Hello all, getting back into the hobby again.. Question is from the attachment , did i figure my total head height correctly at 20.5 ft? I will have a 125 DT and a 75 gallon st.(that will hold around 35 gallons) total of 160 gal. So from what I read it would be nice to have 800gph flow.. My second question is finding an external pump that is not overkill? I looked at the reeflo gold hammerhead but that seems like a waste of power to me. Also if the photo is confusing I will be running 1.5 in pvc to the Tee and then 3/4 in the rest of the way.