pot size?

I have 3 bio diesel mass plants, they are going to be under a 600w hps in a 80cm x 80cm x 200cm tent, what is the best pot size for me? Atm the are still small and in 13cm pots

Forgot to mention they are auto's and they are in bio bizz all mix soil

All dependsd on long you plan on vegging them. I would say you could go with 3gal pots easy.
That 600 is gonna generate some serious heat in that small of a space, hope you got the cooling issues worked out.

Ok, 3 gal pots will be plenty big enough, and still give you a lil room to move them around if needed.

I have no choice on veg time as they are auto's and I am going for a cool tube, I may even settle for a 400w and get a few fans in there too, so far have 4" inline fan for intakee and 4" inline to pump air out with a carbon filter

I was posting same time, didn't see they were autos. You said two 4in fans, are they true inlines or are they like the duct booster fans.
If yu can keep temps in check i would go with the 600w

They are inlines but only cheap 1s, part of an ebay kit, may invest in a cooltube and go for the 600w tbh, I think if I get 400w I'll regret it

3g pots will be fine for autos. id say the 600w is more suited for that size of tent. definatly get a cool tube

3 gallon is perfect! You could do more but it wouldn't effect the plant too much

My one piece of advice on autos - go very very easy on the nutrients. The 4 strains I grew hated nutrients and would burn on reduced strength feeds - the only 2 they got. Screw autos. I grew over 20 of 4 different strains. Only 1 was worth a damn - Dinafem White Widow Auto. I can do on 12/12 from seed what autos do and get far better weed and yields. Good luck and I mean that. In fact the only reason I had autos was testing some for something good to grow outdoors here in AK since photos are a "no go" outdoors here.

The 400 would work well also with your space. But if you don't already have the light then oi would def go with the 600.Give you a lil room to expand later..
A cool tube or air-cooled hood is a must with an hid in that small of space though.

Thanks for the advice I'll go for 600 with cooltube and 2 4" fans, I'll use the 3 gallon pots too and I'll make sure I go easy on nutes, cheers people