First Time Grow. Any Tips For Increasing Yield Would Be Awesome.

I'm currently using a DWC to grow Himalayan gold, Purple high, white widow and a clone called Mr. Bubba?? Anyhow, this is a medicinal grow and is approximately 2 weeks underway from seeds (with the exception of the clone Mr. Bubba which it has been 4 weeks.). I'm using some cheap 3 part nutrient powder called vita grow or something like that, epsom salt and dutch brothers Zone root conditioner. The plants are all at 900-1100 ppm except the clone which is at 1300ppm. The pH is at about 6.2 or so. I'm using a 400w MH bulb in a 48x48x76" mylar coated grow tent temps at about 77.6F on average. I'm not trying to do anything crazy here that involves me buying anything expensive I'm only doing this as an indoor hobby, and would love to benefit from the time invested. Any information that could help me out by increasing yield and overall quality would be greatly appreciated. I will also be doing a journal, so check it out if you would like.

Thank you for your time and tips,

Ekho

I would strongly advise you to not use epsom salts. Bubbles, bubbles, and more bubbles. At min. you should have 1 watt of air pump per gallon of water. There is a such thing as to many bubbles but as long as it is not breaking roots the more the better. You can get away with a small air pump while in veg but once you get into flowering they will wilt if they do not have enough oxygen
your ppm does not need to be that high. for veg I personally dont go over 600 and for flowering I dont go over 1000. I dont think it is needed plus you risk burning your plants.

Just my 2 cents. lookin good man.

I saw on myth busters that playing death metal too your plants help alot. I played As I lay Dying 24/7 basically and they were bigger then they others and way more fucking stony. deathmetal is the shit

So do you think I should lower my ppm when I do my next reservoir change, or just keep it where it is until flowering? Also, what do you think a good age/height would be to start flowering?