Converting T8 to T8HO?

[TheFury]

What's up folks -

I'm in the market for a new light fixture for my grow rack - I've just expanded out onto a third shelf!

Now here is my dilemma. I will neatly bullet this out for you for your reading pleasure:

• T5HO fixtures are awesome
• T5HO fixtures generate tons of heat and draw a good deal more power than T8 fixtures
• T5HO fixtures are pricy
• My apartment has crappy wiring and I don't want to strain the electrical outlets in my grow room
• Because of said crappy wiring, I can't air condition the room (it's in my lease!) so I have to rely on fans and foggers to cool my grow space during the hottest months of summer... outside temperatures topped 105 degrees in July; I dare not guess what temperatures were inside my grow rack!
• I'm left with the tough task of finding a way to maximize the amount of light I can pump into my rack.
• My shelves are quite tall to allow my Neps room to grow; as a byproduct I'd like to be able to keep them as far away from lights as is practical which, again, means that I need lots of light.

So I've read some places that you should be able to switch T8HO bulbs into standard T8 fixtures without issues, but does this apply to all types of ballasts? I have a few pairs of those cheap Lithonia 2x 4ft T8 shop lights that you get at Home Depot for $17... will the ballasts in those be able to handle the bump up to T8HO?

Any resources you can point me to, or any advice you can offer, would be much appreciated.

Also - can any of you make a compelling argument (keep in mind that I am still highly impressionable at this stage in the game) as to why I should spring for a T5HO fixture instead of retrofitting my current lights with T8HOs?

 

[jesse]

will the ballasts in those be able to handle the bump up to T8HO?

I never heard about a technical lighthing standard called "T8 HO" and tried Google to find out more about. On the Philips website I found some information about replacements bulbs called "T8 HO". To me it looks as if "T8 HO" is just a marketing-orientated name: This is a real T8 bulb and its main advantages are a very long lifetime and in addition a very low loss of light over lifetime.

The marketing managers at Philips claim that a normal bulb loses 30% of their original lumens over lifetime and a "T8 HO" only loses 10%. So the average lumens from a normal bulb is (100+70)/2=85% of the nominal lumens and from a HO bulb it is (100+90)/2=95%. This 10% more lumens over the total lifetime is why they call the bulb HO for high output.

From the ballasts required there is no difference.

[*]T5HO fixtures generate tons of heat and draw a good deal more power than T8 fixtures
[*]T5HO fixtures are pricy
[*]My apartment has crappy wiring and I don't want to strain the electrical outlets in my grow room

The lighting efficiency does not depend on whether you are using T5 or T8 lighting. "T5 HO" bulbs give you more "lumens per length", but they also use more "watt per length" than T8 bulbs. The "lumen per watt" is very comparable between T8 and T5 HO.

The main difference is: T8 can be used with "conventional ballast" or "electronical ballast" and T5 can ONLY be used with "electronical ballast". Many cheap T8 lighting is sold until today with conventional ballast only, so they are inefficient: The conventional ballast uses a big amount of the electrical power and produces lots of heat.

If you want to have a lighting which produces little heat, you have to use electronical ballast with T8 lighting, too.

And don't underestimate optimized reflectors: A double-ellispoid clip-on reflector on the bulb can double the lighting intensity under the lamp. Such a thing like the Dennerle Trocal reflector (a product which is available for aquarists here in Germany):
http://www.dennerle.eu/global/index...category&layout=blog&id=57&Itemid=102&lang=en
Comparable optimized reflectors should also be available in the States too.

 

[TheFury]

Oh man, but there was so much talk out there on the internet(s) about T8HO being superior, I never assumed it was all made up! Thanks for clearing that up.

Those reflectors actually look like a great option. Again, I have those cheap Home Depot shop lights. I've actually lined the stock "reflectors" (a term I use loosely since they don't actually reflect anything) with reflective aluminum tape. It definitely throws more light down on to my plants, but it certainly isn't mathematically optimal as a double ellipsoid/parabolic reflector might be.

Anyone have any ideas about US-based sources for reflectors and what it might take to convert a Home Depot shop light to accept those reflectors?

Or might it be cheaper just to start from scratch....

 

[riceman]

aluminium reflectors

You can get mirror like retrofit reflectors from aquarium light suppliers but they ain't cheap. Probably cheaper in the long run to get flourescent hydroponic lights which have these mirrror reflectors and they are in T5 HO.

 

[Not a Number]

That's odd, when you compare the lumen output of T8HO/HL vs T8 the T8HO/HL are much higher.

Example:
http://www.topbulb.com/find/Product_Description.asp?intProductID=44247
initial lumens: 2850
http://www.topbulb.com/find/Product_Description.asp?intProductID=54059
Initial lumens: 3100

With single pin tubes it's even more significant:
http://www.1000bulbs.com/product/2408/F-96T8735S.html
inital lumens 5800
http://www.1000bulbs.com/product/8289/FHO-096T8735.html
inital lumens 8000

Granted the single pins here are 48 inches vs 96 inches for the single pin but we're looking at the difference between output in the same length tubes.

 

[jesse]

That's odd, when you compare the lumen output of T8HO/HL vs T8 the T8HO/HL are much higher.

Example:
http://www.topbulb.com/find/Product_Description.asp?intProductID=44247
initial lumens: 2850
http://www.topbulb.com/find/Product_Description.asp?intProductID=54059
Initial lumens: 3100

Yes, "High Lumen" ist what the marketing managers name that difference. Also here in Europe.

The difference between "High Lumen" and "Standard" ist that: "Standard" fluorescent lamps use a two-phosphor technology, "High Lumen" lamps use a three-phosphor technology. The three-phosphor lamps give more lumens and a better color rendering at the same time.

You can see it from the three-digit light color number what you get, i.e.
F32T8/741 ==> light color number 741, "7" stands for "two phosphor technology"
F32T8/841/XL31 ==> light color number 841, "8" stands for "three phosphor technology"
(In reality the "8" stands for the color rendering index, but you can only achieve an CRI of 80 and above with three phosphors used in the lamp as fluorescents).

If the first digit in the three-digit light color number is a "5", "6" or "7" then it is always a two-phosphor technology lamp. This is state-of-the-art of the year 1960 - DO NOT PURCHASE! It is a waste of electrical energy to use such lamps for plant lighting. Here in Europe, such oldfashioned lamps based on technology of 50 years ago are only used if the lamp is hardly used, such as in emergency lighting systems that have only a very short operating time. They cost a little bit less, but it doesn't pay if the lamps are turned on for significant operating times.

But if the first digit in the three-digit light color number is a "8" then it is always a three-phosphor technology lamp. Buy that!

"High Lumen" is used as a name here in Europe too.
You think that in the States "High Output" with T8 lighting means the same as "High Lumen"?

 

[MICKEY]

I had a evaporation air chiller when I lived in Brooklyn ,It didn't work great because of the humidy but it lowered the temp a little and doesn't uses a lot of electric ,they sell them at Cosco

 

[TheFury]

Ugh, I'm just doing everything I can to talk myself out of getting a T5 fixture. I should probably just spring for another pair of T8 shop lights from Home Depot. Problem is, after just having reconfigured my rack, I would have some of my Neps around 24" below the lights. Blarg.

@MICKEY - thanks for the input. I think you got the wrong thread but yes, I did actually recently purchase an evaporative cooler for my room. The thing is that the room became saturated with humidity very quickly and the cooling effect was lost entirely. I plan on returning the unit very shortly.

 

[jbradt]

I have a 3' wide mostly enclosed rack with 3 shelves under the light. The lighting is a 2' 2 bulb T5 HO fixture and a couple clip on's with CFL's. The top rack is about 18" above the top rack. The temperature on that rack has not gotten above 82/83 to my knowledge. The bottom rack is about 40-42" below the lights and seem to be getting enough light to be thriving. For my money, T5 HO is the way to go.

I've bought bulbs from this company. I plan to buy a fixture there too when I can get the money together. The prices really aren't as bad as I was expecting. https://www.liquidsun.bz/shop/index.php?main_page=index&cPath=121_9

 

[MICKEY]

thats the problem with Brooklyn to humid in summer,since I moved to Oregon haven't used air conditioner,but at dry most of the time,run humidifier year round,t5 will give you the most light