150 watt hps stealth ideas?

How's it going, i recently purchased a 150 watt hydrofarm mini sunburst hps light. i am interested in doing a small grow, with maybe 3 or 4 small, fast flowering indica plants. i recently recieved a papaya seed, a blue mystic seed, and a northern lights seed, all from the single seed center.
i was thinking of doing 1 soil, 1 hempy bucket and 1 dwc
how small and stealth of a grow box could i have, without overheating my plants from the light?
i was thinking of a 2.5x2.5 footprint, with a frame that 3 feet tall and holds the light.
i was thinking to then wrap the box in a mylar space blanket and use a desk fan or 2 for ventilation. this is my second grow.
thanks!

I think for the sake of simplicity and space I'd choose one medium for all plants. 3 feet tall is really short unless you plan to scrog. The 150 is going to take about 14" for itself, the hanger, and roughly 8 inches from the plants. Add another say 6 inches for your pots or w/e and your down 20 inches from the start. Leaves you 16 inches of plant, including stem. I'd be flowering from clone or seed with that. My cab is cooled by a 50 cfm bathroom fan which is about the minimum for my environment to keep the temps around 80. The fan is not quiet by any means either so hardly stealthy in my book. I'd look into a quieter fan for my next cab.

I have a 150W HPS and some CFL's but I have like 1,7 m height in cab, so there is a space for heat to raise. But I think height isn't an issue if you put powerful exhaust and quite good intake. Just make some temp tests. Run them for 6 hours or even whole 12 or 18 and check the temp.

i've been running for like 3 days. i planted 3 seeds and they are doing well. one sprouted so far. i have northern lights, papaya and blue mystic. i plan to scrog them. you can follow the whole grow here:
[h=1]150 watt hps scrog-blue mystic, papaya, and northern lights![/h][h=1][/h]

oh and as far as temps, its a steady 78... is that okay?

Yeah thats a great temp

rad! do you have any experience with miracle grow organic soil? i planted my seeds in it, but after talking to everyone, i regret it. is there anything i can like add to the soil or what can i do?

If its already in it just don't add any nutes for a long while. Wait till you see some yellowing, which may take a month or 2. If youre using small cups to start, which id recommend, you can use some different soil when you transplant. I'm using a cheap $5 soil with nutes "already added" as well. I think the #1 plant problem has to be over fertilizing.

alright, that eases my mind. i thought they just weren't gonna grow at all. thanks man! good luck with your grow!