Gravel Change Advice

[travelling-guppy]

Please could I get some advice in changing gravel in my Fluval Edge 23l.
I have had it for about 3 years and I want to change from white to black gravel.
Should I remove all the fish to change it or leave them in and work around them?
I want to do the thing that will stress them least.
As I think this will remove some bacteria from the system do I need to check ammonia levels and how often?
Thanks

 

[fluttermoth]

Substrate changes are always best done with the fish out.
 
You will probably lose a few bacteria that are living on the gravel, yes. So, don't feed the fish for a couple of days beforehand (so as to keep waste to a minimum), and test daily and feed sparingly for about a week afterwards. A few extra water changes might be needed while the bacterial colonies get back up to full strength.
 
If you can, and it's not too much hassle, the very best plan is to gradually remove some substrate, over a few days, until you have about a third or a quarter left in the tank, then remove the fish and strip the rest out and add the new (hope that makes sense; I'm not sure I've explained it very well!).

 

[Gvilleguy]

Fluttermoth I still wish there was a thumbs up button on posts...you explained it well!!

 

[travelling-guppy]

Thanks.That is v clear and helpful. Cheers. 

 

[Byron]

I agree to remove the fish to a temporary holding tank.  I've changed all my six tanks from gravel to sand about 2-3 years back.
 
I am not understanding the method fluttermouth described though...what is the benefit to removing part of the existing substrate, then removing the rest later, then adding the new at once?  As opposed to removing all the old and adding the new at one go?
 
Byron.

 

[fluttermoth]

I am not understanding the method fluttermouth described though...what is the benefit to removing part of the existing substrate, then removing the rest later, then adding the new at once?  As opposed to removing all the old and adding the new at one go?
 
Byron.

There can be a significant amount of nitrifying bacteria living in the top layers of gravel. If you remove all the substrate at once, you could risk a mini cycle. By removing it part at a time, you give the bacterial colonies living in the filter enough time to multiply and 'take up the slack', as it were.

 

[Byron]

 
There can be a significant amount of nitrifying bacteria living in the top layers of gravel. If you remove all the substrate at once, you could risk a mini cycle. By removing it part at a time, you give the bacterial colonies living in the filter enough time to multiply and 'take up the slack', as it were.
 

 
Yes, that is logical, thank you for explaining.  I rely on my plants and bacteria on the wood when I do these changes, since I tear the tank down completely and clean/replace filter media too.  But those inexperienced in all this are best to go slow.  Thanks again, B.

 

[fluttermoth]

Yes, I must admit, I do it all in one go when I'm changing as well, but I have heard of people having issues so, when I'm advising other people, I tend to advocate a more cautious approach

 

[travelling-guppy]

Gravel changed with green neons and red cherry shrimps safely out of the way in a bucket with the heater. It all looks much better with dark gravel. The shrimp are particularly happy and now swim circuits when they are fed. They were always a bit shy before. Thanks for the helpful advice. I didn't have any problem with the tank cycling after the change. I must have lots of helpful bacteria in the filter. Cheers!