Help Help Glaciation clogging my vents!

OK so I vent out the fireplace and its COLD and getting glaciation and the flow of air is not as good as when it was warmer out.

Should I...

A. Run my fan on full time on low
B. keep my fan on 30 min cycles on low
C . Run my fan full time on full/med
D. Run my fan on Full on a 30min timer
E. other

I'm thinking maybe on med/high full time to melt it off maybe of maybe that will make more ice ..???

how high is the humidity in the air your pushing. maybe find a way to remove the moisture before venting. possibly a plenum (a metal box basically) with a dehumidifier in between your grow room and the fireplace. ice will destroy brick if thats what it is constructed of.

Only a thought but if you used insulated ducting maybe it would keep the air warm until it actually hits the chimney then it may rise straight out of chimney before it starts to cool and cause the waters in the air to freeze.

Turning your fan up more may help as well as it might force the air out quicker, you could always attach a dimmer switch onto the mains wire for the fan and then turn it up bit by bit to see how it goes.

its a metal fireplace, no brick for it's internal workings. I think it's going to be ok but it was hella cold yesterday. I kept it on the 30min timer and just put the fan speed up to medium I took my humidity down to 17% for about a day and it melted off the excess ice. But now it's slowly building back up because I have to turn the humidity up for my ladies. Thanks for the replies. if I have time or the weather stays bad I'll contemplate the dehumidification chamber.