Mars Hydro FC-8000 Review

The new Mars-Hydro FC-8000 is the biggest and possibly the best fixture from Mars. At full power it draws nearly 800 watts and can fill a 5×5 space with high density light. It can also fit in a 4×4 and I ran several 4×4 tests for growers with and without supplemental carbon dioxide. The results are impressive. It produced some of the best 5×5 and 4×4 PAR maps that I have ever made.

The FC series are the top end fixtures from Mars-Hydro. They feature Samsung LM301b (or LM301h) and Osram 660nm diodes. The FC-8000 has a total of 2968 diodes or about 3.7 diodes per watt. The diodes are powered by a high efficiency Sosen driver.

The Mars-Hydro FC-8000 has 8 adjustable LED bars. The frame on the FC-8000 is similar to the FC-E series. It comes disassembled and the spacing between the bars is adjustable. I prefer fixtures that disassemble over those that fold.

Mars-Hydro markets the FC-8000 for 4×4 or 5×5 coverage for growers with and without supplemental carbon dioxide. My tests show that it can produce excellent PAR and ePAR maps in both spaces. The 5×5 PAR map with normal density limits is one of the best 5×5 PAR maps I have made. For growers with supplemental carbon dioxide, it performs exceptionally well in a 4×4 space. If you don’t run carbon dioxide, then you will have to run it at less than full power in a 4×4 space, but it can make an amazing PAR map.

I tested it first in a 150 x 150cm (5 x 5ft) space. It delivered a maximum PAR (400-700nm) PPFD of 1000 µmol/m² at a height of 58cm (23in) above the sensor. The distribution of photon density across the PAR map is excellent. The edges are in the mid to high 700s and the corners are all about 600 µmol/m². Most fixtures that are designed for 5×5 spaces struggle to get the corners above 400 µmol/m². For growers without supplemental carbon dioxide, we recommend an average PPFD of 700 µmol/m². Again, most fixtures are not able to reach that benchmark. However, the FC-8000 delivered an impressive 793.2 µmol/m² average PPFD. That converts to a Usable PPF of 1784.7 µmol. The power draw averaged 788 watts, which gives the FC-8000 a Usable Photon Efficiency of 2.26 µmol/w.

The FC-8000 does not have any diodes that are dedicated to far-red (700-750nm) light. However, the full spectrum Samsung diodes and the 660nm Osram diodes emit a small portion of their energy in the far-red wavelengths. Recent research has shown that far-red light contributes to photosynthesis, and that ePAR (400-750nm) light is a better predictor of photosynthesis than PAR (400-700nm) light. I use an Apogee SQ-500 PAR sensor for PAR test and I also have the new Apogee SQ-610 ePAR sensor to run ePAR tests. I ran tests with both sensors with the fixture in the same position at a height of 58cm (23in).

The ePPFD values are all about 3% higher than the PPFD. The maximum ePPFD was 1025 µmol/m² and the average ePPFD was 819.8 µmol/m². The Usable ePPF was 1844.6 µmol, which gives it an excellent Usable ePAR efficiency of 2.34 µmol/w.

The Usable ePPF is 59.9 µmol higher than the Usable PPF from the PAR test. This means that the FC-8000 produces about 60 µmol of Usable energy in the far-red spectrum, which is 3.25% of the total flux.

The 5×5 PAR and ePAR maps are close to perfect for most growers. The density and distribution of light is excellent and much better than most 5×5 lights. I would not normally test a fixture this size in a 4×4 grow space. However, Mars-Hydro specifically asked me to run several 4×4 tests. A 4×4 space is less than 2/3 the size of a 5×5 space. Therefore, we expect the photon densities to increase by about 1/3. That will push the maximum PPFD above the 1000 µmol/m² limit for grows without supplemental carbon dioxide, pretty much regardless of hanging height. However, it could be ideal for growers with supplemental CO2.

Mars-Hydro requested that I test it in a 4×4 space at 12in (30.5cm) above the sensor. I thought this would be too close and lead to an intolerable hotspot in the middle and low PPFD values along the edges, but I was wrong. The PAR and ePAR maps at that height are close to perfect for growers with supplemental carbon dioxide.

In the 4×4 tests at 30.5cm (12in), the maximum PPFD was 1358 µmol/m² and the maximum ePPFD was 1404 µmol/m². Most impressively, the entire canopy is bathed in ultra-high-density light. The average PPFD is 1277.3 µmol/m² and the average ePPFD is 1324.9 µmol/m². The lowest PPFD is up at 1141 µmol/m² and the lowest ePPFD is up at 1189 µmol/m². The fixture itself is nearly touching all four walls in the 4×4 space, which certainly helps contribute to this excellent distribution of densities.

Although the space is smaller than the first tests, the fixture is hung much closer to the canopy. As a result, the Usable PPF (1839.4 µmol) and the Usable ePPF (1907.8 µmol) are higher than in the 5×5 tests at 58cm (23in). The Usable Photon Efficiencies are also higher, 2.33 µmol/w in the PAR test and 2.42 µmol/w in the ePAR test.

Mars-Hydro also asked me to run tests in this set-up with the dimmer at 75% and 50%. I obliged and ran ePAR tests with the dimmer knob set to those positions. Both maps show potential uses for the FC-8000. However, the dimming percentage was not very accurate. With the dimmer set to 75%, the FC-8000 that I tested pulled a power draw of 545 watts, which is 69% of the full power draw. With the dimmer set to 50%, the power draw was reduced to 293 watts, which is only 37% of the full power draw. If you want to recreate the distribution and densities of light in these tests, it would be best to match the power draw rather than rely on the specific dimmer positions.

The 75% ePAR test in the 4×4 space at 30.5cm (12in) produced a remarkably good ePAR map. The densities in this map are perfect for grows without supplemental carbon dioxide with the Maximum ePPFD at 1025 µmol/m². The distribution is incredible with an average ePPFD of 965.7 µmol/m², which is close to the maximum. That is because the lowest ePPFD is only about 150 µmol/m² less than the maximum. The Usable ePPF is 1390.6 µmol, which means the efficiency in this set-up is a stunning 2.55 µmol/w! These numbers are absolutely impressive. This is the most light that I have been able to fit in a 4×4 space within the limits set by ambient levels of carbon dioxide. If you want the best distribution of high-density light for your 4×4 grow without supplemental carbon dioxide, this is it! Get the FC-8000 and run it at 545 watts 12 inches above the canopy.

The 50% ePAR map also has an incredibly good distribution of light. Almost every square in the grid is in the 500 µmol/m² range. The power draw was only 293 watts (37% of full power), and the maximum ePPFD was 572 µmol/m². This would be a great level to provide to young plants at the end of the seedling stage.

The dimming tests reveal a rough relationship between the power draw and the average ePPFD for the FC-8000 in this set-up. The Average ePPFD is about 1.75x the power draw. Somewhat less at higher dimmer settings and somewhat more at lower power settings. If you have a power meter, you should be able to use that to dial in your ideal density of light in a 4×4 space.

The ambient temperature during my tests was 24 C (75F). The LED Bars hit a maximum temperature of 52.2C (126F). The driver, which was detached from the fixture, hit a maximum temperature of 62.6C (144.7F).

Overall, the Mars-Hydro FC-8000 produced some of the best 4×4 and 5×5 PAR maps I have made. For growers without supplemental carbon dioxide, it provides perfect photon densities in a 5×5 space or a 4×4 space dimmed to 75%. For growers with supplemental carbon dioxide, it will produce an excellent spread of ultra-high-density light across a 4×4 canopy. Edge and corner PPFD values above 1150 µmol/m² is impressive!

The FC-8000 is an excellent grow light. It has top end components, great build quality, generates an excellent spread of light, runs with superior efficiency, and has a great price. For the best deals shop Mars-hydro.com and use discount code CCFC.