High Humidity/Heat Question

Will an active intake lower my humidity or temps? It's been very hot and humid the past few weeks and I'm about 4 weeks into flower. I've thought about using a dehumidifier but they're very expensive and I've heard they put off a decent amount of heat. My temps have been around 81-85 and humidity has been between 65-70. I feel that both these numbers are too high for flowering and I'd like to find a way to lower them(especially the humidity) for the final few weeks. Also, although I haven't seen any mold the plants seem to be "sweating" constantly and have a semi-strange/bad smell that I can only pray isn't mold. But they aren't very big or dense yet so I'm hoping they are just going through changes in smell. I'm running a dwc setup with a 600w cooltube and a passive intake using a 340cfm inline fan with a carbon filter. All in a GL120(4'x4'x6'7") I was looking into purchasing an 8" ecoplus axial fan for an active intake but they state(647cfm) which would I think would create a positive intake and cause smell issues. Would this or a smaller intake fan be of any help or should I just continue using the passive intake? I can also use a portable air conditioner if I have no other option but I'd rather not due to electricity costs. Any suggestions are welcome.

i bought a 25 gallon dehumidifier at best buy for under $100 only a month ago, well worth the money. another fan would cost more, but being you have a funky smell going on you might need it for better ventilation. have you checked your roots for rot? if your plants are emitting a moldy smell then there's something going on.

first of all...welcome to Rollitup.org. Second of all Iam a HVAC technician and a grower on the side. In flowering I strive for 70 degrees and 30 % humidity. A fan will not help you. Technicaly speaking a fan is only a desplacement of air...it will not lower the temperature at all. you need to get a humidifier running and lower the humidity. in return, you will need to run the A\C , the air conditioning will dehumidifly so monitor them both to achieve the needed boundries.

Thanks for the replies. I checked the roots and they seem fine(pretty white) and no noticeable slime or anything. But the symptoms I've read about root rot make it sound like that might be the issue(if there is one). The PH has constantly been low (3.5-4.5) so I have been adding a small amount of ph up about twice a week to get it in the 5.0-6.0 range. But I've heard that root rot can cause acidity. Also the smell smells kind of like wet socks which is also a symptom I've read about root rot. Also I recently started foliar feeding a very small amount of snow storm ultra so I wonder if that could be the cause of the smell too. I'm going to stop the foliar feeding for a few days and see if the smell goes away. I'll probably end up using my portable air conditioner to drop the temps, do you think this will be adequate to lower the humidity as well? Btw I'm using the lucas formula, big bud, bud xl(just did the first small dose), and snow storm ultra(foliar only). Everything looks fantastic so far but the strange smell, temps, and humidity are making me worry as I approach the final few weeks.

Any other suggestions on what the problem could be? Or solutions to the heat and humidity? Has anyone used damprid or similar products? Also some of the pistils that have been close to my oscillating fan have turned brown and look sort of withered and damaged. Wind burn? Is this stressful or damaging to the plants or buds? Also is the constantly dropping ph bad? I have been frequently adding ph up to keep it above 5 but it continues to drop to 3.5-4.5. Sorry for all the questions this is my second grow I just don't want to lose it to something preventable. Thanks guys