Affordable washable intake filter for 4x4 grow tent

[DEVGRU_420]

Hey guys I was looking around for an affordable washable intake filter for my 4x4 grow tent. Should the filter below work? Should one work or do yall think I would need two, one on each side of the tent? Thanks!!
https://www.amazon.com/152mm-Intake-Replacement-Quality-Filter/dp/B07DS342Q6/ref=pd_sbs_1/135-8610649-9738401?pd_rd_w=KB72B&pf_rd_p= 0a3ad226-8a77-4898-9a99-63ffeb1aef90&pf_rd_r=78QP9114E ACSW277T8NX&pd_rd_r=f357f2c0-aa4a-4f32-be60-7a059c3d5b34&pd_rd_wg=GlGh8&pd _rd_i=B07DS342Q6&psc=1





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[f-e]

That's an engine intake filter. What you want, is something like wadding. To cover the mesh vents. Filtering the inlet air. Something that will stop mold, ideally.

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Merv, MPR, TO and FPR are just four of the many filter measuring standards.

As filters get better, they get harder for fans to deal with. Most building systems are going to struggle with a merv 13, as they were not designed for it. HEPA grades are not on this chart. The lowest efficiency filter in the HEPA grading system, is equivalent to MERV 17

Using a HEPA grade is expensive and problematic. Especially in passive filters, such as at the flaps of a tent. There, the extractor is expected to pull the tent deep enough into negative pressure to make the filter work. Most of the fan choices pushed upon us, are not capable of doing the job.

The standard sizes are 24x24 in the US and 600x600 for the rest of the world. Half sizes such as 600x300 are equally as common. 600x150 less so. 300x150 is still standard sizing. Though not for whole buildings like the 600x600 and it's close ratio's. Large HVAC systems may have 16 of the 600x600 forming a filter wall. They don't make them bigger, as they would fold up. This makes it a very popular (cheap) size.

The car filter carries no filtration specification. In tests, some have been utterly crap. More interested in flow, than filtration. That's what sells car filters.

 

[tobedetermined]

As f-e says, the hit that airflow will take is the issue. Since my goal was only to stop big bugs and pet hair blowing in through my intake, I just use plastic screening on a piece of 8" duct - held on with an elastic band so I can remove it easily to clean.

 

[Three Berries]

If it were me I would make a air filter intake box. Then duct that to the tent. You could make it out of four or five filters. This should give enough surface area to use a high quilty filter andnot drop the air flow as would a single filter.

 

[Switcher56]

I use a HEPA filter.

 

[f-e]

If it were me I would make a air filter intake box. Then duct that to the tent. You could make it out of four or five filters. This should give enough surface area to use a high quilty filter andnot drop the air flow as would a single filter.

It's perhaps the only way to do it. Some fans would also be useful, so you still get some clean air supplied when you open the door.

600x600 is a cooker extraction canopy. An old one from a skip, or new one for 100$, can easily have a filter taped on. They contain a proper fan, that makes a lot of our kit look silly. Plus they have speed settings that are not reliant on dimming. It's literally changing the motor. We should see them used a lot more.

There is only so much you can do, if you intend to open the door and let the dirt from your clothes drift in. This is why HEPA grades are only used for proper clean room environments. Where positive pressure takes care of the little gaps that air can pass through. Places where you change clothes before entering, and contain their own tool boxes as nothing is taken in and out. This is how big legal grows work. Merv 8 scrubbed air, pressurising the grow space. So if the door opens, clean smelly air comes out. Nothing gets in. Except the bags of dirt you can't control. Which is why you can only do so much.

I have worked on all that stuff. Clean rooms within clean rooms. White suits and respirators.
As we want negative pressure for odour control, anything we do is just a gesture. We have to be aware that fitting better filters, means more air getting in through zips and gaps. I could fit a plank of wood, giving 100% filtration. Then all the air within the tent has had to come in somewhere else. I have zero filtration by blocking my filter. We need the highest flow possible, which is the minimum filter grade for the job. Or.. get a fan that can overcome the problem.

 

[Gry]

Went the route described by three berries and am working my way through a case of home ac filters that I replace each grow.
Works well combined with the speed control on the fan. Am fortunate that I do not need to run carbon filters- so that is not an
issue for me.

 

[flylowgethigh]

I have planned since I started to make an intake box that sits next to the tent/ It will be 12" x 12"x 3.5 ft. I will put in an AC infinity fan with manual speed controller, that sucks through the 3M 1900 10" x 20" x 1" filter. The fan will be mounted in the box with the 6" hose attached to the fan and going out the box into the tent. A 6" fan can be run at a low speed making it quieter. The exhaust fan and intake fan work together, balancing the tent pressure as you change settings.

 

[tobedetermined]

I inherited the ‘hay wire fix’ gene from my father, so I made an intake out of a suitable cardboard box, a cheap 2-spd 5” fan, and 2 x 8” metal duct elbows. I cut the box and built an easy labyrinth for indirect airflow and I sprayed the whole interior (included inside of duct) with matte black paint. The 2 elbows gave a nice big 90 bend into the tent vent. I have an 8” for exhaust – running on medium - that goes through a similar but smaller box exit. Nice negative pressure and no light gets in.

 

[f-e]

The fans here just help it along. I fitted some wire to stop the filter getting pulled in. The filter seems to of gone though.

It smoked alright?