T5 and SPS observation

[shred5]

One thing is halide is point source and t-5 is not and we need a different way of thinking.. Take my 40 breeder and I had one 250 halide over it. My corals off to the side of the halide always ended up growing more on one side and the corals actually bent toward the light.

Now you change that halide out with t-5 and take a coral to the left of the halide which received more light on the right side of the coral. You make sure it is getting the same par as it was getting with the halide. But is it really? Now it is getting light on the front side from the lamp in front of it, it is getting light on the backside from the light behind it and it is getting light on top and left and right. That could equal a lot more par overall for the coral. Same thing for a coral right under a halide which gets mainly light from above. Are we actually giving the coral more light so there is less zooxanthellae making them more pale? Yes I know a coral is getting light from the other sides also with halide but it is less and yes a better reflector like a luminarc can help a lot. The thing is, most people with t-5 buy good fixtures because other than elcheapos that is all there is. Halides there are crap medium and good and how many people actually buy the good reflectors.


I think one of the issues is people underestimate the par that comes from a t-5. We were trained over the years to think halides put out way more light than a fluorescent and they did. Now that gap is closer. Also the fact that so little light is wasted with t-5 and they do not look as bright because the light is not bouncing all over the place people think they are dimmer because the light is not hitting their eyes. When I had my halide it lit up the hole room and walls especially around the tank, my t-5 does not. All that light bouncing around the room was wasted but if you put a par meter right under the lamp wow.


We also can not compare par between halides and t-5’s one bulb at a time because with t-5 we use more bulbs at less wattage. A halide is point source and all the light comes from a tiny area where a t-5 the light comes from the whole length of the bulb. You have to figure it out by area because there is just now way to measure par with a t-5 unless it is done by area at a certain distance away. . A standard needs to be set for the measurement of par with a t-5 vs halide. You need to map out an area and average the par.

I think the pastel color thing is over blown. How many people have had brown corals under halides? There are always going to be corals that are different. We are keeping corals from all depths in the ocean in tanks that in most case are around 2 feet in depth. Some corals are going to act different. A deep water acro isn’t used to being 13 inches from its light source. A shallow water coral that bakes in the sun at low tide aint used to the lower light. Every coral is different and is going to react different. I have had very little in the way of pastel colors in my tanks but yes I have had it. For me it only seems to be corals with green in them. I recently moved one deeper in the tank and it seems to be getting darker. Now it sits about 7 inches lower but is that enough to make a huge difference? The thing is with halides we had more to play with because it was point source and did not have such uniform par as the t-5. If a coral was not doing good we could just move it from under the lamp to the side or vise versa. Also a t-5 does put out more par in the middle than at the ends but it is not as drastic of a change.

Remember if a coral is light in color it has less zooxanthellae and what would cause this?. The coral needs less of it to get its needs fulfilled. What are those needs? Food and oxygen. What cause algae to produce more glucose for a coral or more oxygen? The answer is more light. It could also be because it is getting those needs somewhere else like food in the water column. So I doubt more food is the right idea unless we have so little nutrients the zooxanthellae can not survive and are not getting their nutrients but then I would think we would also see this with other types of lighting .

Just some ides any way. I could be way off base but I think it is a start.

And I want to add this so the halide people do not come in here and start bashing t-5 . I am in no way bashing halides they work well and with a good reflector are awsum. Each has its advantages. These are two comparable lighting sources with two different techonoligies. You can not test them the same way you tested the different halide bulbs.
Dave