chiming in a and question too.
Return flow is a separate calculation and 10x is actually (even though widely reccomended) mant consider that fast and run more in the 5x to 7x range. Giving the skimmer and maybe furge more time to do thier job, as a fast return rate sends particulate solids right back into the tank.
@Reefing Madness Id seen calculations of turnover that include powerhesds and return and honestly skimmed over them as it seem counter intuitive to me. Any links for dummies you can send.
I based mine on in tank movement and CM per second. As I met more reefers and looked at a lot of youtube for more species specific flow information the seem to base loosely it on that as well.
Killing the dead spots is a natural but many are basing it (on softies zoas clams) on the physical movement of the animal, ie right to where the fringes move. and then observe the animal.
So its more a physical observation and estimation then a set mathematical calculation is most often the technique use by the best reefers I know.
Totally makes stony corals a really guessing game. Thats where Im at anyway.
Also the LPS and SPS hard rule is like nutrients quite a myth as both live in amazingly different environments like depth and flow and thrive there. (deepest living photosynthetic coral in the world? an SPS, a lepto)
Im finding as I work with flow you naturally have different zones of laminar and turbulent flow. I aim for a somewhat even turbulant flow over the tank with fewest dead spots, but it always has a laminar drift to it(heading to the overflow) and thats a good thing. And the move the coral around till its happy.
Frustrating yes that there are no hard rules, but Last night I bought sps from a fellow reefer who had tricolor valeda in several spots in his tank, each looked different and had grown differently.
funny, the one he liked least had only encrusted about 6 in and had long 3in at max branches only in a few spots. Poor guy. Only encrusted 6in
