I currently have a Custom Sealife Velocity T4 as my return pump for the 30 gal wet/dry sump for my 150 gal tank. It is rated at 1200 gph with a 3ft head. With a couple of 90's and the length of my plumbing I'd say I'm getting somewhere around 1000 gph. I have dual overflow boxes, hence two supply lines coming into the tank...they just "seem" too strong. I don't know if the fish like the force from them or not. My cardinals (24 of them) found a nice less forceful area of the tank and school nicely. My hatchets (16) and rasboras (22) on the other hand , mixed together, split up, and are always swimming into the current or almost purposfully getting blown around by it. The plants aren/t getting uprooted or anything drastic like that....it just takes away from the nice look of my little schooling buddies. Over the past few days they just split up into to two groups in each front, top corner, swimming/getting blown around, over and over again. I expected the rasboras to swim more in the center of my tank. I was thinking of tuning down to around 600 gph. This would still give me a turn over of 4X. I am also adding a power reactor with a rio 200 which would add to the circulation. Any comments?
