White paint is good, dont spend mony on mylar, beter by a good reflector hood or beter 2 more 400hps lamps.
You can buy a good carbon filter for 50 usd (for youre setup)), why would you conssider DIY? Have in mind that a 8" in line gets pretty loud, if not autenated.In my opinion you only need...
In suouth Cali. U can do 3 rounds in a season with auto strains, if U start early. Autoflowers are not fotosensitive, they need about 6-8hours of direct sunlight,daylight hours are not very important (imho), but hot temperature results in shorter plants and lower yields. Longer days only resolt...
In that dim. tent a 1 600w HPS will not be sufficient.U need at least 2 600 HPS for that space.If U plan on putting tubes, than U should consider even more than 2*600 HPS.
Than U can put 2x 6-9 auto flowers (biger strains 100-120cm).Smaller strains U can put more, 2x 20-30 auto plants.
In my opinion this plant is owerwatered, this ollsaw couses the nutrient def.The plant could olsow use more-beter light.First you must set up the grow-room, then you bring in the plants.Before that do yore homework and read some indoor grow manual or beter a book.
Without basics your grow will...
If you live on sunny side of the Alps (Europe)for outdoor, autoflowering strains are a blessing.
And since cloning of autos is ollmost imposible, the seed companys have a big interest in making autos beter, than regulars. I think they will invest allot into autos in next years.
I have heard about something like this thing too.This is an old recepie, on how to make a killer grass with poison.I had a prevelige to smoke it, and it was not nice.Strong and ollmost painfull stone accompanied with most uncomfortable feeling.I,m not shure with what kind of substance-poison it...