I have recently purchased 4 of these lights. I am currently doing a side by side comparison using one Spectrum King 400+ in a 10 X 5 X 6 grow tent and a 600 watt HPS in a similar 10 X 5 X 6 grow tent. I am running 12 plants in each tent, using a single light and a Jupiter 2 light mover. Each tent has plants grown from seed, with plants placed in the grow tents at the same time, and running the same nutrients, feeding cycle, temps and pH. (100 litre nutrient reservoir feeds both grow tents) In this manner, anything that happens in one tent will naturally happen in the other tent. In each grow tent, I have three different strains, so each grow tent is identical in every way, right down to the positioning of the individual plants.
Each tent has a charcoal filter, and a 10 inch extraction fan removing stale and hot air, and a 10 inch fan introducing fresh air into the grow tent. These fans run through a controller that controls the speed of each fan, maintaining temperature and negative pressure in each grow tent.
Growing from seed, I allowed each seedling the same amount of time under the propagating lights before moving to the grow tents under the 400+ Spectrum King and the 600 watt HPS. All plants were well rooted in rockwool 1 inch cubes, then these were set into 3 inch cubes. When roots were through the 3 inch cubes, all plants were transferred into 23 litre pots, with expanded clay as the growing medium. Initially I was hand watering, while I waited for a new pump for the automated feeding system. Each pot received 2 litres of full strength nutrients every three hours while lights are on… Light cycle is 18/6.
At week 4 in the veg cycle, both rooms are virtually identical in height and width of plant. The difference is that under the Spectrum King 400+.LED, the lower areas of the plant are much more advanced that the lower levels of the plants under the HPS. My thinking is that there is better penetration from the LEDs.
So far I am pretty satisfied with the performance of the LED compared to the HPS. The heat from the HPS is at times a problem in one of the tents. The LED has no heat issues. In fact, low temperatures may be a problem as we head into the cooler months.
I will be going into flower soon, and will be interested to see what results I get from the LED. I will add to this post as time goes on, and in the end, compare results of dried product when the cycle has finished.
Just as a side note- I purchased these lights after reading up on their website, then talking to the people who make these lights. I also got onto YouTube and looked through all the videos there relating to these lights. I made my decision based on my own research. Quite a few Canadian growers are using these lights, and provide good information on the performance. When I purchased these lights, after I had allowed for the exchange rate from US to AU , the cost for 4 was almost $8000 AU. Then the import duty bill came in - another $2000 AU. SO I am pretty much committed to these lights until they pay for themselves.
I can get the DIMLUX EXTREME SERIES 630W PHILIPS CDM Ceramic Metal Halide CMH DIMMABLE BALLAST for $1700 AU but they still have the heat issues, and the power usage issues. If the Spectrum King 400+_ lights don’t do well, I will look at these as an alternative. However, if I can get a good harvest weight using LEDs, then I am happy to stick with them. Time will tell.
Until next post, stay safe.