Trimming chaeto?

[gatekeeperdi]

Hi, can someone advise me how often I should trim my chaeto please? This is the first tank that I have a sump on so I have not grown chaeto before. The chaeto is growing but I'm not sure if I just let it grow until it fits the section of the sump it's in or if I should trim bits more often.
Any advise would be very much appreciated.
Thanks, Di

 

[d2mini]

I have a 22" cube with nothing else in it, with the chaeto rotating 24/7.
When the ball starts rubbing the sides and can no longer rotate, that's when I trim it back down to softball size. Otherwise its starts growing nuisance algae.

 

[heathd.hd]

+1 I Let Mine Grow Until It fills the area it's in and no longer spins. Than I just cut it right in half.