Plumbing question (Pipe Size)

[mterrace]

I am setting up a new 90 gallon all-glass Megaflow - it is pre-drilled for 1" and 3/4" bulkheads. I am plumbing this into a wet/dry in my basement. I also have a 55 gallon fuge that I am goin to use...
I am planning on hooking it up like this...out of the 90 gallon, into the wet/dry (gravity fed) - gravity fed into the 55, and then pump back up to the 90 (through a chiller). I have an Iwaki MD-70RLT pump, with 1" in/outs...
So my feed from the 90 will be 1" and my return will end up being 3/4" --- Where should I reduce the pump output to 3/4" - at the pump, or at the tank?
How does this sound? Gravity fed vs two pumps....
Thanks in advance,
Mark

 

[squidd]

If you can...run 1" all the way up and set return OTT (over the top) of tank... You get the benifit of flow thru 1" and an easy place to put an anti-siphon hole in drain line...
If you insist on running thru "in tank" 3/4 return... run 1" all the way up to last possible joint to maximixe flow to tank...
Two pump systems never work.. so gravity down and pump up is only option

 

[psusocr1]

squidd beat me too it but i would highly reccomend using all the holes drilled as drains and then like mentiond return over the top.. this way not only will it have all the benefits that squidd mentions but you can push more water through the tank giving you better filtrationa nd water movement

 

[mterrace]

Thanks for the quick responses!