If your looking for purple buds this is not the answer.
Only 3-4% of people that use this even see color change. This is even verified by the company.
This product was originaly sold under the name "Stacker" I belive. It is supposed to stack the budding sites closer together.
If you want purple plants. Use a purple strain. You can also expose your plants to colder atmosphere which will most likey stunt growth and end up with stems turning purple. Buds will probobly stay the same.
Dont waste your money.