 4 weeks, so I thought that if I added some gravel, this might enable me to safely add another fish or two to help the cycling process along. What do you think? Stupid idea? Thanks again!

 

[Tolak]

There are a lot of variables to this. It can be done with caution if you have a good amount of mature filter media. Mature bacteria will double about every 24 hours. Lets say you have a cycled & mature 55 gallon that is fully stocked, and want to run a 10 gallon. You could take 1/5 of the media from the 55, put it in the filter for the 10 gallon, and fully stock it. The bacteria in the 55 will have no problem catching up.

This is where the caution part starts. Knowing that mature bacteria double in about 24 hours you could take half the media from that 55, add it to another 55, and stock it. For the first few days you need to keep an eye on water parameters, particularly ammonia and nitrite, and be prepared to do water changes. Feed half or less of what you normally would for the first week, less food means less waste. What you would be doing to the filter media is no different than folks who change out half their filter media at a time.

As previously stated by smmetz, you have to have a source of ammonia during all of this. What you are doing is called cloning, basically taking even portions of media and fish, and dividing them up between two tanks.

If you are going to use gravel you would need a large portion if the tank was not running under gravel filtration. The gravel will help to cycle the tank quicker, but will not eliminate the cycle. The concentration of nitrifying bacteria is much greater in filter media.