Flow - Rule of Thumb?

[Oscar]

Is there a rule of thumb when planning flow rates for a tank in relation to water volume?

For example the display section of my tank is ~22G. Return pump is 425gph with a single koralia 1.

But the return pipe has an attached Hydor water deflector so maybe it reduces flow by 20% to 340gph. That gives me 325 + 400 = 725 or 33X turnover.

I am having a detritus issue that I blame partly on my aquascaping and low flow. What range of flow is suggested for a softie/LPS tank and what range of flow is suggested for a LPS/SPS tank?