View Full Version : T5 Par & Bulb Selection

08-09-2007, 01:50 PM
As you can tell from my last couple threads, I'm contemplating a new lighting system! I've decided that a nice T5 set-up may be my best bet, all things considered.

I have the opportunity to buy a 36" 8x39W Tek fixture. That's a lot of light. I've read a lot about the different PAR values for MH bulbs, but haven't found much on their T5 counterparts. Does anyone have any information on that?

As well, if you were running 8 bulbs, which T5s would you choose and why?

08-09-2007, 02:01 PM
Well, I found something (http://reefcentral.com/forums/showthread.php?s=&threadid=918935) on RC. But anyone have any other personal experience? Recommendations for bulb selection?

Reefer Rob
08-09-2007, 02:51 PM
I think you found the best information on T5 par that's out there. When I ran all T5s I liked the look of 50/50 blue+ and Aquablue, but T5s are all about taste, it may not be what you like. When you order your bulbs get 1 extra Aquablue and a GE daylight so you can play with your color temperature a bit.

T5s also shift toward the red spectrum as they age a bit, so what looks good when they're new may not look good 3 months from now, so you may want to switch your bulbs a bit then.

08-09-2007, 03:45 PM
I'm currently running 2 of the ATI blue plus bulbs, and the difference between those and the generic ones my light came with it amazing.

08-09-2007, 04:42 PM
I had T5 lighting & thought I was happy until I just started using a MH unit . I perfer the MH system alot better, but I was only running (4) 39w. The corals seem perkyer & I like the light shimmer . Also (1) 250w HQI bulb is alot cheaper than (8) 39w T5 bulbs. Good Luck .

08-09-2007, 08:34 PM

scroll down for pics

08-10-2007, 12:13 AM

scroll down for pics

GREAT thread. Thanks!

08-10-2007, 10:55 PM
what a joke of a thread. if you compare PAR at center line on the bottom of the tank with either light the MH will be way higher than the T5. every T5 advocate uses the point source of a MH to his advantage to make it look like it has a lower output.

I was testing at 23" of water and 6" of air and my PAR was still over 500 with MH, the problem is if you look at the pictures it is a very unfair comparison. he had multiple T5 tubes so no matter where he measures he is right under one (take them all out and put one across the middle and see what happens to his readings. The MH is only on the middle. so if he continues to hold his meter at a 90 degree angle as he moves to the side he will cut out more light from the sensor the farther he moves of the center axis, and the same thing would be true for one florescent mounted in the middle of the tank.

so just like the old 150DE vs 400SE tests they are using the reflectors and the position of the sensor to give them the results they want instead of making it a proper comparison.

I think the very first post in that thread is the one which is the most creditable.


08-10-2007, 11:14 PM
Yeah, but comparing a 250W MH bulb to a single 39W T5 bulb isn't the point, is it? It's comparing comparable output and their PAR values, no?

08-11-2007, 12:15 AM
Yeah, but comparing a 250W MH bulb to a single 39W T5 bulb isn't the point, is it? It's comparing comparable output and their PAR values, no?

nope, single bulb to single bulb is the only proper way to compare intensity, we are not talking about coverage or average PAR or total PAR over a tank, we need to look at what is important, PAR intensity at a single point and every time a MH will win that argument.


08-11-2007, 12:48 AM
nope, single bulb to single bulb is the only proper way to compare intensity, we are not talking about coverage or average PAR or total PAR over a tank, we need to look at what is important, PAR intensity at a single point and every time a MH will win that argument.


That doesn't make sense to me at all. Why is PAR intensity at a single point more important? Why isn't coverage and average PAR, or total PAR over a tank? It seems like a really biased way to test things, since MH is designed to be intense at a single point (relatively speaking).

It's also not practical for what we do. We don't want PAR at a single point. We want PAR throughout the aquarium. At least I do.

But back to original idea of T5 PAR and Bulb selection, PLEASE!! I have no desire to see this become a MH vs. T5 debacle.

08-11-2007, 03:48 AM
simple. intensity will tell you how far you can penetrate, if tests are done properly you will see that light has 1 constant for the amount it decreases in intensity for a distance traveled.

so by being able to compare intensity we can determine the depth we will have suitable lighting at.

the T5s do have a bonus and that is uniform coverage, but that is at a cost. less intensity. it is the same as VHO, PC, NO ect.. as I have stated before a PC is brighter and more intense than a NO T5 as a PC is actually a T4, but don't get confused with the smaller tube size being better. that holds true for a given wattage. so we would have to relay compare a high output T5 to a VHO. the T5 will be better than the VHO, but I would guess by only 15 to 20%. the big advantage is size which allows you to put more wattage under the hood and a more even lighting.

But even this comes with a cost, with florescent tubes the smaller the size with the same wattage the more intense and the more heat that is produced, fluorescents main enemy is heat and as a result really impacts bulb life. as we saw one poster int hat post stated that they shift more red in 3 months so you should change the bulbs that often. so 4 changes per year compared to 1.5 for VHO/PC and 1 to .75 for MH. Also if you set up your MH properly you will get an average 2x2 coverage that will give you bottom PAR values than T5 with no problem.

the main difference is that lets say you have 1 T5 tube in say 14" of water and it has a bottom value of say 100 (just to pick a number) you now add 10 more tubes under that hood and you bottom value is still 100, just more of the bottom has that value. so you have not increased your intensity at all by adding tubes only the coverage which is a good thing, don't get me wrong. but now if you take that same 2x 4 tank with two good reflector SE MH you will find you have a bottom par of say 400 or higher (in relation to the other number) over 70% of the bottom and say 200 to 400 in 20% and 100 in 10%. over all the MH will pump a way higher average but it will not be evenly spread which is good also as it alows you to mix very high light corals with ones that don't like so much.

now having said all this we had a guy grow some colored SPS under NO's granted he had them high up and the growth was slow but they did have colour. so any light can work, it just depends on your overall goal and the method you want to take to get there. but changing 500 watts of MH bulbs once a year is a heck of a lot cheaper than changing 500 watts of T5 bulbs twice a year.


08-11-2007, 04:51 AM

back when I had my 4x39W Teklight my bulb arrangement was this:

G-man actinic
Coralvue 10K
Coralvue 10K
G-man actinic+

The Coralvues are kinda crappy and yellow but I guess the got the job done and they're cheaper. G-man's are good bulbs and I think offset the yellow of the coralvues very well.

That Grimreefer's thread that you linked previously contains a wealth of information if you have the patience to sift through it.

I'm now using 3x175w MH w/PC actinics over my 6-footer. I plan on switching to an "overkill" setup using 250w HQI (XM 10K) with 2x80W T5HO (G-man actinic+) and 2x160W VHO (UVL super actinics) in the very near future. I hope to get the best of all worlds with this setup: the PAR and penetration of the 10K MH bulb, the blue spectrum of the T5 and the actinic pop of the VHO.

For the record, the had the T5 bulbs in the teklight for almost 18 months without changing them and I did not notice any noticeable degradation in light output/colour over that time and the corals (LPS/softies) did not seem to "sag" at any point.

08-11-2007, 04:20 PM
I've been running T5s for a while now on a few different setups. The best bulbs available to us in Canada are the ATI line up, they produce the highest par ratings that I have seen compared to other bulbs.

The most common bulbs used are the;
Aquablue special (around 14000K), if you like whiter tanks this bulb alone will produce the color you like.
Blue + (around 22000K), basically just a bright blue bulb, you can add a few of these to create a more blue tank, I believe a 50/50 mix of the blue+ and aquablue will create similar color as a 20K halide.

Also new from ATI are 2 new bulbs;
A Pure Actinic which has a pink/purple glow and acts much like a black light making corals glow, however I've found similar pure actinic bulbs to be drowned out by the much brighter other bulbs.
A new daylight, similar to the aquablue special but is said to have a 5% red spectrum just like the KZ coral light bulb. The extra red gives some more color pop from opposite colors like blue, purple and green.