Enter the Monolith: Under Current 10 meets Home Box

  • Thread starter Boylobster
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Ahoy, THCFarmers! here's an update to my DIY Under Current starter system. That thread is here:

That 10-site starter allowed me to plop them straight into their flowering home, here dubbed The Monolith. Here are the specs:

8'x8' Home Box Portable Grow Room (love it)
10-site Under Current system
4 600W Lumatek Ballasts
8" Wind Tunnel 650cfm Centrifugal Fan
1/10hp JBJ Chiller
RO/DI water on auto-fill
House & Garden nutes, full line

But pics are worth a thousand, no?

The starter system:

Ready and waiting, with custom-cut Thermal Armor. I'm hoping this reduces the load on the chiller. Looks cool in any case, huh? ;)

Hardware and control unit:

These Alita air pumps are AMAZING. Two easily replace the stock UC air pump, and are nearly *silent*.

...see? They push.


A very, very large muffler for a very large fan. It does a remarkable job of silencing that monster, however.

Night one of flower - wish us luck! :D

If anyone has any questions about the system, please, feel free to ask. Comments and critiques are warmly welcomed; just be gentle. :)

Thanks for looking!


It looks like you have enough space to put a second UC10 on the other side, are you?


Lolipop Genetics
looks sick man,those are going to be some trees,been wanting to try this system for awhile..


That is a clean setup bro.
The girl's look like they approve also.

Jalisco Kid

If that's a good strain he will not have room for another row. I hope that is attached to a lot of flexible hose. If not do it soon, Look at TK's grow, I'll bet he wished he had widen them rows up before he started and they were twice as wide as yours.Nice to see someone use their hands and mind. JK
Also maybe next time turn 1 row 180* so you have more space between plants and more light penetration.


What is the makeup of your muffler bro? Is it just 2 trash cans or do you have some sort of insulation in there to help muffle the sound?

nor cali farmer

what a nice set up .hope the green gods come through.


How many bulbs are you using, wattage, reflectors or aircooled hoods?


what airstones are those again? They are huge, gotta get some


Deeeeeaaaamn! First, thanks to all for all the kind words and interest. Second, if you ask a question, I'll do my best to answer it in order, but there are a lot, so be patient - this could be a long post. ;)

mcpuffin: The strain is an unknown local clone, I'd say indica dominant. Heavy and compact, skunky, hardy. I've gotten +5oz off this one before (which is good for me) in shitty DWC buckets, so here's hoping...

space101: Another UC 10, that's the plan. In theory, I'll stagger 'em so that I harvest monthly.

Jalisco Kid: Yeah, that was a real concern. Having not run anything like this system before, I didn't know what would be pushing the limits of space efficiency. I've seen Texas' grows, but I wouldn't dare to expect results like his. How would you plumb the Under Current with flex line? You need PVC to match the Uniseals, right? It'd be great to make the system mobile, if I could. Any advice from the master is absolutely appreciated... ;)

Malachi: The muffler is two 35 gallon (chosen for their dimensions, not their volume) trash cans fitted together, and stuffed with quilt batting. The fan floats in the center, supported by the batting. Wire mesh is formed into 8" tubes and fitted to either side of the fan and the ends of the cans. If you like, I can take some more detailed pics, or even draw a blow-up of the system. Just give the word; it makes that bad boy almost completely inaudible outside the grow room.

forknowledge: In the Monolith are 2 600W MH bulbs and 2 600W HPS bulbs. Top down aluminum reflectors, no air-cooled hoods.

Kpezzy: Those air stones are 3.75" Alita Diffuser Discs, same brand as the pumps. Less expensive than high-grade ceramic diffusers, but far better, I think, than cheap blue air stones. This is the first time I've used 'em, but so far, so good.

Whew! I hope that's answered everyone's questions satisfactorily. I'm stuck in for this one though, so keep 'em comin'! :D

Jalisco, I know that this type of setup is your specialty, so if you have some wisdom for me, feel free. You think it's ridiculous to plan for a second UC 10 in that box? As I said, this is my first go at this style of grow, and I never bank on success. :P

'Till next time,


wow very nice my dude! ive been eyein these under current systems for a while now cant wait to see your results!


Haha, you and me both, winta! :D We're gonna' have to wait about 8 more weeks, however. ;)


New pics, and bad news... Buckle up, gentlemen; it could be a bumpy ride. :(

It's night 3 of flowering, and all ten plants seem to be displaying the same systemic problem to varying degrees of severity. Take a look...

Sorry for the fuzzy focus, but you get the idea.



New growth also seems to be affected. Very troublesome.

On a positive note, the root systems seem to be responding well, with white new growth.


It's early yet, but if I can't address whatever this problem is, it's gonna' be serious trouble for me. I've sunk a great deal of time and money into this system, and... well, I'm sure lots of you know what it's like to be counting on a harvest. :sweating

I've dropped half a grand on the House and Garden nutes alone. Speaking of which, here are the details:

- Running completely pure RO
- H & G nutes exactly per their recommendations, but 1/2 strength. That's ~250mL A & B aqua flakes, 100mL MultiZyme, and 30mL Roots Excelurator
- ~750ppm, pH 5.8 and rock solid
- Temps 68-70F
- Daytime temp ~80F, nighttime temp ~70F. Humidity is ~70% at night... this is the only odd statistic I've got.

:sign0065: I've seen plenty of other cats run this *exact* same setup, so how much do I suck? And what can I do about it? This doesn't look like the kind of problem that's going to correct itself.

Experienced opinions are MOST welcome. Sigh.


Have you double-checked ph with another meter or method? I've had similar looking symptoms when ph was off. I was chasing nute deficiencies like calcium or magnesium, when I should have just shifted the ph back to where it should be. That wasn't in an Under Current or DWC system or with H+G nutes, though, so YMMV.


Boroboro: Yeah, I never put too much faith in the pH meter. Unfortunately, a proven chemical test puts the pH right around 5.7-6.0. I *wish* that were the problem. Thanks for the shout, though!

UPDATE: I've received some very sound advice, and have decided to bite the bullet and flush the system. I'm going to start them over with Aqua Flakes A & B only, before complicating the solution with additives. In addition, as they're only 3 nights in, I'm throwing them back to the veg cycle until I can find a solution that works (pun intended). Better to spend some extra time and nutrients now than have them flower for two months under crippling conditions. More to follow.

BTW, I can't speak highly enough about the support I've received from the cats at Current Culture. The root growth should testify that these problems are not with the system, and I'd definitely recommend that anyone who's interested should consider giving them their business. There aren't a lot of people that I feel good about tossing my cash to, but it's nice to know that there are still exceptions. :)

Hooo... back to work. :thinking


Update: Here they are after being thrown back into veg for another few days. They're doing better; the yellowing and speckling that was so acute doesn't seem to be progressing further, but they're not *perfect*, which is what I f$cking want them to be. I'm afraid that that if I flip 'em without having this solved, I'll seriously stunt their yield. However, if I don't flower them soon, it's going to be like wrestling ten green gorillas in that tent. :D I'm pretty sure that the humidity during lights-off was too high, and the dehumidifier arrives on Wednesday. And here they are...

Good from far...

...but far from good. It doesn't show as much in the pic, but there's curling, slight discoloration, and a kind of brittle look in the new growth that I really don't like:

Here's some other weirdness. Deformations like this make me nervous.


But they're still growing! This isn't the biggest of the lot...

And the band plays on. Three different strains rooting - I'll get this bitch locked down if it kills me.

I have an experiment running that should help me troubleshoot - I've started three different strains in a RDWC incubator with *just* Aqua Flakes A&B. I'll be able to see if this strain reacts differently to the H&G basic nutes without the additives, and if the problems are strain-specific. I don't know how much anyone cares about this little struggle, but it's what I'm working on. Perhaps it'll help someone else at some point. :itwasntme


Nice looking setup, I like the pump /stone upgrades you made. Alita seem like very high quality products.
Sorry about your plant problems.. My initial guess is that your light intensity to nute ppm ratio in too high. You say that you are running with 750ppm from the half-strength AquaFlakes-- is this on the 0.5 ppm conversion scale (ie. EC = 1.5), or the 0.7 (EC =~1.1). And how close to the canopy are your lights? Do you notice the deficiency / leaf problems on the plants that are right under the lights? I've noticed that with nute-hungry strains deficiencies will appear on the plants receiving the highest intensity.. some strains need lights a bit higher, and/or more nutrient concentrations to stay happy.
I know the UC system recommends half strength nutes, but that is probably somewhat of a strain-specific recommendation. I'm sure you've had a look at Texas Kid's UC grow ("Here we go.." thread).. and I believe he runs aqua flakes pretty much full strength to their recommendation recipe. So my thinking is raise up your lights and bring up the EC a bit.. and let them get healthy before you flip to 12/12 again. You can always hack a bunch of branches if you fear getting over grown, or trellis and spread out the canopy to accommodate more lights and you might not need to add that other 10 site system...
good luck and keep us posted


There you go, back to basics! Are you using the Alegen Extract from H&G? I have heard that has been known to mess things up in a resivor. Also, if you don't already, get a top-off resivor. Makes life way easy (could leave my garden for about a week w/out tending it) and let's the system do it's thang!
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