At 150x150 the question shifts. On smaller tents the volume decides which fan you need; at this size the tent is rarely the constraint any more. What decides here is the space around it: how warm it gets, how much noise you can absorb, and whether this stays the only tent.
Four diameters fit, and they differ in what they cost you later
Ø 150 mm is enough for a tent on its own and gives you the widest fan choice. Ø 160 mm is the largest group here and has the most filters and ducting. Ø 200 mm is the most comfortable choice once both a filter and a silencer have to go on. Ø 250 mm belongs to a warm room or several tents on one extraction. Pick one and hold it along the whole run.
Why a filter pushes you up a size
A carbon filter costs static pressure, and at this volume that weighs more than on a small tent. Add a silencer as well and a fan that delivers exactly enough on paper does not in practice. A generous size turned down runs quieter, draws less and keeps something in hand for when the filter loads up.
This is where the range stops
Nothing above Ø250 is stocked, and the largest carbon filter also connects at Ø250. If you have an existing system that is larger, the reducer to 250 mm is how you get a filter onto it.
Do not forget the air inside the tent
Over this floor area, extraction alone is not enough. Without circulation a still, humid layer sits against the leaf and the temperature climbs at the top of the tent, which is exactly where it can least afford to. Plan for movement above and below the canopy rather than one fan blowing at a wall.
Frequently asked questions
Which diameter for a 150x150?
Ø150 or Ø160 if the tent stands on its own, Ø200 once a filter and a silencer go on or the room runs warm. Ø250 only for several tents on one system.
Can I run two tents on one extraction?
You can, with a Y-piece, and it saves a filter and a silencer. You give up the ability to control each tent separately, so weigh that against the saving.
Why is there so much in Ø160?
Because filters, ducting and couplers are at their widest there. The fan choice is narrower, but it covers every type.
