On growers’ forums, when people ask about reliable, affordable LED lights the name MarsHydro usually comes up sooner or later—and rightly so. The cheaper, entry level lights are perfect for getting started or kitting out a large grow space on a budget. But what about the top of Mars’s range?

What do you get when you spring for one of Mars’s best lights, the Mars Pro II Series?

In this review we’re going to take a look at the full spectrum MarsHydro Mars Pro II Series Epistar 400W LED grow light, with separate Bloom and Grow switches. If you want to replace a 250W HID light and cover a flowering area of 2’x2’, you’ll want to read on.

And even if you want to cover a larger area… still keep reading.

Because lights in the Pro II Series can be connected together. And, of course, larger models are available—five of them, including a couple with CREE LED chips for that extra bit of quality.

MarsHydro Mars Pro II Epistar 400W: What do you get for your money?

MarsHydro Mars Pro II Series 400W - Mars Pro II 80 Review

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In a nutshell: intensity, even coverage and value for money. Even Mars’s flagship models are accessibly priced.

The Mars Pro II Epistar 400W (sometimes listed as the Mars Pro II 80), as its name suggests, packs 80 high intensity 5W Epistar LED chips.

Having LED chips from a respectable brand like Epistar is always a good start, of course.

And in addition to that, Mars sets the chips in reflector cups to ensure an even footprint and good spectrum mixing, with minimal light loss.

With no secondary lenses, too, there’s also less chance of chips burning out.

The chips are also zener-protected, so one chip failing won’t cause the whole light to fail.

Pro II lights are full spectrum, so you can use this one for all grow stages. When you turn on the Bloom switch, it adds plenty of red light (including infrared (IR)) for a good flowering boost.

And having separate Bloom and Grow switches allows you the possibility of saving some money on energy costs, as well as a little bit of flexibility in how you grow.

Unlike its other lights, the Mars Pro II Series are designed to be connectible with a flexible U connector. While not quite as handy as being able to daisy-chain the lights, this feature still makes it easier to hang multiple units and get the best footprint out of them.

Mars Pro II Series lights are connectable

Mars Pro II Series lights are connectible

Brightness and intensity

MarsHydro Mars Pro II Series 400W PAR values

PAR values for the Mars Pro II Epistar 400W

As mentioned, the Mars Pro II Series 400W is capable of replacing a 250W HID grow light, while drawing only around 170W at the wall.

But what about those all-important PAR figures?

  • 752 umols when hung at 12” (flowering stage)
  • 421 umols at 18” (veg stage)
  • 203 umols at 24” (seedling/veg stage)

By way of comparison, those are better figures than similar sized lights in Mars’s cheaper ranges of grow lights.

Or to put it another way, paying a few extra dollars for a Mars Pro II will get you that extra bit of intensity for bigger, tastier buds.

Reflector cups around the chips help ensure an even footprint without hotspots too.

Though much more directional than HID lights, LEDs do still need a little focusing to get the best out of them. So we think the slight efficiency loss from a well designed reflector is an acceptable trade-off. Especially as Mars use this method rather than lenses, which can sometimes lead to LEDs burning out.

Footprint diagram for the Mars Pro II Epistar 400W

Mars Pro II Epistar 80’s footprint

What else do we like?

Another big advantage the Pro II Series has over some other MarsHydro lights is a longer warranty—the Mars Pro II Epistar 400W comes with a 3 year manufacturer warranty, serviced by local repair centers (for most of our readers).

Here’s what we also like:

  • 50,000 to 100,000 hour lifespan
  • Spectrum includes infrared (IR) for higher yields
  • Quiet (49.8 dB), efficient heat management
  • Compatible with timers, for easy dark/light schedule management
  • ETL/CE/RoHS certified for safety—parts inside are fireproof
  • Comes with hanging kit, instructions and region-specific power cord

Any downsides?

Well, this light is that little bit more expensive than some of Mars’s other lights.

On the other hand, it is brighter than the equivalent cheaper models and the footprint is more even than the cheapest. So you do get value for money.

Some growers would probably prefer dimmers for that extra bit of control over brightness and spectrum.

And some will prefer a light with UV.

UV light stimulates resin production, for more THC and terpenes. But UV chips are currently the least efficient and least long lasting LEDs and lights with UV tend to be a little more expensive.

Our overall verdict

The Mars Pro II Series is MarsHydro’s most expensive range of lights… but it’s still MarsHydro, so they’re still well within the price range of most growers.

And we think that extra expense is worth it, because it’s backed up by more intensity and a more even footprint.

Not to mention a longer warranty, should you need it. And the option of a couple of models with CREE LEDs.

As for the Mars Pro II Epistar 400W itself…

Like the rest of the Series, great value for money—and even better value if you buy it from the DazzleKat store.