I have a 400 watt mh running and a 600 watt hps running and I just switched to 12/12 about two weeks ago. All of the plants seem to be the same size. Will I get decent buds with the 400 watt MH?
Id stick with the HPS, or a mixture of both, just takes some time after switching for them to adjust. To answer your question, you can, but it isnt ideal by itself.
The 600 watt has a brand new hps bulb in and the 400 watt has a brand new mh bulb in....I have a 400 watt hps bulb but it has been used through three grows. Used 400 watt bulb our brand new mh bulb?
Ok so you have 600w Hps 400w MH If your in flowering its best to use Hps Bulbs so if you can put an Hps bulb in the 400w then you should. Useing MH and Hps at the same time is fine but Hps is better.
True, but you'll get great fat frosty buds using both a 600 watt hps & 400 watt mh (great choice by the way, gives out the full spectrum or dual spectrum, whatever you prefer to call it) using only an mh during flowering will give you airey frosty buds covered with resin, but with an hps you get fatter but less frosty,resinous buds but still sound & will get higher yield with hps than mh................now using both in conjunction will produce big fat, frosty,resinous buds & good yields comparible to using just hps lights but better quality smoke.....can guarantee you that hope this helps ps; use your bulbs for a year mate they last around 20000 hours before losing their effects, i change mine every year...