My second hydro run - 2 site RDWC in a 2x4... with an external reservoir!

mine seems to work ok outside the tent

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Thanks a ton for all the helpful input! One of the reasons why I love this community :smiley:

RE: negative pressure-- I dont / haven’t see any signs of this, so perhaps a non-issue. The house isn’t super duper air tight which maybe actually a good thing in this context haha. I’ll certainly keep this in mind!

RE: attic temp/humidity, this is definitely a valid concern and something I’ll be mindful of, I appreciate you looking out here. As a fallback plan, I can route the exhaust out of my office window. Fortunately for me, HVAC ducting is my favorite type of decoration :laughing:

RE: fan size – I think you’re right about it being undersized… damn! I ran the tent overnight and it struggled to keep temps much below 80F in the tent, despite the temp in my office averaging around 67F and the lights only on setting “4” out of 10. So, seems like a bigger fan is needed to adequately exhange the air in an impactful way, especially later on when light intensity will be higher.

RE: fan speed – noted! I set the fan minimum speed to 1 with the lights on. Hoping that little humidifier can keep up!

Great points Bamarayne! I appreciate the input. I am going to pull the proverbial trigger on a Cloudline Pro S6 today to replace the S4 that’s in there now :smiley:

My office acting as a lung room is indeed intentional. I have a draft blocker on the door to try to “isolate” the room from the rest of the 2nd floor, so I can e.g., crack the window (we’re entering winter) if I need to lower the temp in there. We run a whole-house humidifier on the first floor but it barely keeps that floor around 50% RH, 2nd floor is usually 40% in the winter which should be great for flowering. My last run I was flowering at the hottest and most humid part of the year which was difficult to manage. I’m deliberately doing this run in the colder months to benefit from naturally cooler and drier air, particularly during flowering.

RE: attic duct, yeah I agree with your reasoning here, particularly warming the attic in the winter should effectively act like better insulation for the 2nd floor of our home. I am slightly concerned about the added humidity, but unsure how to validate that aside from crawling up there and looking for signs of mold/mositure :grimacing:

This is precisely my concern and why I’m considering some HVAC decorations in my office to route the exhaust out of the window instead of the attic. I’m close to the Canadian border so “northern colder months” is very fitting haha.

Thanks for sharing that photo man! I’ll definitely give this a try before I go about trying to vent outside the house. How does the filter do with smell elimination in that room? Odor in my office is not a problem, I just don’t want to stink up the whole 2nd floor of my house. Our nursery room is adjacent to the office and definitely don’t want to stink it up in there lol.

Thanks to all the awesome community input – ILGM is the best!

I’ll update with changes when I can! Thanks everyone!


For your temp issues, that closet is working against you. You have to manually exhaust all the heat, since none of it can really radiate off the walls and ceiling inside the closet. It’s probably minimal, but it all adds up.

If you could get a 4" to work, one incognito option that I’ve done in the past is to use a 4" Y connector from the big box hardware store in the (woodworking) dust collection area, and splice into a bath or range exhaust in the attic. They usually have backdraft flappers in them already, so it all goes outside.

Dude, that is an absolutely amazing setup. You’ve done some serious work on that. I’m gonna have to hire you to redo mine next grow! :smiley:

:dash: :dash: :point_right:

With led lights you’re going to want to keep lights on temps around 80f or so. But also want to be able to hit full power on lights.

Hey thanks for the idea! I had a similar idea (tee’ing into a duct) when I was intending to run my tent in the basement. Obviously I didn’t follow through on that which I think would be good in some ways, bad in others, but I’m confident I can make this location work!

Wow that’s quite the compliment, thanks a ton Jim! I’m definitely excited to put it to use and hopefully the results end up being a positive reflection of the work I’ve put into this setup!

Hmm ok, interesting! Right now I’m testing out settings for veg with a leaf VPD target of 0.8kPa. I’m assuming a 5F leaf offset (have yet to measure cause, no plants yet!) which has me around 78F/60%RH lights on, dropping to 68F/50% RH lights off. I ran the tent for a couple of 24 hour cycles and averaged 0.85kPa (right where I wanted to be) with slight upward deviations which to my understanding is ideal for veg.

RE: light intensity - thanks for this input! It spurred me to learn more and do some experimenting.

I started by referencing the PAR chart from the light vendor (which I assume is at setting “10”, but I shot them this question to be sure), at 18" hanging distance the lowest PPFD reading (the corners) is in the low 400’s but climbs to 800’s and 900’s in the central region, with the higest reading of nearly 1200 PPFD dead center. My (limited) understanding of PPFD is that I’m looking for 250-600 in veg, and all the way up to 1000 PPFD in bloom.

I downloaded a PPFD app on my smartphone (“Photone”) and took a couple measurements at each grow site in preparation of the veg stage. At setting “5” my readings were low-mid 200s. I cranked the light up to setting “10” and readings jumped to the mid 400’s / low 500’s.

Question Understanding the higher setting will create more heat, if this becomes a problem (I dont think /hope it wont with the 6" fan now!), would my recourse be lowering the light setting (less heat) and moving it closer to the canopy until PPFD readings are where I want them to be? As a follow up, if I can achieve desired PPFD readings at a lower intensity setting by hanging the light closer to the plant/canopy, is there a downside to doing this versus using a higher intensity setting with the light positioned further away?

Thanks ILGM :slight_smile:

RE: Fan/Equipment input – My Cloudline S6, new charcoal filter and 6" ducting have all arrived so I’ll be installing those when I have a moment, then doing another atmospheric test run.

In other exciting news (for me at least :slight_smile: ) we are expecting our first born any day now (due date was the 11th :sweat_smile: ) so I’ll be MIA for a bit when she arrives as we figure out the whole “parenting” thing. Once the dust settles and the wave of family visits have come/gone, I’ll be cracking some seeds and getting this run started!

The temperature thing really just has to do with the leaf surface temp. Led lights don’t throw as much ir to heat leaves like an hps would, so takes a little higher air temperature to get to ideal leaf surface temp. If your vpd is corrected for this I think would be fine.

Turning your light down by dimming will decrease the amount of light output from your light. By definition your ppf per square meter won’t increase or decrease by raising or lowering your light, it will just change the pattern of light be being more narrow or wider. In the event you have you have a physically large light with a small plant under it what you’re describing will probably work. But this is not how this situation should be generalized.


AH! Thank you for this – this sentence alone really helped me understand PPF! Thanks :smiley:

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Has the stork landed yet?

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That is a negatory! Thanks for asking :smiley: We’re just playing the waiting game now. I guess she’s maybe a little stubborn, and if that’s the case she comes by it naturally :rofl:

She is setting the schedule now, kinda lets you know who is in charge. Keep us posted!

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Thanks @Ickey :slight_smile: We sure are excited to meet her!

Big news!! Our girl was born on Saturday and both her and Mom (and me for what it’s worth :stuck_out_tongue:) are doing great!! This week will be busy with settling in at home, visitors and the Thanksgiving holiday, but hoping next week things will settle down and I can crack some seeds :sunglasses:


Congratulations, Big Daddy! Happy Thanksgiving to all three of you.


Congrats on the new baby @john818! :man_feeding_baby: :baby_bottle:

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Congrats brother :metal::100:

Congrats brother.

Thanks so much for the congrats everyone :smiling_face_with_three_hearts: It’s been an indescribably awesome week+ since her birth :blush: I’m writing this post with her snuggled up on me :smiling_face:

We have our house to ourselves again so this morning I kicked off the grow by dropping a couple seeds into a cup of luke warm water! I’ve not tried this method before but seeing it recommended by ILGM I thought I’d give it a try.

I also prepared their future grow sites by rinsing and then sanitizing the clay pellets with boiling water and washed my humidity dome and tray with soapy water followed by a wipe down with isopropyl alcohol. Once the tap root is long enough I’ll plop the seeds into Riot Rooters and into the humidity dome they go! While they grow in there I will fill the hydroponic system with 1/4 strength nutes and prepare the temp/humidity in the tent.

Excited to share the progress with the ILGM community :smile:


I’m on my first hydro grow and i have questions for you.

My seedlings are currently in solo cups with a Mason jar acting as the humidity dome. They are in coco coir.

How long do you let the taproot get before putting into the root riots?
Should i have gone from water to root riots? I lost 3 seeds the first time i did that… but i didn’t use domes.


When the tap root is about 3/8”+ long I put it into the riot rooter, root down. I put it in a humidity dome or something to help trap humidity — the bottom of a water bottle with a plastic bag over it works too. Once it’s sprouted I keep a close eye on it, and slowly reduce humidity then remove the dome. It may only be in there for 2-3 days depending on how it grows. One of my two seeds is just barely sprouting, still in the dome. It got a bit confused it appears but seems to have figured out which way is “up” lol.

When the tap root comes out from the bottom of the riot rooter an inch or two is when I move it to the net pot. I remove clay pellets a little more than the height of the rooter, and they should be damp at this depth if not you need to add more solution / increase bubbles from air stones. I squirt some nutrient solution over the exposed pellets then put the riot rooter in there and replace the pellets. I manually top feed with a syringe (just pulling from the bucket) and mist with pH water until the tap root reaches the nutrient solution.

Here’s the one I transplanted the other day, doesn’t even have true leafs yet:

Not to say this is the right way or the best way but it works for me!

At this point I keep the tent real humid and lights at medium power to achieve a low VPD. My first full 24 hour period in the tent averaged 0.6VPD (with leaf offset) which good temp/humidity so I am “cautiously optimistic” we’re off to a good start!

Will keep posting updates as much as I can!