It makes sense, I only look for the Kelvin rating, that's all I'm interested in. Not their opinion on whether or not it can be used as a grow bulb.

The chart below illustrates why Kelvin is not a good way to pick a grow lamp. You really want to know the lamps spectral output in relation to what wavelengths your plant requires for optimum growth. Both these lamps have a Kevin rating of 4000. The lamp on the left is CMH and the one on the right is a phosphor based. You'll notice the CMH has a much higher CRI because it's using more energy to emit in the green-yellow human vision spectrum's which of course is of far less importance to plant photosynthetic response.

My point is if you went with either one of these lamps based on Kelvin alone your plants would be exposed to very different wavelengths which would produce different results.

I ended up with a ton of research and after getting the spectral dist of diff t5 6500k bulbs I found that the cheapies are just the same as Phillips and Sylvania. I compared the TCPs (less expensive) to Phillips and Sylvania because I have vegged with both of those companies "grow lights". Hydrofarm used to supply them. I bought a case of 40 F54t5's HO for 126.00 bucks...they are working absolutely fine. I am about to order a PPFD meter, mainly for my Flower bulbs, but an added bennie will be to see exactly what the PAR output is on the fluoro's. PAR is what really matters anyway. I do know that I have had much better results vegging with t5s than Metal Halide. Produces a much more compact plant with vigorous growth than Metal Halide. I used every MH bulb out there and was never satisfied, even with the 200 dollar horti Super Blue. My point with that is that I have to agree with what TCP support said, I have used three different t5 bulbs, all 6500k (if that matters) and I have always had spectacular results.

Here is a comparison of Sylvania Grolux and the TCP bulbs I bought.




Here is what TCP customer support told me: ....one thing you should realize though, is that most bulbs use a similar, if not identical, phosphor blend to achieve a full spectrum. They just vary the proportion of the phosphors to output more strongly in different areas of the spectrum, thus creating different color temperatures. We supply bulbs to commercial greenhouses the world over and are proud to offer a quality bulb for commercial growing application and currently enjoy over a 60% market share in this area.

I agree with both of you, however, almost no one lists spectral graphs that would allow the average consumer to make a decision on the spot, let alone listing PAR on the packaging. So, what are we left with? Kelvin rating. I don't use CRI, just Kelvin (and output).

i use these guys for all my online purchases,pretty good prices on most grow equip.my 600 watt digilux hps are super cheap by the case.http://www.plantlightinghydroponics.com/t5-ge-ho-fluorescent-lamps-c-73_623.html

Great site Sixstring. Thank you. I am glad I took a chance on going with a cheaper bulbs. After years of buying into the "you get what you pay for" philosophy on bulbs, I gave Maxlume's a try and they were great. I bought half Maxlume and half Horti's and could tell absolutely no difference at all. I was going to replace them every grow because they were so cheap but I still have them in now and at first I was just going to use them for hardening off, but they were doing so well I have kept them in. The Horti's are still in also and again, I can see no difference and maybe the trich's are doing better under the cheapies.

I can't wait to buy me a PAR meter, until then the best thing we can do is share information.

Sixstring that is a great place for bulb prices. If you go and look at the Horti's this is what they have posted and this is why I will be placing an order with them. I don't think you can be more honest than this:

Starting July 1st 2010 Eye Hortilux requires us to show their Minimum Advertised Price on our website. This policy also forces us to substantially raise our minimum selling prices 50% so Hortilux can protect local Retailers selling prices. We are offering a Freight allowance on all Hortilux products that offsets the local retailers walk in purchase advantage. You may select any shipping option which is offset by the freight allowance.
Eye Hortilux has instructed their distributors to stop selling plantlightinghydroponics Hortilux branded products because we refuse to sell their products at an artificial price, established by Hortilux, that is 50% higher than our regular selling prices. Hortilux lamps will be discontinued as we run out of stock. We will be offering replacement products equal to or with better performance than Hortilux branded products at discounted prices.

Jesus. I just got done cruising that site even more this time. They really do have some fucking great prices. Damn :)

i have ordered a ton of shit from them and told alot of folks about that site and nobody has had any complaints .i had some bad digilux bulbs shipped that i kept for 6 months and when i tried them 2 didnt fire and they still replaced them for me and sent me a shipping label for free so they are A1 in my book.everything comes in unmarked boxes as well.if you try to buy anything eye hort it will say out of stock now because they sold everything,i got a case of the eye super hps for 60 bucks a poke back just before eye shut them down.i say fuck eye hort even though there bulbs rock lol.

Hortilux should be giving blowjobs along with, considering what they charge for their bulbs.

Just sayin'.

This chart is brought to us courtesy of Hortilux. The graph on the left is a CMH with a high CRI while the one on the right is a triphosphor fluoro blend with a lower CRI. The point they make, while it does not do anything to promote their lamps, is that Kelvin as a visual value (both lamps emit 4000 kelvin) can be manipulated by mfg's who prefer that consumers who base their purchasing decision on things like lumen output or kelvin will remain a reliable cash cow since there is a sizable design obsolescence factor built into some of these technologies, such as HID, that keep a steady stream of customers marching through the doors.

I thought I had mentioned it in this thread but it doesn't seem like I did. I just finished a side by side of Maxlume and Horti's and one Ushio. Absolutely no difference. Yet if you talk to Hortilux's rep, which I have, they will email you their spectal graphs "proving" their bulbs are better than the cheaper bulbs. Now, by whatever measurement they use, which I have never gotten a good explanation of "relative energy", I have never understood how I get just as good results with a 39.95 bulb vs 79.00 -119.00 hortilux. Maybe by whatever measurement they are using it might be but as far as bud in the bag, well I will never buy another hortilux and I don't trust anything from them.

Nothing personal but I do know enough that if hortilux bulbs were so much better than the competitor they could put out charts comparing PAR measured the same way reefkeepers do. I do know for a fact that I personally get much better results by vegging with T-5s regardless of what the chart shows. I do have to veg longer but I get, as I mentioned above, much better overall growth. Short internodes, stockier branches and root growth is no comparison at all, I get double the root ball in three gallon smart pots from t-5s as compared to MH, for whatever reason.