I've kept reef tanks for years, and what I keep coming back to is flow.

On a reef, water doesn't arrive from one place. It surges, it swings round, it comes from a different direction an hour later. In a glass box, it arrives from wherever the powerhead is stuck to the glass, and that's that. Wave makers change the speed and the timing, and some do it very well — but the water still leaves from the same spot on the same pane, every time.

I wanted something closer to the real thing, using the pumps I already had rather than buying another one. Nothing did it, because nothing moved. So I built something that carries the pump along the tank instead, and the flow start point keeps changing.

The first one has been running in my tank — a Red Sea REEFER 250 G2 — since January 2026.

I'm Dave, an engineer by trade with over 25 years in industry. I have a BEng, MSc (Eng), and I am Incorporated with the IMechE (Institution of Mechanical Engineers), registered with the UK Engineering Council.

I design, print, assemble, test, and pack Fusion Flow in the UK. No factory, no team. That's why batches are small, the lead time is four weeks, and the person who answers your email is the one who designed it.

If you'd rather have the engineering than the story, it's on the How it works page.