Originally Posted by BradSD
Was shopping for a new light fixture today and the only bulbs I could find with the fixtures are the 10,000k or more. Why no lights with 6500k? Will the high k hurt my plant growth? These were T5 HO light fixtures.
I would submit and I believe Byron would agree that T5HO over your 55 gallon without CO2 injection or daily EXCEL (liquid carbon source), that you will soon have a tank full of beautiful and various forms of algae.
The T5 bulbs would represent High lighting and thus CO2 would be the limiting factor with regards to plant growth.
With high light and limited CO2 as well as limited nutrients, algae are much quicker to respond to these conditions than plants are.
I would were it me,(and it ain't) look for twin tube fixture that accepts T8 bulbs in the 6500Kto 6700K range.
These bulbs are much easier to find at places like LOWES and would be better suited for NON CO2 planted tanks.
When you increase the lighting over a tank with plants,you must also increase the nutrients which are more in demand, but more nutrients without CO2 also in higher demand,, then the plants will do poorly, and algae will thrive.
I recently set up a low tech ,low light, 80 gal planted tank with help from Byron and others ,and the tank is lit with 2x32 watt 6500k T8 bulbs and and once weekly dose of dry fertilizers along with Flourish comprehensive.
Plants are plants suited for low to medium or moderate light and growth is slow but steady.
CO2 and light are the driving factors in plant growth followed by nutrients available. One cannot increase one without the others and still achieve the balance needed to encourage plant growth and discourage algae.
I tried against all advice to the contrary ,to run 2x54 watt T5HO bulbs which produce considerably more light than T8's but were well within the often mentioned 1.5 to 2 watts per gallon for low tech tanks and the results were ...Plants faltered. there was not enough CO2 or nutrients to provide for the increased demand by the plants due to faster uptake rate that higher lighting presented.
I did begin to grow various forms of algae which pretty much was exactly what others said would happen but being somewhat bullheaded,,I had to see for myself. Seems I always learn the important things or the tings that stick with me,, the hard way.
Byron could prolly explain more in detail what I have attempted to, but I would hate to see you buy an expensive fixture and receive poor results. Hope some of this helps, I am still learning about the planted tank realm myself . And thus far,, I have learned that it is as difficult as I choose to make it.