Nice that's a solid stand design
I was under the impression most hardcore stick keepers shoot for around 100× flow, not that they get it. Keep in mind head loss on the return too, it won't be as drastic as mine running 12 feet, but every fitting and size down of your plumbing will increase the r value and drop return flow, my opinion is that most people get 75-80 of the max capacity of their pump since most are rated for 1" plumbing and a few feet with no fittings. If you invest in decent phs (like all the ones you mentioned) I believe they let you turn down flow as well by not running at 100%. For me personally if I'm considering a rough turnover calculation id assume the return was getting about 75% max rating and the ph about 90(it's just not going to operate optimum all the time) don't base your calculations on max and then make the decision. If your going mostly SPS or lps I'd base the decision on that and make specific spots for the exceptions so either a mostly low flow lps tank with a specific area near the phs for some SPS or a turbulent sps tank with some shielded areas for this lps.
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