A filter wouldn't require a boost from 30% to greater than 100%, so something else is going on or it's a duct fan that can't handle the slightest static pressure without huge drop in CFM. Doubling power should be more than enough to mitigate effect of the filter being added with a decent duct fan. If the ambient RH of the intake air is not conducive, exhausting won't do much. If not exhausting to a different area where the air doesn't comingle with where the air is taken in, moisture will simply build up over time and keep cycling back into tent etc. Whether or not exhausting is 'enough' depends on the details. Can't force a square peg through a round hole. The other point to take note of is that the plant will continue to produce more moisture per before it reaches a steady peak by mid flower -- when vegetative growth stops. So, there will be an increasing need to deal with more mositure up until that point. If already having an issue before flip, it's very likely be an even bigger problem 4-5 weeks down the road. What works early on may not be sufficient later on. You may or may not need a dehum. That depends on your typical weather and how the intake/exhuast is setup up, etc. I only grow in winter months for this reason. My dehum won't turn on until mid flower and it doesn't have to run hard because ambient RH with furnace on is 30%. By the time the plants are fully grown, it more than compensates. Humidification is much cheaper. Also, the lights and colder ambient temps in the winter work out to 75-77F, which ieliminates need for AC or heat. Growing at certain points in the calendar can greatly reduce costs. If you do buy a dehum, buy one larger than your need. They usually recommend based on square footage, so include entire area, not just the tent... the entire lung room is the baseline for how large you need to go. Also, how large is the canopy? If you intend to scale up, need a beefier dehum, too. If your seasonal weather regularly resutls in high RH, even more reason to buy bigger than you think is necessary. lots of maybes and ifs... work it out and make the best choice.