Everyone says 10 x flow so we use multiple canister filters and pumps on a tank to try and reach that magic number but is a literal 10 x flow needed? Wouldn't well directed flow with a filter that moves 3-5x the water volume be good enough?
I am going the opposite direction, building off what has been learned on the reef side the past 5-10 years about flow and the effects of dissolving organics. Let's think through the phases of a typical setup. Yes, I know I'm generalizing here:
1) Month 1 and 2:
Filter is not yet mature. Things have to settle in.
2) Months 2-6:
This is the sweet spot. From months 2-6, things go swimmingly as filter is mature and flow is still good.
3) Months 6+:
Decline. Plants obstruct flow. Junk caught in the filter slows flow. CO2 is less evenly distributed. All those organics that have slowly permeated the low flow areas of the tank are starting to feed the latest algae of the week. Ever notice that algae often pops up first in areas of reduced flow?
How can you combat the typical decline? My goals are two fold - get the good stuff (CO2 and current) to every nook and corner of the tank and get the bad stuff (any semi-buoyant organic) from the display into a healthy "oversized" filter where it can be easily processed/removed.
No, I'm not talking about shooting high pressure jets through the tank. Think vortech pumps, spraybars with larger holes, strategically placed lily pipes, and so on.