Grower's Choice ROI-E720 Review

The Grower’s Choice ROI E720 is a big beautiful grow light. It is an array fixture with 8 LED bars. It offers the best coverage in a 5’ x 5’ grow space of any fixture that I have tested. It has superior efficiency, excellent distribution, and top-quality components. The ROI E720 is among the very best fixtures on the market for 5’ x 5’ coverage, and it comes in at an incredible price.

The ROI series is a collaboration between Grower’s Choice and TSL Horti Tech. The Original ROI E680 proved to be very popular with commercial and home growers. In April 2020, they launched the ROI e420 designed for smaller spaces. The ROI E720 came out in July 2020 and is already the most popular fixture in the line.

ROI stands for “Return on Investment”. The ROI series fixtures are high efficiency and will certainly generate a great return. Furthermore, the cost is only $0.63 per µmol, which is very affordable. I think the ROI series fixtures are a great investment for commercial or home growers.

The Grower’s Choice ROI series fixtures are available at many local grow shops. We also have a special online deal through the TSL Horti Tech website. They offer free shipping in the continental United States and you get a 10% Discount with code: CCFC

The Grower’s Choice ROI E720 comes fully assembled as one single piece. This is remarkable because it is huge! It measures 119 x 119cm (47” x 47”) and tips the scales at 20kg (44lbs). It is a serious piece of horticultural equipment! The LED bars are securely mounted to the frame pieces. The frame pieces fold in the center, which makes it possible to ship such a large fixture.

The ROI E720 has custom drivers for the LED bars that are integrated into the frame pieces. They are top-end high efficiency drivers, but if you did not know to look for them, you would never know they were even there. It is a clever design and done very well. However, since they are integrated into the frame there is no way to remove the drivers from the grow space.

The integrated drivers make the light easy to set up. It is truly plug and play. You get the fixture out of the box, unfold it, hang it up and plug it in. The only challenge is the considerable size and weight of the fixture. For many growers (including me), hanging this light up is a two-person job.

Grower’s Choice works directly with a top LED diode manufacturer to create their proprietary GC-3K Full Phase LED diodes. They are quality diodes. My PAR test demonstrated that they have efficiencies that rival the top end brands.

In addition to GC-3K diodes, the ROI E720 includes the famous Osram 660 nanometer chips. The spike they generate in 660 nanometer wavelength light helps drive peak photosynthesis. The spectrum produced by the ROI E720 is ideal for both vegetative and flowering growth.

The ROI e720 performed very well in my PAR tests. In the official test, I hung it at 38.5cm (15”) in a 150 x 150cm (5’ x 5’) test area. It delivered an average PPFD of 699.4 µmol/m², which matches our recommendation for an average of 700 µmol/m². The ROI e720 is the first fixture to achieve that in my 5’ x 5’ PAR test.

The 699.4 µmol/m² average PPFD means that the ROI E720 delivered a Usable PPF of 1573.8 µmol. I measured the power draw at 748 watts, which gives the ROI E720 a superior Usable Photon Efficiency of 2.10 µmol/w.

When you use our discount code (CCFC) on the TSL Horti Tech online store, the cost is about $990. That gives the Grower’s Choice ROI E720 a Cost Efficiency of only $0.63 per µmol. It is a price point which rivals the discount brands. I think it is a remarkable price for such a high-quality fixture. To some growers, $990 may still seem like a lot of money, but the E720 puts out a LOT of light.

According to the grow light calculator, with 1573.8 µmol of Usable PPF, the Grower’s Choice ROI E720 is perfect for a 150 x 150cm (5’ x 5’) grow space. However, at the hanging height of at 38.5cm (15”), the distribution of light is less than ideal. Although there are no areas above 1000 µmol/m², two of the edges on the map are mostly below 500 µmol/m². This is not a strike against the ROI e720, it is a result of the low hanging height.

In our official PAR tests, I set the hanging height such that the maximum PPFD is at 1000 µmol/m². This is the maximum density of light that plants can safely use. Setting up the official test this way ensures that I measure the maximum Usable PPF. However, some array fixtures, like the ROI E720, distribute the light so well that it requires a very low height before the hot spot hits 1000 µmol/m². The low hanging height ensures a high Usable PPF, but it hurts distribution to the edges and corners.

To improve the distribution, I raised the Grower’s Choice ROI E720 by 18cm (7”) to 56.5cm (22.25”). At that height, the Usable PPF drops to 1504.4 µmol, but the distribution is vastly improved. As you can see in the map below, at 56.5cm, the spread of light is more even and the entire canopy is bathed in high density light. The hot zone in the center drops from the 900s to the 800s, but the edges are now above 500 µmol/m².

At the higher hanging height, the photon efficiency is slightly lower, however, the improved distribution means the photosynthetic efficiency will be higher. This is because of the photosynthetic yield or “PI curve”. In short, plants use light more efficiently at lower densities. Therefore, in this case, we gain more by raising the density at the edges than we lose by lowering the density in the middle.

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From a practical perspective, this means that there is a really large range of efficient hanging heights for the ROI E720. Whereas many fixtures require a very precise height above canopy to maximize performance, the ROI E720 can be hung anywhere from 38-57cm (15”-22”) with minimal drop off in performance. This really takes the pressure off having to be precise and having a perfectly even canopy. In a 5’ x 5’ space, I would run the ROI E720 at a hanging height of about 56cm, but there are no problems until you get within 38cm.

Grower’s Choice makes a “Master Controller” unit that can control one or up to 200 fixtures. The master controller allows advanced dimming options and can power the ROI E720 through a “boost” mode to put out even more light. The boost mode is only available with the controller and it is not recommended for consistent use. Without the “Master Controller”, the ROI E720 is dimmable with a knob, which is located near one corner of the frame.

I tested the dimmer knob on the ROI E720. The dimmer knob locks into position at 25%, 50%, 75%, or 100%. It is accurate throughout the dimming range. The maximum PPFD percentage was at or just below the dial setting at each dimming position. See the data in the image below. I also ran a full PAR test with the dimmer set to 50%. That PAR map and data are also included below.

The Grower’s Choice ROI E720 is a great fixture at a great price. If you are looking for a single fixture to light a 5’ x 5’ space, the ROI E720 is an excellent choice. There are other fixtures that have a slightly higher Usable Photon Efficiency, but the ROI E720 draws more power and puts out more light.

I love that it comes fully assembled and is so easy to set up. However, be aware that the size and the weight are considerable. Once installed, it will be a joy for both gardener and plants. It produces a ton of light in an excellent spectrum and distributes it very well across the 5’ x 5’ grow space. The large range of effective hanging heights will make this light easy for growers and stress free for plants.

The Grower’s Choice ROI E720 is a commercial grade fixture designed for large scale applications. However, it is also ideally suited for any grower who wants to fully light a 5’ x 5’ space. It has superior photon efficiency, excellent distribution and an incredible price. It features top-end components and an excellent build quality, which is backed up by a 5-year warranty! The 8 gold bars will look great in any grow space. I give the Grower’s Choice ROI E720 my top recommendation.