Getting the CO2 going again has done the trick - pH back to 7.0 and I've added enough tap water to get the kH up a bit to buffer it. Thankfully no more deaths, but I lost quite a lot of fish before getting this sorted - live and learn. I've put a couple of pics in the photos section Matt - my computer skills arn't up to adding a thumbnail here! Your tank looks excellent Travis, and I agree a well planted freshwater can look just as good as a marine. Thanks, Ben.