100%… I got the T4 recently for 3x3… I wish I had listened to this same advise…
T6 will make you happer. I do like the T4 for my tent and it’s good enough, but as mentioned wish I got the T6 because it’s near dead silent 
On the lower settings and will still pull more air then the T4 on higher settings, which is not loud, but also not dead quite…
I concure with @DougDawson you should seriously consider the T6 over the T4…
I have not looked into that @CADMAN , what does the new controller do different from the one that comes with it? I have a T4 and T6 but both had the included controller so I am curious if the new one has other features? Apparently I can like your post in 37 min 
The Controller 67 replaces the module on T series fans (EC motor). It allows you to set a minimum fan speed and have it ramp up depending on temp or humidity. I assumed that I received the “old” controller BUT after fact checking again, just now.
Controller 67 is the latest one available from 2020. It’s my bad for thinking 
otherwise.
Just removed my horribly wrong comment above as I was wrong lol 
I do have and recommend Controller 67 that should be in the box when you buy the fan.
No worries bro, just curious was all. Good to know I am not missing any features or I might be looking at the new controllers 
So much gear out there it’s hard to keep up with the changes sometimes.
Yes your correct, both will come with the Controller as long as that’s what someone purchased, as you can still buy both separately…
I usually look at the bottom of the items description to make sure of what comes in the box is listed.
That’s exactly how I got confused 
I’m also outta likes 
I had a brand new Vivosun fan die within a couple of weeks. They reimbursed me the purchase price, but the ordeal gave me no faith in their longevity so I won’t buy another from them. I installed a T6 last week. So far, so good!
First one blew up,I heard this noise part of the fan came through the ducting,
Never buy anything from that company again
I ran 6 inch infinity with filter on intake and exhaust, I am not impressed. The fan had trouble with pushing airflow so I bought two big filters to make it easier on the fan . After 5 months she locked up . These fans are only good for one filter and it needs to be a big one .
Oddly I have had no such issues however I only use one filter inside the tents and have had no reason to add a second one. What brand filters did you use? Both my T4 and T6 remove all the odors with no issues at all. I would think either you had a bad unit or you are using bad filers. That is my experience anyway. Also never heard anyone state the issues you have, you are the first person I have heard with a complaint about them. Don’t get me wrong, that does not mean you don’t have a valid issue, just that I have never heard anyone else with it and I know of a ton of people that use them.
I’m all but sold on the T6, but for long term users that pair it with the Infinity filter, how long does the filter generally serve you before you replace it? I’ve heard loads of positive feedback on the fans, but mixed reviews on their filters.
I have not tried their filters specifically but do hear great reviews on Phresh or Phat filters. They can last several grows as long as you use the pre filters. A big thing is to get a filter that has the same air flow as you can buy filters that do not have enough air flow for a particular fan.
Get these for the best ones
I recently purchased a T4, and within a few days, the fan would not pull through the AC infinity filter if I had the pre filter on. They sent me a new fan determining that the first one was defective.
Needless to say, by the time the new fan arrived, the filter was clogged up from running for a week with no pre filter on. They then sent me a replacement filter.
2 weeks in on the new fan and new filter and everything was running great, until I noticed my temps going up. The new filter is somehow clogged, but the pre filter is clean as a whistle.
The room it runs in is a constant 70% humidity, so Im not sure if the humidity could be the problem or what?
I have decided to just let it go, trash the AC infinity filter and go with a Phresh or Can.
All in all, I feel the company has great customer service, but the quality of their filters is lacking. The fan will have to tell over time.
I have two t6’s and they work great. Overall very quiet for the amount of air they’re pulling.
I paired them with Terrabloom 6"x24" filters.
What’s the life like on those filters? Have you had to replace yet?
Controller 67 also allows setting some simple programs (i.e., turn on/off based on time) via a relatively insecure Bluetooth connection to a smartphone app (no strict pairing) and allows some finer control over temp/humidity set points as well as export of temp/humidity data over time in a csv file.
I also confirmed with support that there is no way to set up complex programs (i.e., set fan to ‘on’ at speed 4 during lights out while setting fan to range from 0 to 5 during lights on based on temp/humidity).
In the release notes for the latest app update, there was a note “now compatible with Controller 67 & Controller 69”…though I don’t see a Controller 69 on their site. So maybe there’s another new controller coming?
I also found this morning that they are in development of a Cloudline LITE series. They have a description of them as being budget friendly package systems, but no release date or pricing.
Regarding their filters, I used one of the 4" filters on a 2x4 tent for about 1.5 years before they modified the design to allow swapping the ends to reverse air flow through them. It was great for the first run and ok for the 2nd run, but by the end of the 3rd run the air in the basement was starting to be a bit noticeably funky during mid-late flower, though it’s still ok to remove the odor from particularly smelly plants in veg. I’m currently in early flower with an 8" filter in a 5x5 tent so I’ll see how the newer generation of filters works soon enough.
I’ve only been using them for the beginning of veg but I’ve read at least a few rounds
They also have a “Controller 2 & Controller 8” in their ‘Cabinet Fan Systems’.
To me it looks like they are planning to replace the earlier controller with the 67 controller after they draw down stock.
Another interesting note was they didn’t change the tooling (that shows good management).
At some point I’m going to open up a controller to have a look at the possibility of adding a proper controller to it, breaking out functions like complex programming data logging etc.
Cheers
G
I’m excited to see what you do. I was expecting it to have more options like you were saying. Lights off & fan setting, lights on & fan setting. Will you use a raspi or Arduino or something? I’m a novice programmer. 