hey i was looking to buy an 1000 watt DE HPS and i saw 1000 watt DE CMH fixtures

[freddyyola]

i wanted to know if anyone know or grown with an 1000 watt DE CMH before i know the singe ended 315 watts are great but i know nothing about the 1000 DE ones..

[9fingerleafs]

I was under the impression that double ended cmh where 630watts.

[freddyyola]

there are 1000 watts too or 945 to be exact heres the link to the one im thinking of getting its cheap but if it dont work out i wont out much https://www.alibaba.com/product-deta...60ed7a7bFFwDnf

[9fingerleafs]

I don’t know man. I always ask @Dr.Photon for advice on any electronic/light matters. Hopefully he can chime in

[starramus]

From some reviews I have read there appears to be excess heat problems with the multiple CMH units. I do not know this first hand only from other sources. If I were you I'd play it safe, and purchase quantity (3) of the 315 watt lights. More flexibility in that route.

[Farmall]

I'm probably misunderstanding but all of the 315 and 630s I've read about are CMH/LEC. and one of my other mistakes was getting a 1000w HPS as the output and HEAT are better with 600's. Fortunately this has a dimmer for 50% 75% and 100%. Despite a good sized room to use instead of a tent, I am pumping out a load of heat with several in series. Thankfully, its been and getting cold so I can use that heat.

Starramus makes an excellent point.

[DrPhoton]

Double ended technology does not provide any real benefits to metal halides, it is mainly sodium discharge that has significant benefits. The main benefits of double ended technology is through the reduction of harmonics and resonance which allow the increase of the pulse width or density frequency used. CMH however is a low frequency design, so naturally theres no need for double ended. Which is why the best choice here for superior efficiency, is the 1000w DE sodium discharge. A single 315CMH is more efficient than twin bulb fixtures or dual arc, which is basically what the 1000w CMH is. It looks like they have used the double ended platform to be able to integrate multiple bulbs together in the same enclosure.

The best efficiency CMH has been measured at is 1.5umol per watt with a single 315w system. The more bulbs added or the higher the power input used, the less efficient the technology is.

1000w DE systems, consistantly measure at 1.7-1.8umols per watt. The highest you can get from any gas discharge system, which is why it is still the main technology used for commercial grow applications.

There is a caveat however when using it for personal grow systems. Its a powerful light, which is designed mainly for commercial applications where it is intended to be hung relatively high. This is because of the high intensity over a small surface area and a reflector thats typically designed for such environments. As such if you anticipate on using such technologies, you must ensure you have adequate hanging height (at least 40 inches) and the grow space to go with it. For any grow room, you want to strive for 700umols of PPFD averaged (not square meter). With a 1000w DE sodium discharge fixture on a 5x5, which produces 1700umols of photon density. That provides 732 PPFD averaged. So you want to ideally have a 5x5 grow area with plent of head space to hang it.

I always recommend CMH for beginner growers or growers who are wanting to enjoy their grow with the comfort of full spectrum light. For the serious growers though i will point towards high end LEDs or super efficient gas discharge, such as 600w SE (1.5-1.6umols per watt) or 1000w DE fixtures.