Carl

As you say the Nexus has a maximum flow rate of 10,000 Lts/hr so you proberbly dont want to go above this figure as it will pass through too fast and the biological side might not do its job to best affect, the longer the duration of the water in contact with the biological side the better i have found, but not too slow that it takes forever to turn the whole pond over. Ive never used a Nexus but what i have read about them is, they are good if you get the flow right and put a sieve or vortex in front to reduce the load on the Nexus by separating the heavy solids before it goes into the Nexus. Are you pump or gravity fed? And you say your going direct back to the pond, are you not going to use a UV? If you dont you will block it all up with blanket weed in no time during the summer, and that can have devistating affects to the pump and filter not to mention the water quality if the filter or pump fails, plus it will be a constant battle and full time job removing the blanket weed from the pond and filter.

dannyboy1978uk

Oh I forgot to mention I will be using a uv, I'll probably go for a 50w. The pond is gravety fed and I will have two 4 inch drains, one to a nexus 200 and the other to an eazy pod.
Back on the subject of pumps I went to my local dealer gatwick koi and Gary very helpfull guy has sujested a Yamitsu Pond Pump, It seems quite a good pump on paper.

koimaster

i have one of sue and gary's koi in my pond had it shipped down to the west country from the place you know as gatwick koi. i think the running cost on these pumps are alittle higher but if it does the job hands down then you cant put a price on the saftey of your koi ...

Carl

I think the Yamitsu Pond Pumps are built like the Aquamax used to be? From what i understand the Aquamax build quality has changed so has had a few problems lately, according to a koi dealer i was speaking to, who said he has had a lot returned. But he also rated the Yamitsu.