HLG 350 Diablo or 750 Diablo: how should you size your lighting?

The choice between an HLG 350 Diablo and an HLG 750 Diablo starts with the shape of the cultivated area. The 350 is long and narrow; the 750 is broader. Two 350s can serve separate tables, but require two suspension positions and power connections. Draw the layout and assess canopy-level measurements before deciding.

Format comes before input watts

HLG publishes approximately 35 × 9.5 inches and up to 330 W for the 350 Diablo. The European 750 Diablo listing states about 95 × 69 cm and up to 715 W. Its current US namesake has different published power, PPF and efficacy, so check the manual of the European generation delivered. Physical dimensions are useful for planning; neither figure guarantees a particular PPFD distribution.

One fixture or several light sources?

Several fixtures provide flexibility around aisles, obstacles and independently operated tables. One larger fixture can simplify suspension and control above a compact, regular canopy. Mark the crop boundary, not the room's overall floor area, and allow access to fans and maintenance points. The number of lights follows the crop's documented light requirement and a comparable PPFD map.

Swipe sideways to read all criteria.

Two layout examples, with no promised coverage

Example A: two cultivated tables have a service aisle between them. A separate fixture over each table avoids lighting the aisle as if it were crop; elongated 350s are worth studying if their maps and mounting height fit. Example B: a continuous, almost square canopy may be simpler with one 750, provided it fits, the manual permits the available height and corner measurements remain suitable. These are planning examples, not HLG PPFD simulations.

Why 330 W versus 715 W is insufficient

Watts describe electrical input; PPF describes emitted photons; PPFD describes the photons delivered to each square metre of canopy. Compare maps over the same crop area, within each manual's height limits, and examine mean, minimum and edges. Add the electrical loads of all fixtures operating together and review cooling needs. The HLG selection guide provides the broader decision framework in French; links to translated measurement guides will be added when those pages are live.

Further reading : read a PPFD map · set fixture height and power.

Common questions

Do two 350s replace one 750?

Not automatically. Total watts and PPF do not describe overlap, uniformity, exact spectrum or mounting constraints. Evaluate the full layout under comparable conditions.

Should I leave room for plant growth?

Yes. Measure from the eventual canopy top and include the fixture and hangers. Follow the exact model manual.