Thanks Jack, that's nice of you to say so. I think it only lasted about 4 months, and it was about 1 month before I had to clean the rocks...excel, a toothbrush, and good old fashioned elbow grease, with the water level as low as I dared to make it easier. I had to do this twice, and in between it soon deteriorated to an algae covered mess despite regular maintenance, excel overdosing and high flow - about 15x volume/hr.
I think that perhaps we'd have both benefited from a Twinstar, but the jury was still out on them at the time. If I did this type of scape again I'd definitely invest in one (or build a DIY version), it'd cut the work involved down considerably.