New update ... This has taken a bit of a backseat since March but I got it going again recently.
I've reworked the sump baffles, I've modded the skimmer to meshwheel, and now I use a 100micron filter sock on the sump intake. I'm now happy with the tank and removed what I hope were stumbling blocks in its ability to process bioload.
I took offline my other calcium reactor from the other tank, and replaced it with the smaller unit (left it as upflow). Using the larger reactor now, I modded it to upflow (switching the tubes at the bottom, using a T at the top of the chamber for the intake, cut some eggcrate and got a filter at the top).
It's -just- large enough to hold an entire container of LSM media now.
The recirc pump is a mag5, the feed pump is a lift pump (looks like an airpump but for water) that pushes water, and flow control via an irrigation dripline needlevalve.
Using a 5g bucket of outgoing water change water, which tested at 21ppm NO3, I cycled the reactor (@1 drop per second) on the bucket and the results look like this:
(Date/Effluent Nitrate ppm)
2007/04/29: Not tested (source water = 21ppm)
2007/05/02: 15
2007/05/03: 10
2007/05/04: 7
2007/05/05: 0 (source water now = 4ppm)
2007/05/06: 0 (source water now = 0ppm)
So ... quite an astonishing change from the previous trials. Of course this is on a small volume of water with a static nitrate condition (ie. not being produced), but still, a reduction of 21ppm to 0ppm in 7 days to me seems pretty keen.
I'm more convinced than ever before that the problem in the previous attempts was inadequate media volume.
Incidentally the lift pump seems to be the answer to producing a nice slow flowrate. It has been rock steady at 1 drop per second all week and what tickles me most is that it's a $10 item.
I moved the reactor over to my 110g tank tonight, which tested at 33ppm NO3 (there is a good chance of error on this reading as I did it with the unit uncalibrated on the high range reading, but it is definitely in the ballpark).
It will be interesting to see how it does now that it's moved over into "production mode."