thanks, i stuck to my old slower flowrate pump.
i just added a small wavemaker to increase flowrate in main tank, as I've read slower flow rate in sump gives more time for BB to be in contact with the water?
and the wavemaker increases the flow rate in main tank which will act as mechanical filtration pushing poop to overflow .
i think better to switch to 2500L pump for your tank
arent the rays stressed from the current?