Lesson learned - Orchid Board

Ross · #1 12-11-2007, 04:14 PM

Here's a heads-up for those that are as non-astute as I am

Be careful about maintaining the glazing that may (or may not) seperate your lights from the plants. In my case I had an extra piece of glass lieing on top of the acrylic case for my orchidarium. I have not been careful to keep it clean. I just received my new light meter Light Meters, 840006,840020,21,22 (I got the 840020)

At first (after I zero'd it) it registered a dismal 700 foot-candles at the leaf surfaces of the high-light lovers near the lights and only 1500 lux directly below the 5000 lux tubes. What's up?

I tried several "coiled bulb" compact florescents I knew were reliable and they were fine - nice high readings.

I decided to remove the extra glass and guess what? It was filthy! All gray with dust and whatever. I removed it entirely and replaced it with two thin aluminum tubes to keep the bulbs from contacting the case top and then took a new reading. Well, my subjective reading was this is "lots brighter", and the meter read over 2000 foot candles next to the plants. That's a change from 700+FC --> 2000FC just by removing the clear glass. Guess that gives my Dendrobium aberrans a new lease on life and if I were a betting person, I would bet it will now bud out and bloom.

Becca · #2 12-11-2007, 05:15 PM

Ross,
Not to long ago I cleaned the film off of my acrylic glass that was left behind from the humidity of the fogger I used to use. But I did test with a light meter before and after and got the same reading so I didn't mention it to anyone on here cuz I thought I was being silly about worrying about that. I do plan on keeping the acrylic glass between the lights and the orchids cleaned even though I didn't get a different reading. Part of me thinks my light meter is just wacky!

Becca · #3 12-11-2007, 05:26 PM

Umm....I think there is a problem! I didn't post three of the same reply!

Ocelaris · #4 12-12-2007, 04:55 PM

Do you have the lights physically seperate from your growing space to keep the heat out? I plan on having something in between the lights and the growth space for that reason... How do you have your lights vented so they don't heat up and melt the acrylic on top? Fans blowing?

I plan on having a 4 foot tall growth space, so I'm not totally confident on PC bulbs being able to penetrate that distance, so I'd like to have a combination of Metal Halide and PC... but again, the heat build up, and ease of cleaning are an issue.

Ross · #5 12-12-2007, 05:08 PM

Quote:

Originally Posted by Ocelaris

Do you have the lights physically seperate from your growing space to keep the heat out? I plan on having something in between the lights and the growth space for that reason... How do you have your lights vented so they don't heat up and melt the acrylic on top? Fans blowing?

I plan on having a 4 foot tall growth space, so I'm not totally confident on PC bulbs being able to penetrate that distance, so I'd like to have a combination of Metal Halide and PC... but again, the heat build up, and ease of cleaning are an issue.

Question 1, Bulbs seperate, yes - see

where you can see the fixture above the tank. There is a fan blowing through the fixture all the time it is on (it's on the same timer) see -

If you look carefully you can see the fan at upper right.

I use t5 Florescents (a bank of 4 ea 47" bulbs) and get a pretty reasonable foot-candle response from them. They do run warm (not as warm as MH or sodium) but still they run 95 degrees F. The fan does a decent job of blowing away the heat before it gets to the tank. The tank runs about 3-4 degrees F hotter at top than bottom. Bottom is usually same as room (basement) temperature. For instance, today I read basement ambient temp of 68.6F and in tank I read (top) 72.8F and (bottom) 69.5F That's after 10 hours lights-on.

Becca · #6 12-12-2007, 05:32 PM

I do not have any fans blowing on my lights. My large orchidarium doesn't get any hotter then the mid 80's, they are not T5 lights, but are something like CFL's so they don't heat up to hot like the T5's. On my small orchidarium, I have the T5 lights, thanks to Ross! They do run around 95 and I have a piece of acrylic between the orchids and the lights, but again no fan on the lights....the smaller orchidarium does heat up to about the lower 90's and I am okay with that for now, the acrylic is very thin, I wonder if a thicker piece would help, like what I have in the larger orchidarium?

Ross · #7 12-12-2007, 06:06 PM

Quote:

Originally Posted by RPfeiffer

I wonder if a thicker piece would help, like what I have in the larger orchidarium?

Thicker won't help. If you have a heat problem (I think not), then you need to blow a fan across the lights like this --

Ocelaris · #8 12-12-2007, 07:32 PM

rsfrid, do you know how much light you are getting quantitatively down to the bottom of your tank? It might behoove me to look at the T-5 alternative, although I tend to favor the CF from AHsupply.com because they're a nice package, DIY, and relatively cheap for the setup... The T-5 setups I've seen are all prepackaged and in the 300$ price range for the amount of light I'm looking to put in this new tank.

Ross · #9 12-12-2007, 08:41 PM

Quote:

Originally Posted by Ocelaris

rsfrid, do you know how much light you are getting quantitatively down to the bottom of your tank? It might behoove me to look at the T-5 alternative, although I tend to favor the CF from AHsupply.com because they're a nice package, DIY, and relatively cheap for the setup... The T-5 setups I've seen are all prepackaged and in the 300$ price range for the amount of light I'm looking to put in this new tank.

I will measure tomorrow. Right now is "lights out" period so I can't measure, but I remember approx 500FC at bottom of tank. I am using these lights .: Sunlight Supply - horticulture and aquarium lighting systems :. Website

Call me Ross

Ocelaris · #10 12-12-2007, 08:52 PM

That's a pretty good amount of light... equivalent to a 250w metal halide roughly... with better distribution for sure. I don't need an exact, but I'm just curious how fluorescent lights do at say 3 feet away, which is about the max mine will be.

Your tank is definetly prettier than what I'm expecting to end up with, but none-the-less something to strive for. I really like the all acrylic corners.

I'm going to try and grow ascocendas and mini cats, maybe some full sized catts if space allows, something that requires a good amount of light.