Need advice on filter upgrade

Hi all. I have a couple questions about upgrading my carbon filter system. This last filter lasted barely 9 months, and now I can smell my dry tent that is ducted in! Not ideal. I also have always had issues for the last 1-3 hours before lights out where the filter just stops working.

First the setup, then the questions.

4x8 running an 8" ac infinity with an 8" xl filter. 6" intake fan with a hepa filter box and a merv 8 filter. I have a length of 8" ducting from my 5x5 dry tent into the big one as well (this has been working completely fine until this week.)

I only run the fan at speed 5 max for sound as my 1959 ranch's floors have 0 insulation.

I am thinking about upgrading the size of the filter and using a reducer. A., can I use a reducer? Would a 10x39 Phat rated 1400cfm work best? Is a 12x39 (1800cfm) reduced to 8" still work with the fan running at ~400cfm? I also have a silencer I could throw in there. I would also probably prefer to put it back outside of the tent which would add another 90° curve or two.

Thoughts? Your advice is appreciated in advance!

All my filters are oversized, with reducers

Go for the biggest, as long as your not sacrificing quality to do so.

Also use acoustic duct if you don't already, for the sound

coreywebster said:

All my filters are oversized, with reducers

Go for the biggest, as long as your not sacrificing quality to do so.

Also use acoustic duct if you don't already, for the sound

Click to expand...

Huh, I forgot about that stuff, thanks for the suggestion!

What's the OD vs. ID? My 8" aluminum ducting is super tight in The 8" holes if my tent, there's no room for insulation

I have an oversized can filter in a 4x8, running approx 3 ft of duct to a prime evo 6” inline on lowest power, then another 6 ft of duct exiting the tent.

The filter is going on year two of keeping odors controlled.

My personal opinion is that the brand and size of the filter is the most important component next to having negative pressure in your tent.

nygaff1 said:

Huh, I forgot about that stuff, thanks for the suggestion!

What's the OD vs. ID? My 8" aluminum ducting is super tight in The 8" holes if my tent, there's no room for insulation

Click to expand...

Run the insulation up to the hole and seal with some form of tape.

You can place fan out of ten with the reducer on the inside and connect to thatthose reducers are actually quite long so its not like the od will make a difference since the duct wont pass through the hole just the reducer

nygaff1 said:

Huh, I forgot about that stuff, thanks for the suggestion!

What's the OD vs. ID? My 8" aluminum ducting is super tight in The 8" holes if my tent, there's no room for insulation

Click to expand...

It's about an extra inch on the modern black stuff , an extra 2 inch on the foil stuff.

But it squashes.

Makes a big difference on air flow noise, not so much if the issue is fan hum.

SteakBags said:

I have an oversized can filter in a 4x8, running approx 3 ft of duct to a prime evo 6” inline on lowest power, then another 6 ft of duct exiting the tent.

The filter is going on year two of keeping odors controlled.

My personal opinion is that the brand and size of the filter is the most important component next to having negative pressure in your tent.

Click to expand...

I'm not familiar with that brand of fan. What's the cfm you are pulling? I also rely on the fan for humidity control during parts of the year, so I can't just set it to 200cfm and call it a day.

That being said, what does everyone recommend? Can 100? Can-lite 8x39? 10x39? Phresh 8x39?

nygaff1 said:

I'm not familiar with that brand of fan. What's the cfm you are pulling? I also rely on the fan for humidity control during parts of the year, so I can't just set it to 200cfm and call it a day.

That being said, what does everyone recommend? Can 100? Can-lite 8x39? 10x39? Phresh 8x39?

Click to expand...

410cfm I believe. The filter is a can 66 with an adapter to bring the outlet to 6”.

SteakBags said:

410cfm I believe. The filter is a can 66 with an adapter to bring the outlet to 6”.

Click to expand...

Gotcha. I end up running the same cfm on my AC Infinity 8" on half speed, which I do for sound purposes. The difference between full and half speed is the difference between a soft whisper and a jet engine.