you are obviously very experienced over a span of many years, so I hope you don't mind me picking your brain a little...
how do you like your sulpher denitrator? have you experienced any downside with using it? also please elaborate on your experience with nitrate and phosphate control with the substantial bioload you have: how you measure, your target values and methods used to lower.
you mentioned that you have experienced some heat transfer from your external pumps, is that due to the pump heating up the room and in turn heating the water? (since there is no direct contact between the water and the pump)
again, many thanks