Best way to change lights?

[jezzeaepi]

Hello all,
I am recieving some new lights for my tank today(hurray!). From what I have learned about lighting latey, it sound like they are going to be noticeably stronger then whats on their currently so I dont want to bleach my corals. Right now I have a bunch of lps, a few sps, a few zoa, and a xenia. The light I am using is a 192w PC hood thats about 6.5 months old. Its a real POS and since it runs so hot I am sure that the bulbs have sustained a fairly large spectral shift(althought I could be wrong). It had only one reflector, and it put most of the light in front of the tank rather then into it. The bulbs were no name bulbs and Im sure they were no PAR kings. The new light set up is a 5 bulb t5HO hood with individual refelctors with ATI/UVI bulbs. The wattage is about the same, but Im sure the PAR will double. The fixture has 3 bulbs on one switch and 2 on the other.

What is the best way to make the light switch? Heres what I have come up with:
Use just 3 of the bulbs all day, while slowly increasing the amount of time that the other 2 are on. For example. Right now my pc actinics are on for 11 hours and my pc 10k is on for 10. With the new set up Id have the 3 bulb switch on for 11 hours, and the 2 bulb switch on for 1 hour. Then in a few days Id change it to 2, and so on.
The screen method. I dont know exactly how this one works. I know it involves using screens layered on the tank, to block out part of the light, while slowly removing them over a few weeks to acclimate them. The downside to this one is it would look kind dumb for a while and Id have to go out and buy a bunch of screen. If you think its the best though, can I get a slightly better description of how to do it?
Height method. Start the hood up high, and slowly lower it over time to acclimate the corals. I like this one more then the screen one, but its less practical. Id have to somehow suspend the lights, or find something to stack up and set them on top of.


The problem with the screen and height method, is I dont have a lux meter. How would one know the correct amount of screens to use, or height to start out without being able to measure it? Too an extent the first method would benefit from a lux meter as well, but I think my estimate of (new)117w t5ho = (old)192w pc is pretty close.

Peace

 

[mfinn]

I always have liked the screen method because you set it up once and only have to do one thing every few days.
But I have always had a hood to conceal the screen material.
Here is what I do.
Cover the top of the top of the tank with a piece of eggcrate, if you don't have a glass top.
Lay 3-4 layers of the window screen material on top. Every 4 days remove one layer.
No meter is needed.

 

[LakeEd]

I think you have listed the most common ways of acclimating a tank to new lighting. Now, it is just to choose what way will work best for you.

I like the screen method personally. It is very easy, and cheap as well. In your local Home Depot or Lowe's... a roll of the nylon bugscreen material runs about $3.95. Simply put a few laywers of that bugscreen across the top of your tank, under your lights. To tell if you have enough, your tank should look slightly dimmer than it did with your old light. Then, every other day, remove one layer of that screen material. I like to use 5 layers, but there again its personal.

Before I did this, I used the slowly increasing the lighting period method, with success also. I just gave it about 3 days before upping the time.

Keep us informed as to which method you do chose, and how things are working for you!!!

 

[jezzeaepi]

Looks like Ill be making a trip to the hardware store. Thanks for the suggestions on number of screens and such, I wouldnt know where to start. Ill see how it looks with 4 layers and go from there. For some reason i was picturing having to cut and put together 4 or 5 screen windows, but just using the material and not messing with the frame construction makes it a lot easier.

Peace

 

[jezzeaepi]

I collaberated with my roomate today, and looks like I have access to a spectrometer. Im not going to set it up till firday, so I can go in on friday and take some spectral readings of each of fresh bulbs. They have only been fired for about 1 min to make sure they work. I will do this once a month to see once and for all if there is a shift in t5's and how long it takes.

Peace

 

[LakeEd]

That would be some neat information to collect!

 

[jezzeaepi]

I took my first readings tonight, but left them on the computer at the lab because I needed to get back home. Guess Ill post some data in 10 days to post spectrums between a fresh bulb and after 100 hours, which is supposed to be the "burn in" time of the bulbs. After that Ill start taking readings once a month.

Peace