I will find this out as he builds it and I am giving more info. I definitely will wait to buy the return pump before I know for sure. But I am planning this out so by the time I get the sump I will have everything. They are two media reactors for carbon and GFO etc. and I believe he said they are plumbed together and run on one pump separate from the return.Do the reactors have their own pumps or do they need to be plumbed in?
What kind of reactors ?