Has anyone ever taken PAR ratings on the bottom of tank with differnt bulbs? I know lower K bulbs put out a lot more PAR than higher K bulbs. I would assume a 10K would put much more PAR on the sand (20'+) than a 20K bulb would. Someone was trying to tell me a 20K bulb will put more PAR on the bottom of a tank over a 10K, and it just didn't make much sense to me. Is this the case or not? I realize the blue spectrum is the last to be filtered out, but I thought that really occured around 6 feet deep at least.