600Watt HPS

[whazzup]

Of course I have seen the professional test reports, but I did a small test myself with a diamond reflector (the old type with plain reflector). I first used it for one grow and measured the light at 9 fixed ponts under the reflector (HPS lamp on for one hour). Then I totally cleaned the reflector with alcohol 96% and wiped it to take off any deposits and measured again: That gave me an increase of about 5%. Unfortunately after only 3 weeks of use that 5 percent was already lost. That's the reason why the diamonds are now equipped with different reflective aluminum, but still, it's a hell of a loss for a reflector. Miro aluminum is a lot better than the standard pulled reflectors and anodized reflectors.

 

Humans are very bad at estimating light intensity, because our eyes have such a huge range and adapt well. We have for example ballasts with soft-dim function: if you switch it back or up it takes 60 seconds to gradually go from one level to another. When I switch back and forward, even 3 steps from 1150W to 600W (which takes 3 minutes to execute) people don't see a difference and wonder if it really dims. If you look at the light meter under the light however you can see it really gradually go down.

 

Metal halides look very bright, sometimes a lot brighter than HPS equivalents. That's easily explained too. They emit more light in the frequencies that our eyes are more receptive to. If you really measure the output of a MH it's always considerable less micromoles than a HPS, despite it's bright light. The yield can be compared and MH growers know the plants grow different under MH. That's in my opinion purely due to the better spectrum of the MH. The best grow results so far I had with a combination of HPS and MH and my experience with purely MH is that there is less yield. But I've seen people have about the same yield with MH or HPS.

[Frazz]

...... use 5 year old aluminum branyard reflectors. A normal reflector

MIRO aluminum .. anodized reflectors

 

heyo wazzup can you pls define the difference in the 3 examples of reflectors you have given above .. like i dunno what annodised is .. nor do i know MIRO ally , not real sure on barnyard reflectors cause in our barn we still use kerosine lamps , but their reflectors are non-existent

i have silver aluminium reflectors with a hammer-finish so what are they called

 

all very interesting thanks

[whazzup]

Well a very basic reflector is the single aluminum bent plate like this, used still by many growers. Cheap, simple and very inefficient.Called barn reflectors or stucco / hammered finish reflector (these are mostly anodized, material provides diffuse reflection). They are very basic and the reflection is not optimal, uniformity sucks actually.

 

They are also available in polished aluminum.

 

You have the cheap pressed reflectors (that damages the surface of the metal, dust and dirt can easy set, hard to clean). The better ones are anodized reflectors, which have sort of chemically polished surfaces and a protective coating. These reflectors can be re-anodized to restore the gloss.

 

 

another example, anodized reflector:

 

The better professional luminaries have replaceable reflectors (even without taking out the lamp first!). The best are made of a specially coated aluminum, called Miro aluminum. This is the highest reflective material available at the moment. Example of a miro reflector:

 

Here in a professional fixture

 

This particular reflector has a very high efficiency of 96%.

 

Other concepts of reflectors include wings and the new Triple Star reflector, which has replaceable Miro aluminum reflector plates and can be adjusted to wide, medium and deep, even asymmetrically:

The uniformity of the light is >90% in each position.

 

In the US bigger seems better, there are many air cooled reflectors available. Cooling lamps however is not always a good idea and glass creates a loss of several percents.

[Reverend]

Hi whazzup, I notice that the reflectors that are used are from the aluminium family. Is there any data on the white powder coated reflectors?

I would imagine that they could be cleaned efficiently with a little cutting compound and bought back to life. A majority of members here grow to be self sufficient and are unable financially to change reflectors and light bulbs.

[whazzup]

Hi reverend, white powder coating is much less reflective than Miro aluminum and since very long abandoned in horticultural lighting. But you don't need to replace the whole reflector, just the reflective material of the reflector. For a wing there are replacement plates available, the very cheap complete reflectors do not cost more than about 20 dollar, a professional reflector for horticulture or a replacement reflector plate kit is not more than about $30-35 retail.

 

Now what are the consequences of NOT changing your reflector: 5%+ less light after a while. And you know light=weight, so reduced yield. Let's say I don't replace my reflector and use it for about 3 years, and of that 3 years (I'll be very conservative in my estimates) my reflector has about 5% less reflectivity, how much yield would you miss? Now you also need to consider that you have direct and indirect light, and reflected amounts vary based on the type of reflector but let's say for arguments sake that you lose 2-3%. Anyone who grows and makes a small buck from the yield would be a very bad grower if they would not be able to change their reflector once a year, I do not know what you pay for pot in Australia but in Europe that would be a few grams of pot. It pays back itself quite easily. We are not growing lettuce under these lamps, but a high value crop.

 

Even if you are "just" a medicinal grower you want to optimize your yield right? A new lamp and a new reflector would then be a good investment. Using a standard SonT for example and a simple reflector for a year will cost you 10-15% of light! Have you ever heard growers complain that their first grows were much better than the ones after that? Figures, doesn't it

 

The most practical way to clean a reflector is to use alcohol, always rinse with lots of demi water and dry carefully. For calcium deposits use a light acid. Never use any material that might scratch the surface.

[Frazz]

Thanks whazz

 

[Reverend]

Cheers for the information much appreciated.

[Chato]

Some more quality info

I wiped all my shades down tonight and will be looking at replacing em asap

 

Such a simple thing to do but overlooked by most (including myself). We keep looking for ways to boost yields with all sorts of crazy ideas yet maintenance of what we already have will stop us losing yield.

 

peace

c

[whazzup]

very well said.

 

When you are checking anyway each time you restart go over all your plugs and cords, connectors and terminals too. Look for oxidation, heat marks, insulation damage.

 

Oh, and those who are still growing on a 5 year old magnetic ballast and have never done any maintenance on them: replace your capacitors AT ONCE! Your power factor mag have dropped to 0.5 and that will cause double the amount of current to run through your cables.

 

Oh well, here we go again