Ceramic Media

[evan47]

i have a fluval u2 filter and the box for ceramic media is about half full (as supplied).
i recently bought some extra ceramic media and intend to fill the box to about 90%. do you think that this will affect the flow rate too much?
the reason i am adding extra media is i may be getting a second tank in a couple of months and would like to use some pre-cultured media  to kick start the cycle. also, would there be any benefit in putting some spare media in a mesh bag in the corner of my tank, i think it will build up some bacteria just by sitting there or does it need to be inside the filter. 

 

[fluttermoth]

I've filled the middle box with extra ceramic media when I've run U series filters and it hasn't been an issue.
 
You're not likely to get much bacterial growth on a bag in the tank, but you should get some, and every little will help when you come to cycle your next tank.

 

[TrickySpot]

Bacteria grows best when there is high water flow, as the ammonia and nitrites come round fast and more often, so are 'eaten' quicker. Much better to get 'donation' media into the old filter, or run the entire new filter on an existing tank....I did that for 2 weeks (had 3 filters on a single tank), but cycling was super quick when I moved the 3rd filter to its new tank!
 
If you do go the whole filter route, I'd imagine you'd need to dose minute amounts of ammonia, so your main filter doesn't get lazy!! This is theoretical in my head, hopefully somebody else can advise on what would be good practice. You'd want to add just enough ammonia to emulate a bio load that's just more than your old filter by itself could handle, otherwise, when you move your new filter away, your one may be lazy and you get an ammonia spike
 
Good Luck!

 

[Gruntle]

I wouldn't be dosing extra ammonia in a fish tank just to get the bacteria to grow, you're more likely to cause issues for your fish rather than get any benefit.
 
By all means increase the amount of media in your filter. Keep an eye on your flow rate to make sure it's not choking, but I'd imagine there shouldn't be too much of an issue with ceramics.
 
When you do set up your new tank, keep an eye on your ammonia/nitrate levels in both tanks, you may experience a small spike for a few days but there shouldn't be major issues if you take less than 1/3 of the total media (ceramics, sponges, bioballs etc) from your filter.

 

[evan47]

well...... i have filled the middle chamber of the U2 completely (without cramming it in) plus i have also bought a small 50 litre filter with a spray bar and put plenty of fluval ceramic media in there as well. with the bar above the water line it gives a nice waterfall effect to airate the tank as well as adding filtration and maturing some media for the second tank, not bad for £15 at MA.