How big can a chaeto ball get?

[whatcaneyedo]

I've been growing chaetomorpha for the last few months in my refugium under two 23W 6500K CF bulbs. Previously I grew caulerpa and then gracilaria. The Chaeto seems to have grown nearly to the size of a basketball and then stopped growing. I have more room for it to grow larger but it doesnt seem to want to get any bigger so I removed a handfull the other day. After doing some reading I also switched to two 20W 4100K CF floodlights. Does anyone get theirs to grow larger than that or does it just max out at that size? When I used to grow caulerpa it could grow large enough to fill the entire section that it was in.

I've been thinking that maybe I should give it even more light so I've been considering upgrading to MH over my fuge but that seems like it would be a little excessive.

Salinity 1.025
Phosphate 0.01 (elos)
Nitrate <1 (elos)
Constantly tumbling in a 20gal area with +/- 700gph of flow