Urrrrrmmm, not to sure what you mean, if we use 'passive' air flow then slight negative is preferred, the extractor fan creates negative pressure as it takes stagnant stale air out while 'sucking' fresh air in to create a cycle, to me personally unless it's sealed I would prefer negative so I 'know' it's pulling fresh air in, I wouldn't of thought this would be any different if you have a dehumidifier in the tent as well, you still want that 'fresh' air coming in, hope this helps happy growing 👍