I've got 9 BB G-Bombs in a 75x75x160 budbox under a 400w cooltube (MH then Dual Spectrum) and a 125mm Ruck Fan with a CF. I'm growing in organic soil and basically because the wet/dry cycles on the plants have drifted apart a bit the levels of humidity are at about 65% during the day and either the same or a little higher at night. i can fix the fluctuations between day and night with a heater (which i need anyway) but due to the large amount of damp soil and the fact that it's fairly cramped in there, i can't get the humidity down (even with fan at full power). Forgot to say... BIG issue... extracting/intaking same room...
Firstly, I'm thinking of covering the soil with a layer of clay pebbles when i start flowering but then i'm thinking about getting a dehumidifier as i can't really see where the moisture can go. i have a window open in the room to get some fresh air in but i'm thinking that because of the intake/extract i'm gonna need some sort of mechanical assistance. the other option is an ozone generator which apparently kil fungus. some people seem to think these are dangerous though so i just don't know.
I'm gonna start flowering next friday so any ideas would be welcome. it's all going well and the last thing i want is a fat dose of bodrot..... help!

I think your only options are a dehumidifier outside the tent in your room or if you could extract the air from your growtent outdoors that would be much better.
Is there no way you can extract the air into another room?

sadly not... only option would be to start knocking holes in walls... which really isn't an option. the room the tent is in is pretty small so i could just dehumidify the whole room but i don't really want to spend £100 on a dehumidifier... i will if i have to but i don't want to...

i was sort of wondering about hanging a mini dehumidifier in the tent (one of the argos ones) has anyone tried this?

Heya immoreorlessaliv... , humidity's pretty high country wide i personnely wouldn't go spending yet as the plants will be fine going a couple of weeks in altho dehumidifier is mind assuring and pretty much needed towards end of flower or more so for me anyhow for drying . when you get to no youre steup you can use cooler spaces in youre room and placement and by say tube heaters to , bits of black & white on top can also help even drying etc small incitements , big gains , ps intake ? and keep up the proper watering , good luck .
edit

sound... chrs TS... i'm not paniking yet but i like to get somthing in place before the event, as it were. i'm gonna invest in a bag of clay pebbles first and foremost but i have a feeling a dehumidifier might be on the shopping list. unfortunately, theres not much i can do about the wet/dry cycle. like you say there are different temps/airflows in different parts of the tent and i was shifting them but things are getting a bit tight so i'd rather just water them when they need it. they seem happy enough.
i'm just torn between either doing the whole of the room the tent is in with a full on dehumidifieder or trying a £45 argos one actually in the tent...

just found some bits of black'n'white... problem sorted... 45%... nice...