Hi.
I use LED light for my plants.
I had a couple of T5HO but I dropped them because of excessive heat in my area.
A dimmer, depending on the type, could produce flickering or change of Kelvin.
A mixture of warm and cold light is generally recommended to produce a wider spectrum.
If you think the light is too strong, you can increase the distance from the plants, which also increases the coverage area.
ciao Nicola