Good start?

Well first off, good work on reading some grow guides. Second all your links to lights don't work like you want. They just bring people to the lighting home page of homedepot. And yes 320 watts would be enough light for 3 plants.

You most likely won't have to worry about heating the grow room up as mj plants like the temps to be between 70-75 degrees F.

You shouldn't have to adjust the ph in your water too much, unless the source your using is naturally too acidic or base. A lot of people use rainwater. I use spring water that I have delivered to my house, but you can simply use tap water and leave it out for a day or two.(you might want to invest in a ph test strip kit if the water in your area is particularly harsh) If you do need to adjust the ph of your water then Yes your pool ph kit will do fine.

Odor is going to be a concern of yours with 3 plants producing a decent amount of bud. You could grow a strain that is low in odor. Or you can go many other routes. I see you can't vent and well that sucks. If you have one of those ionic air things they do wonders, if you don't just use a lot of air fresheners and candles.

Harvest weight depends on the strain, the conditions it was grown under, and how big you let it grow before you flower it so its hard to guess.

As far as seed suggestion goes, I would recommend nirvanas papaya strain. I grow a special cross of it and I grow some every crop. Big buds, big punch, quick growth, early maturing. Even if you didn't like smoke (which you will), the plant itself is great just to have for crosses. When I do grow regular papaya I normally harvest 2-3 oz per plant in soil dry weight. And I am sure a better grower then myself could get a higher weight.

Veg times, once again depending on what you do, normally only last for about a month. Flowering, depending on strain, takes 8-10 weeks, some strains can take even longer but they are very rare.
Hope this helps and good luck.

 

Let me know if you find Mylar at Home Depot. I checked mine and they didnt seem to have it. Good luck!

 

First don't worry if your temps aren't prefect the plant will grow fine in 80 degree weather. Its when the temps get 90+ that you will start to see signs of heat stress.

Cfls barely create any heat at all. In fact you can keep them about 1.5-3 inches away from the plant due to the low heat they put out. As far as 200 watts for 2 plants, yes I think you should be fine. The general rule of thumb is 50 watts of hid lighting per sq foot. Cfls are as effective but you have double the wattage so you should be just fine.

Most seeds are sold in 10 packs but you they can be any number, 12,15,20 etc. It will be very rare for a pack to have less then 10.

Your going to want some ventilation if only so that your plant gets fresh air. It makes a surprising difference in quality and quantity.

 

Heres the link to Nirvanas papaya strain that I love to grow. Gypsys the guy I got all my seeds from and I've never had a problem. Hell he might even give you a free pack of somthing esle when you order. And if you don't want nirvana seeds thats ok they got a long list of other companys. Hope this helps and happy growing.

 

Well I can't see the cabinet but you've seen one cabinet you've seen am all. While you may not need 200 watts of light in the veg cycle, it will make them grow bigger faster.

And yes carbon filters are very effective at getting rid of the odor. You should only need one filter and that should be on your exhaust.

I have never used a 250 watt hps myself but I would guess that you would want it around 6 inches away or so. To make sure place your hand on top of your plant, if its uncomfortable to keep it there then the light needs to be backed uped.

Yes the 1 to 2 weeks is the suggested veg time due to its quick growth. Yes they are all females. And I couldn't tell you about ak-48 as I have never grown it, its on my list to grow.

 

Yes unfortunately they are expensive, so if you can't afford it just try to mask it with air fresheners and burning candles.

Yes they say you need only veg the plant 1-2 weeks, normally done flowering in 7-8 weeks. And yes its normally one month for veg. I still veg my plants out to 1-1 1/2 months. The only thing that happens is I get really big plants, which I prefer as I don't have to grow as often(I only grow so my friends and I don't have to buy).

You mentioned before that you wanted a wide and low plant. Well papaya stays relatively short. I use LST or low stress training as well. This ensures they stay low and wide while providing more light to lower branch sites. Heres the link to vokals Lst method. Its probably the best instructions on how to lst I have ever read.

 

That looks like a great carbon filter system to make. I currently don't use a carbon filter system I just vent it through out my place, don't really care about the smell, so I couldn't tell you how often you would have to replace it. Although I don't think you will have any problems if you change the filter like you stated.

Don't worry about the ionic air purifier. Most people grow using a carbon filter to scrub the exhaust air and it eliminates the most/all odors from my understanding.

Your final set up looks great. If you can find a bigger box even better cause the more room you have to grow the more bud you can grow =). Excellent choice on the strain. Good producer and useful to have around if you ever decide to cross breed =). Its good to be cautious with ferts because a lot of people over do it and end up hurting the plant. Just remember that ferts are like food for a plant; too much and you'll make it sick and give it health problems: to little and it'll be a starved weaklin.
Good luck with the grow and when its done you have to post pictures.

 

Good buy on the light, the 250's are extremely verse tail and can be used a lot closer then the higher wattage ones.

Yeah I see why you’re leaning towards the smaller one. For a 60-dollar increase you don't much added space.

As far as your 250 having enough juice to cover the larger box, don't worry about it. The 250 should cover the box quite nicely, leaving only a few dark and dim spots. If you wanted to you could fix those spots with some warm white light cfls.

Single plants vary in size. Some people grow ungodly large plants and take months vegging them, others grow am small and fast. You should be able to fit 3 ten-inch square pots in there. While it doesn't seem like much it should provide you with enough soil to produce a good size harvest.