I just finished reading through this thread and I want to thank you Hoppy and all those that have contributed. Now, if only I can wrap my mind around this and make sense of it I'd be well on my way
My tank is 48" x 18" x 24". Right now I have two 48" T8 bulbs that say nothing on them other than they are 40 watts each. They are pink and came with the tank (bought off craigslist). I also have two 36" T5 bulbs on the front side of the tank. Both are 39 watts one being 6500K and the other 10000K. I have no clue the PAR rating of any of them. I am concidering just starting over with new lights all together choosing something from the charts you have provided so the PAR is already pointed out for me. I do not use Co2 and don't plan to start. So, I definetely need to stick with low light.
If anyone of you reading this have a tank similar to mine without Co2, and your plants are doing great, please share with me what you are using. Hoppy, if you have a recommendation, I'd greatly appreciate it!
Thank you for your time and effort you've put into this thread and helping those of us that are at a loss in the lighting side of the hobby.