LordeVolde

<span class="link_user">@Psilocubensis</span>, Heres a pic of the top - https://ibb.co/sw1fGq2 - I use that carbon pre-filter on my intake ports at the bottom as well, keeps bugs and shit out lol.

<span class="link_user">@Psilocubensis</span> so yeah theres actually a hole in the top for the exhaust about 20&quot;x4&quot; you can kinda see through there, Ill take a pic of the top later tonight - the fans do blow left to right - as well I ended up adding a 1/4 section of 6&quot; PVC to replace that 45 degree board, which helps with making the change of airflow direction smoother. Like I said though, for the cost, id seriously consider using a good inline fan. As for noise anything below about 95% PWM is essentially silent to me, as I have a lot of other fans in this room lol. At 100% PWM it creates a bit of a low rumble Id say? Not sure how to describe it, but its not &quot;fan whine&quot;

<span class="link_user">@Psilocubensis</span>, Yeah the two filters are just &quot;Hydro&quot; brand 4&quot; carbon filters - I have no prior experience with the brand, but they have worked well in my setup. Here is a pic of the box they feed into - https://ibb.co/2svrWmr - as you can see the original setup was for a single filter, which wasnt enough airflow - I couldnt sacrifice ceiling space, so I went with 2x filters instead :) As well for the fans, I started with cheaper, more quiet server fans rated at 140mm/1250rpm/75cfm - thinking 3x of these would be plenty, with the carbon filter restriction it was far from it. Ive since moved to using the Noctua Industrial series (iPWM2000) - these are rated at something like 130cfm each at 100%pwm and are finally a fan up to the task. With these Im able to vary pwm to fairly adequately control humidity and air movement is sufficient that bottom-&gt;top temps are nearly equal with my ambient, which I basically had to have since this room struggles to stay under 78F during the day lol. To add to this, Ive recently experimented in a similar volume tent (a friends setup) with a 6&quot; filter and 6&quot; ac infinity fan. In restrospect, I would likely use this config, or still use 2x 4&quot; filters, and ductwork to use an inline fan. Its not that this setup performs better, its just that it essentially performs the same, for a lot less work - and the ac infinity fan gives what I needed from an inline fan that I couldnt find - an open collector tach output and pwm control for fan speed - so with a fairly simple circuit I was able to control the ac infinity fan with my pi-based software. Now Im just hoping they will release a T6 without the controller. Essentially from what Ive found you have to have the T series to have the hall sensor (tach) installed on the fan side? I need to get AC infinity to confirm this but thus far they havent really indicated they wanted to work with me lol.

<span class="link_user">@OGgrows</span>, Thanks man :) Seems to be the consensus, I also realize now I made a conversion error on the calmag ratio, so I know Ive been feeding it stronger than I anticipated, so it seems I need to back off that as well! (Someone mentioned theyd seen what looked like N burn even from it) Ill be keeping everyone updated how it progresses.