400mh and 400hps for flower ?

Been flowering for 9days under 400 hps
I was wondering if it would be any benefit in firing up the mh also?
Or would it stress the plants as they've been under the hps

having both would be awesome.. both spectrums plus twice the power.. and as long as heat isn't an issue, you will be better then fine.. the hps will give you bud size and the MH will complement the growth (keeping it shorter and overall health) and bring out more tric/resin...