MARS HYDRO inline fan and carbon filter kit

Was going to go AC infinity for their basic cheapest fan and filter (UK) but on looking saw the mars hydro alternative to be a third cheaper so snapped it up.

I looked at the few (not many) reviews and all said it was sound… well a little louder than the AC infinity but on par otherwise.

The kit I got was this - 4 Inch Inline Fan And Carbon Filter - Mars Hydro UK Official
The bottom of the range stuff but speed controller being what I wanted the most as presently downsizing from a high power ruck six inch on a Variac five speed which after ten years still works like the day it was bought. Unfortunately it creates too much air and wind in smaller tents even on the lowest setting.

I’m guess I’m just wondering if it’s a good piece of kit even comparable in most ways to it’s competitors since I opted not to get the AC infinity kit for £60 more.

The rest other than the hook up like hanging ropes, ducting & clamps I’ll probably bin as no use for them.

I’m mainly going to be using it at low speeds just to exchange air not implode my tent hopefully looking at the videos

Are these just new or not worth getting, I didn’t see much on searching about.

:grimacing::grin: Thanks :cold_face::disguised_face:


It will work fine. I do cheap fans. Expensive lights.


Yer I couldn’t find any issues, I get it today if the delivery driver doesn’t mess up or like ring the bell and drive of in the time I’ve answered the door.



Should work fine , If the fan is a little louder than you like, you can always install a peal an stick sound deader kit on the outside housing. Good luck :v:


Some noise is fine, thanks


Got it and setup -

Pros -

Works well
Moves air well
Easy to set and use

Cons -

A little too much noise on full
The lowest speed setting leaves blades motionless
The old ruck rock on a speed controller felt more professional and not as flimsy

Leaves me thinking the AC infinity fans aren’t that great also but the blades of the mars hydro aren’t exactly top notch designs.

Overall I’d go for a ruck rvk type can fan as better quality less noise more optimal design and don’t see the mars or AC outlasting one.

Overall feeling - quite happy, haven’t run the carbon filter but looks bulk standard should do the job.


Some pics, easy to hang with a few hooks, the black ones came with it and silver are mine.

Speed controller the cheap version just a turn style knob can see hanging down. This is on a wire so can attach elsewhere. If you pull it out fan resets to max. Feels like it jumps speed when turned not that smooth but probably ten presets not fully variable.

Max speed is a touch loud, you could oversize to the six run it lower for less noise. Four inch inlines are notorious for being a little loud at max. Probably running it speed two just a hundred watts over a few seedlings so no need for much heat removal.

Nice the carbon filter has hanging attachments in the form of small hooks. Easy to hang when flowering comes around. Filter was free of carbon, tend to have a light dusting on most I’ve had before like Rhino to name one. Seems good quality can test it for smell yet unfortunately.

Price was the main buying reason, seems worth it compared to the AC infinity. One issue the better fans and digital controllers especially temp and humidity shoot the prices if all up significantly. This whole kit with loads of extras just over £100 or $130 us although I’m UK probably cheaper stateside.

Long term see if the fan bearings last or start to wear and produce noise after a time, feel like the quality of these is lacking these days.

Found a pair of glasses not advertised on the kit stuffed in the ducting, AHH it’s something I might try but again not needed but nice touch.

MARS HYDRO Score - 7 out of 10 could be better quality but certainly does the job in a budget.



You shouldnt need full blast. A little negative pressure and a fan iside for movement all ya need.

I have the Mars Hydro 6" pulling from my 3x3½ closet. The fan/filter are in an adjacent closet, the kind with sliding glass doors so noise easily escapes, and it’s still relatively quiet in the room. It works really well too, and the dimmer knob being on a cord instead of attached to it is really convenient.


I had a in-line 4” in my 4x8 grow tent but it wasn’t big enough to keep the temp down so I purchased a 8” ac infinity. I hung mine but it does restrict how high I can raise my light. I have however seen where fellow growers set them on the floor, in a corner of the tent and it appears to save room. Next grow I’m going to do the same. I agree they are pricey and cheaper brands work just fine. Good luck with your grow.


That’s how mine is. Just be sure you hook up to one of the upper most ports of the tent, and not the bottom. That way, hot air keeps moving up and out, and not pulling down.

1 Like

Thanks I appreciate that info

1 Like

It could be a little too close to intake for best effects but yes people do although I’m gonna say it’s not optimal.

Some reverse setup and have filter outside of tent fan blowing again not ideal.