Whats the volume of the DT tanks & I asssume that they are "balanced" with each other somehow so water levels remain constant between them?
For my 475g build, I got alot of advice from a guy in CA that's run multiple large tanks (450, 800 & 220) on pumps that he liked, and he suggested the "Reef flow" pumps. That's the brand I use on my big DT, a snapper (2400gph) for return from the sump, and a barracuda (4300gph) for the recirculation. I like them alot, there pretty quiet, very powerful, minimal heat xfer to the water, and not bad dollar wise. I even bought a spare one of each after I got my 475 up&running, as was so impressed with them. Also the motors are american made and pretty standard so a motor overhaul could be done by most any elecrtic motor repair joint. Also the pumps are repairable by the user, and seal kits run like ~40 bucks (?) (I don't remember, but I did even buy a seal kit for the 4300 i think, just put in the spare parts closet)
This maker only makes big pumps, and the 2400gph snapper is the smallest one, and has been discontinued, with most models running in the 4000-6000 gph range.