I started my 125DT with a pair of 4's, as a temp starter.
Yesterday my Mag 5's came in. So now I got two mag 5's on one end where the heavy concentration of LR is. And to 4's on the opposite side pointing towards the middle.
The extra 3300 GPH turnover that they provide added an extra 26x turnover rate in my DT.
Combined with my 4's and my return line. Im Right around 48x-50x turnover rate in my DT. So I should be good for the indefinite future.
I'm not really a Korella fan, they are bulky and dont provide the best flow; but they most definitely are a bang for the buck poor mans power head , and are relatively reliable for the price.
If I had the cash I would get me some Vortechs. But I cant drop $1,000 the cash for a pair. One day yes, but for now Hydor is the most readily available for us regular folk.