I run the 6 bulb 48" version of that light 31 inches from the substrait. I only run two of the bulbs though so it would be the same as your fixture. Expect the potential for all types of algea, Its a very strong light. I ended up high co2, high fert and I have frogbit and lilly pads covering the waters surface to help cut the light also, but i have ran the full spectrum of algea. I have a few tufts of brush algea on the back ground left. For me changes in lighting you can see results good or bad with in a 24 hour period where CO2 and ferts results take more time.
29g Tetra Tank
100g Planted Angel/Clown Loach
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