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T5 HO or traditional fluorescent fixtures and bulbs?

1112 Views 5 Replies 4 Participants Last post by  sandybottom
Is the hobby dying off? There seem like fewer and fewer choices.

Today's question: for 36" long aquarium, is it better to use the old standard fluoresent plant bulbs or the newer T5 HO bulbs. {the full spectrum led at about $300 are poor price value solution}.

My go to used to the All-glass but their 36" uses 24" bulbs. I don't know what advantages there
are to the T5HO for fresh water. For salt water, no brainer. But concerned since it's HO the fish will think it's too bright and hide all the time. The 36" dual bulb hoods are difficult to find. My 48's would stick out 6 inches and so that is unacceptable except for temporary emergency lighting.

I haven't found a lumen comparison and only discussion I have seen talks about how much brighter the fish are.
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I am at the very beginning in understanding light for aquatic plants, so any criticism is welcome.
First: lumens per square meter is a LUX and is a measure of light intensity as it is perceived by human eye. Plants are different. Plants don't need full spectrum of light for their photosynthesis. That's why we have PAR (photosynthetically active radiation) to measure what's important for plants. Further complicating things is that light travelling through water (quite different than air) is losing PAR faster as the distance from the source increases.
New T5HO lamps, are designed to emit more in the red (650-700 nm) and blue (440-490 nm) out of the entire spectrum (400-700 nm). Therefore , T5HO make better use of less light. T5HO fixtures uses reflectors to redirect wasted light into the water. Led light does not need reflectors or ballast, uses less watts and lasts longer than T5HO.
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