LPS ( Low Pressure Sodium) Light question

Hi all. I was looking at going with a 250w HPS but the heat they put out would be a huge problem from the small space that I can use it in. Then I was thinking about using six 41w 2500k CLFs but I came across a 55w LPS light online that a store that might carry them around here and here's the stats of the LPS.

----- Philips - SOX 55 -----
Base - DC Bayonet
Bulb - T15
Life 6000 hr - 5% failures
Life 12000 hr - 20% failures
RatedAvgLife - 18000 hr
Watts - 55 w
Lamp Wattage - 56W
Lamp Voltage - 109V
Lamp Current - 0.51 A
Mercury (Hg) Content0 mg
Color Temperature - 1700 to 1800 K
Initial Lumens - 7800 Lm
Luminous Efficacy Lamp EM - 140 Lm/W
Lumen Maintenance 2000h - 102%
Lumen Maintenance 5000h - 100%


A user linked me to a Wiki of HPS and LPS but the part that I found intresting is this


Another unique property of LPS lamps is that, unlike other lamp types, they do not decline in lumen output with age. As an example, mercury vapor HID lamps become very dull towards the end of their lives, to the point of being ineffective, while continuing to consume full rated electrical use. LPS lamps, however, do increase energy usage slightly (about 10%) towards their end of life, which is generally around 18,000 hours for modern lamps.



I am worried about the amps that the 250 would draw and the heat it gives off for the space that I plan on using since people say that it will draw around 5 amps. The 6 CFLs will draw around 2.25 amps and if I was to use 4 of the 55w LPS lights I would use around 2.04 but it will also let me drop most of the lights and use 1 or 2 LPS and get a better result. Now my question is will 1700k to 1800k be to low for flowering or am I safe using that low of a K rating?

Also I was wondering what does it meen when it says Lumen Maintenance 2000h - 102% and Lumen Maintenance 5000h - 100% and how is it possible for a light to have a Lume Maintenance of 102%?

Low Pressure Sodium (LPS)

Low-Pressure Sodium are available most often in low wattages; although their lumen-to-watt output is the highest of any lamp, they function on a very narrow band on the yellow color spectrum which provides limited use to growing plants. While LP sodium lights maintain 100 percent of their lumen output throughout their life spans, they must be used, if at all, with an MH lamp to stimulate photosynthesis. Most indoor gardeners highly recommend HPS over LPS lamps.

EDIT: Copy and paste job.

Will a LPS light work for flowering though? A HPS isn't an option so its either a SOG CFLs flowering method or a LPS flowering method with a CFL UV light or a light that is 4100k to 6000k. A MH is not an option.

Will a LPS work more to my advantage if I throw in a CFL UV light and or a light that is around 4100k to 6000k with it?

"they function on a very narrow band on the yellow color spectrum which provides limited use to growing plants."

"they must be used, if at all, with an MH lamp to stimulate photosynthesis"

So you want to buy lights to grow a plant that are poorly suited to growing plants...??



Drop the idea, use CFLs, but you're still gonna have to exhaust if heat is an issue where you live.

EDIT: Just outta interest tho, where'd you get the impression all those LPS lights in an enclosed space wont produce a $h1t-load of heat?

You didn't answer my question.

I asked if I can use 1 to 2 CFLs with different spectrums to cover more of the photosynthesis range that the LPS won't cover.

I never said that I was going to use 4 of them. I was giving the numbers of how many LPS or CFLs I could run to the wattage and amps that a HPS would draw.

Im pretty sure I answered your question, I said they're bad for growing generally. They cover a basically unusable part of the spectrum, you'd be better off just buying a 200w 2700k or pair of 100w (one red, one blue spectrum) CFL's. Because with the light spectrum of those LPS you're basically wasting electricity.

Ok. If I find a 70w HPS light or a 100w HPS do I need to buy a HPS Ballast for it or can I just buy a ballast that can put out 70w to 100w depending on the bulb that I chose?

You shouldn't need a ballast for 70W

napa23 said:

You shouldn't need a ballast for 70W

Click to expand...

That's what I was thinking but CFLs, tube florescents and even on a youtube video a guy used one a 17w ballast for his 17w LPS light.

Of course you will need a ballast for a HPS...regardless of its wattage.

Harrekin said:

Of course you will need a ballast for a HPS...regardless of its wattage.

Click to expand...

Correct. Also you are correct LPS are pretty useless for growing plants. A complete 250 HPS system can be had for under 150 bucks including bulb. 70 watt yard lights can be bought for under 50 bucks at home improvement stores. Most store carry yardlights up too 150 watts in both HPS and MH.

Ok instead of making a new thread I'm going to ask it here. If I buy a MH light for veg but down grade it to CFLs when I get a HPS light for flowering will it stress them out from changing MH ro CFLs for veg?

why on earth would you buy an MH for veg, then go to cfls????? if your going to go MH why not get a 250w switchable then you just pop the bulb out and put in the HPS, and guess what if your seriously gonna grow dope you need the wattage. and that heat builds up no matter what light you use, 250 watts of cfls, LPS, HPS, MH in an enclosed space will get HOT.
and LPS bulbs are useless; the Kelvin(temperature) being way too low for optimal growth (photosynthesis) .

go with the tried and true my man, trust me.

mijola3 said:

why on earth would you buy an MH for veg, then go to cfls????? if your going to go MH why not get a 250w switchable then you just pop the bulb out and put in the HPS, and guess what if your seriously gonna grow dope you need the wattage. and that heat builds up no matter what light you use, 250 watts of cfls, LPS, HPS, MH in an enclosed space will get HOT.
and LPS bulbs are useless; the Kelvin(temperature) being way too low for optimal growth (photosynthesis) .

go with the tried and true my man, trust me.

Click to expand...

1 - I don't want to do a grow from seed to harvest. To me that's a waist of money.
2 - I already dropped the idea of going with a LPS I'm going with a HPS but I'm still not going to use a 250w light.
3 - I'm not growing to get stupid amount of yields and I don't care about the yields. I prefer to use a low wattage HPS light then using a bunch of CFLs