Lighting for my new orchidarium - enough or too much?

[Ross]

One last thought, Brett, you should be seeking either "full spectrum" T5 tubes or 6500K tubes. The reef tubes are way to blue for any hope of blooming your orchids.

[Ross]

OK, another last minute thought (or 2) I went through the design phase myself (I have an artical on the home page documenting my experiments) http://www.orchidboard.com/Setting-u...om-Orchidarium

To "punch" the high intensity light from a metal halyde bulb that far into the case will cause problems at the top. Light is something you can define with physics. It falls aff at the square of the inverse of distance (hope I stated that right). So to get 1000 foot candles at 48" you would need 8000 foot candles at 12" (theoretically). This is absurd. You would fry just about any full sun cacus with that intensity. HID lights are mostly used for crops or tanks where subjects are at one certain distance from the source. This may not be the case for your setup (don't know). So why not consider two tanks? One designed for really high light subjects - one height, one light source. The second designed for lesser light plants such as Masdies, Paphs, etc., where t5s can be used. Both tanks lesser height (one "stage" of plants.) Just a thought. I've not had much luck with do it all in one tank. Light intensity is not the problem. Once I settled in on the subject plants, I determined I needed anywhere from 2000 FCs (ideal) down to 800 foot candles. So I used that with the Physics to determine the depth of the tank for the light source I had chosen. My fixtures are the same as yours with individual reflectors for each tube. Very effecient.

[s1214215]

Hi Ross

Thanks again.

After much thought, I will scale down the height of my orchidarium too. I think I will cut back to 90cm, I will have to see how it goes then with T5.

I wasnt considering using the T5 tubes I have now by the way. I just will have to get the Growlux if I want to test before I make the case.

I had originally looked at the Grand Cayman orchidarium and its height of 42" or about a metre. I see they use power compacts though. Are they stronger than T5? I used them on my 1st marine tank and they got very very hot.. I had 4 tubes at 90+ watts each. High output PC has to be imported to Australia last time I looked.

I agree, the metal halide or HQI lights worried me too. I have grown orchids in the past and am returning to the hobby. I have been keeping marine tanks for a 7 years now, so I have some knowlege of these lights. They punch out the light, but you can roast things too close to them. Currently there is a debate between metal halide users and T5 users and the T5 users are having great results with corals that they were told they would not likely be able to grow under T5 at greater depths than 60cm. Plus I saw that the light is more even and the PAR good too. So I thought to go with them with my orchids.

One thing marine aquaria has taught me, research, think it through and then some before buying and starting a project or you can pay a lot and be disappointed.

Sorry to get long winded

Thanks for the thread too. I will read over it. I have trawled the web, so I am amazed I missed it.

Brett

[Magnus A]

Brett

As a European I am amazed of how high light intensity is recommended on this and other internet sources! I would say that your 8 54W T5 will be more than enough if you find some decent tubes! Preferably 5000-6500 Kelvin full spectra....

One thing with tubes is that the emitted surface is very big and you get more "diffuse" light that enlighten your plants much more even than point sources (MH). Leaf do not shade each other the same way, and it seams that you need less FC or Lux to get sufficient light intensities. I have 4 54W T5 and my Sophronitis coccinea get more than enough light about 12 to 14 inch from the light.

The question is what is sufficient and what is optimal! Energy seems to be more expensive in Europe and therefore we tend to grow under less light.

I also heard that salt water aquariums tend to work better with T5 than MH! Even than the MH can deliver more FC or Lux per area.

[s1214215]

Hi Magnus

I agree with you on how much light is enough versus optimum. My main issue was if I would get enough light for low light orchids like Masdvallias/Phals at the bottom of the case. I am going to use Gro Lux 6500K tubes which I read have the best spectrum for plant growth.

I have decided now that I will have 85cm from lights to bottom of the case so I think I should be ok. I am getting the case made in January out of teak wood and will seal the interior with polyeurathane and silicone to make sure I dont get moisture damage.

Can you post those pics sometime of the warping you spoke of with acrylic. I am still interested to see that.

Here is a reefkeeping link and a pic of the light spread/PAR from that link. Couldnt find the right page as it goes forever - copied this pics a while ago. It displays how T5 tubes give better light in the middle, but more even punch over MH. I dont recall what colour temps the hobbyist was using and I doubt they would be appropriate to plant growth. I would like to see a similar pic demonstrating 6500K for plants and light spread/output Reef Central Online Community - T5 lamps: Fiji Purple vs. ATI Procolor


Brett

[Magnus A]

Brett
I have forgotten about the warping of acrylic I will try to take some pictures tonight.
For the color temperature in the picture the blue tube in the middle is 14000 or 20000 K I think and the rest is at least 8000 K for that application. For orchids, 6500 K is more than enough, you do not have to deal with the water that absorb the read part better than the blue part of the spectrum. This makes the blue reaching furter down through the water.....

For the light intensities I think you will have enough 85 cm from 8 54W T5. As I have a double "energy glas" in between my cabinet and my light I can´t give you any correct reedings but I think you will get around 1000fc....

[Magnus A]

Here is a picture of my warped acrylic front. Height 90 cm, difference 4 cm on top. Humidity 85-100 % RH inside 35-50 % RH outside

[Ross]

Here's a picture of mine contained with clips If you look carefully at the photo, you can see the plywood clips I use to hold the door closed. Also the acrylic strips across the door to reinforce it. They help to control the warp, but not eliminate it.

[Magnus A]

I should say that the Warping is so severe in my case that out of 5 acrylic hinges on the bottom of the front (120 cm) 3 is severly damaged and the other 2 has cracks! But as I getting myself two new cabinet I do not care at the moment.....

[s1214215]

Hi Guys

Thanks for the advice and Pics. I know that the light temps for marine would be way off

I was thinking though that the pic would demonstrate how T5 has better light spread and punch.

I am amazed by the acrylic warping. I guess as being into marine tanks, and never having seen the like it was amazing. However, marine tanks can use acrylic up to 2 inches thick - to hold water pressure and so unlikely to warp.

I am going with low iron glass as that will have less content that will reduce light values and give truer viewing. Here is a comparison pic of glass samples for my marine aquarium with 15mm normal float and Diamant low iron glass. Mind you, you would never need to use such thick glass in an orchidarium. It just shows how the green in normal glass due to iron that cuts light and good viewing if you are fussy like me hahha...