I did look at that and while I do appreciated the help, I do not understand chart chart at all.
I simply would liked to hang two PAR38 6500K bulbs from pendants above my rimless 40gal tank 37x15x18 and I just need to know how high.
Go for it. Hang them temporarily and raise them until the tank is lit the way you want it to be. That might be lighting most of the bottom or lighting all of it with some spill though the glass unto the floor.
They make really nice cichlid tank lighting.
I'm sure from an enters standpoint all this is great info. But, I think a lot of it is lost on most of the readers.
Yes, but if you read enough of the posts, long enough, the info starts to make sense. After a while you'll be one of the gurus posting info.
Please let us know, with pictures, how your two pendants work out.