We installed 2 LED bath fixtures. Modern Forms Shimmer, 32W each, single pole, that the specs list as dimmable with an ELV switch. The ordinary on/off light switch is fine. I tried a 150W Lutron dimmer and the LED light humms. The light fixture manufacturer recommended the Diva ELV300. I tried that one and the fixtures still humm. Any explanation as to why they are humming and what dimmer switch will work without the humm? Thanks.