# Need your opinion - Changing Gravel



## Benny1970 (Feb 29, 2012)

Hi all:

I am changing the gravel in one of my fish tank to ADA cause I want to make that a CO2 tank. The tank itself is already 4-5 years old 25G, with stable PH around 6.5 and HOB filter and heater. 3 weeks ago, I started hanging the new ADA gravel in extra large filter mesh bag in my other three tanks near the filter intake to try to collect as much bacteria as possible. Last Friday, I scoped out all the gravels and replace them with the ADA gravels I have been hanging in my other tanks, plus added a little bit new ADA, with the original filter with a few of the fish I am keeping in the tank. I am expecting a reading on Ammonia, but three days has passed, and I still haven't gotten any readings other than Nitrate at 40ppm which I assume it was from the original water, cause I only did a partial water change during the whole process. 

So here are my questions. 

1. How long do I have to wait for the Mini Cycle to show? In the past when I start new tanks, I always use fishless method, and Ammonia usually shows on the second, or third day. 
2. Should I overfeed the fish I am keeping in there to try to boost Ammonia?
3. Should I move my fish in there, and use the fishless cycle method to ensure the cycle does happen? If so, what about the plants I have in there, will they die due to the raised temperature?

Please give me your opinion, I am asking because I have always starting my tank from scratch, and never attempt changing gravel in an existing tank.

Thanks in advance.

Ben


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## Fishfur (Mar 4, 2012)

Why assume there will be a mini cycle ? If this tank is one that's been running and still has the filter on it running and it still has fish in it, then you should not have a mini cycle from changing gravel. I've changed gravel without any mini cycle happening.

The simplest, fastest way to cycle any brand new tank is simply to seed the filter on it from an established filter. The filter is the most important part of any cycle. Gravel no doubt has BB living in it; I think there are some on every surface as part of the biofilm, but the vast majority of them live in the filter. Had you put a new filter on, then I'd expect a cycle, but not from changing gravel.


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## Benny1970 (Feb 29, 2012)

Thanks Fishfur. I did not get a mini cycle at all. I was expecting one because the guy at my LFS told me I would have one if I change all my gravel. He said the majority of BB is in the gravel not in the filter. That's why he asked me to hang the new gravel in my other tanks to collect the BB. Anyway, thanks for your reply. 

Ben


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## Fishfur (Mar 4, 2012)

There are a lot of ideas and beliefs out there concerning BB. I ran across an interesting article the other day which calls into question quite a few things that many of us take for granted are true of our little friends, the BB.

I used to be quite sure that ALL BB lived in the filter and nowhere else. But I've learned I was wrong. But in a tank with a filter though, far more of them live in the filter than anywhere else because of the huge surface area that filter media provides for them to live on. Sure, the gravel has some BB growing on it, but compared to the surface area in the filter, nowhere near as many.

Thanks to an experiment I've been running using some small [2.5 G] planted tanks and Betta fish, [ doing only top ups, but no water changes, using no filters ] I've learned that there have to be some BB on surfaces other than the media in filters, because the water testing shows low level nitrates, but no ammonia/nitrite. The tanks have bare bottoms, so gravel cannot be where the BB are living. The only place they can be is on the glass and probably the leaves of the plants. Any solid surface in a tank likely lends itself to being colonized by BB. I learn new stuff all the time, which is part of the fun of the hobby for me.

If you're interested, here's a link to that article I found on BB.

http://www.practicalfishkeeping.co.uk/content.php?sid=4780


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## BillD (Jun 5, 2006)

In the case of the under gravel filter, most of the BB was on the gravel.No reason not to expect the gravel in any tank to at least have the surface covered. All hard surfaces in the tank can host BB, which means in a power failure or filter failure, it isn't a catastrophe.


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