from bio balls to fuge.

[Bill S]

Always err on the side of caution. As noted above, with sufficient other forms of filtration available, removal of the bio balls didn't disturb enough to cause a problem.

As well, the problem typically associated with bio balls is that they trap detritus, and when you pick them up to remove them, it shakes years of gunk loose.

Where is the live rock you are going to replace them with coming from? A LFS, an established tank, or from elsewhere in your tank? That will make a difference. You don't want to remove part of your bio balls AND put uncured/incompletely cured live rock into your sump at the same time.

[corruption]

I would completely remove the bioball setup and just put in a tank with no baffles. Load it with brand spanking new dry sand, and fill it with ESTABLISHED LR. Have your input on one end, and put a return on some rock on the other side. Very simple. Then you can add a clamp on light and some macro and that's all you need!

I would not disagree with this approach at all, but my thought was that the idea was to reuse whats available... if he's willing to swap it all out though, this, or even a baffled sump as you wish it to be laid out, would work perfectly fine, assuming you're swapping in an established set of rock.

-Corruption

[Europhyllia]

Mom, I think you probably negated a significant swing also by doing half, waiting a few weeks for the bacteria to get where it needed to be before doing the other half. By then the rest of your system had already compensated. Besides, with the sand, rock and HOB your bioballs probably only took care of what 20% to 30% filtration for your system? If those numbers are right, using your method you only reduced capability by 10-15%.

Just thinking out loud of course.

I think you are absolutely right. The bioballs seemed kind of neglibible compared to the rest of my filtration system and that's why I figured in my case the 50% removal- monitoring-another 50% removal should be pretty safe.
I really wouldn't be able to tell the original poster what to do because I have no idea what he has in regards to filtration.

[saabtech]

wow thanks for all the quick responces. it seems to have turned into a valuable dialog for many folks here. i have thought about it and have decided that this is not at all as complicated as i first thought.
the area with the bio-balls in it is the high water level of the sump (12-14 inches). the other areas are lower water level (4-7 inches) that is where i have my skimmer.
i picked up a small ball (3-4 inch dia) of chaetomorpha and placed it in the smallest of the compartment of the sump (generally where i place the trace element blocks) and placed a small dual 9w 6700k coralife light behind it. i am going to allow it to grow and then i am going to place a section of "eggcrate" over the pump feed and place all the bio-balls into the shallower area (where the skimmer is) and then place the macro-algae into the deep section and let it grow. let it grow!!!