8 place UC DIY build - parts/price list

Hey RIU. So, I'm building a replica of a CCH2O UC8 DWC system. If you go to - http://cch2o.com/under-current-instructions/ - its basically everything you need right there to start building your own. Their standard 8 site system w/ 8 gallon square containers and 2x 5.5" net-pots is selling currently for $1377. This is what I'm going to be building and my total was about $500 before the chiller.

Basically, all of the information in here can be found by digging through stickys and old forums.. but the write up sqydro did is older and the original pics no longer load so, being that I've done the homework and piecing together, I figured id share my experience. I would suggest anyone considering this build have basic understanding of how these systems work and some experience plumbing or making shit stop leaking.

Lets start with the parts needed and what they'll cost you if you decide to pull the trigger on this BADASS little project.. Prices are what I paid - you can most likely find some things cheaper - I TRIED to source materials locally. The bulkheads and 8 gallon totes were ordered online everything else from local hardware stores or hydroponic shops. Pool/ pond supply stores may have things you need. If you live in a non-rec/med state where hydro shops may not be so popular, they have the pumps and related things..

- 8 gallon Sterilite black totes 6-pack@Walmart.com for $40 I bought 2 6-packs so $80
- 2" slip x thread bulkhead fittings amazon $6.50/ea x17 ~$110
- 6" net pots $1/ea x16 $16
- 550gph active aqua inline water pump $38
- 70L/min active aqua air pump $53
- 3/4" RAINDRIP pipe thread inline "Y" filter $20
- 2"x10' piece of PVC pipe $8
- 3/4"x10' piece of PVC pipe $5
- 2" PVC fittings are $2-3/ea - four elbows - one 2" T - and one 2"x1/2 T about $15 altogether
- various 1", 3/4" and 1/2" PVC fittings and ball valve ~$25
- Clear 3/8"x20' hose for air pump $10
- Clear 1/4"x25' hose $4 at Walmart same place for cheap good quality air stones @$3-4/ea
- Black 3/4"x25' hose $23
- you'll want one big disk air diffuser for the epicenter bucket $23



Total at this point is around $500 and its expandable/upgradable. I think I'll be using a 19 gallon epicenter to expand system capacity in an attempt to not use a top-off res. If you wanted to use one as a top-off the way the UC8 is supposed to be set up you will need a float valve and whatever size bulkhead/uniseal you decide to use for the res itself.
Some stuff you may want to make your life easier..

- PVC Glue ~$10
- thread tape/sealant
- Silicone or similar elastic/water resistant sealant $5-10
- Float valve found in hydro stores usually with 3/8" thread for around $15
- 19 gallon sterilite tote $8
- Chiller. this is the one big item.. you'll probably need one. I paid $280 for a 1/10hp Active aqua unit

I grew for years in DWC buckets in a basement with no chiller -water temps 60-75 and never any root rot. recent move has my grow space on the second floor and now temps are way up there as high as 85. plants seem fine but the need to chill water is what sold me on rDWC/UCDWC. I'll be setting up the epicenter and return tube. Also, determining bucket spacing and making the supply and return manifold - that will be the first "build" post.

Return manifold T (2"X1/2") coupled to 1/2" ball valve which connects to the inline filter before heading to the pump inlet through a length of 3/4 PVC. This rear manifold receives water from rear buckets and feeds the pump inlet.

Pump inlet - a short piece of 1"clear tubing connects to 1"barbed connector stepped down to 3/4" slip for PVC to connect to the return manifold.

Outlet of pump will return water to our epicenter through 5/8" or 3/4" hose and a uniseal/bulkhead.

Cutting the holes for bulkheads needs to be done carefully and then the holes need to be cleaned up. I'm using 120 grit sandpaper to do this. Worked great for the first one. For these bulkheads the manufacturer recommends using a 3" hole saw and that's what I have anyway. But it's little bit big. 2 7/8 would probably be a better fit. A smaller hole (1 1/4"I think) will then be drilled into the epicenter bucket for the pump return.

* a tip the guy at the local pond supply shop gave me when I was in there looking for bulkheads is to drill the 1/4" pilot hole and then switch the drill to spin backwards and cut with the hole saw slowly in reverse. Worked great.

Looking good bro. You got a really good deal on the bulkheads. I use 3" and I couldn't find them for less then 10-15$ so it was out of the budget. I ended up with uniseals.

two suggestions:

1) that clear tube might get algae
2) sign up for an amazon affiliate links acct and link to all the products you bought in case anyone buys them you get some extra coin.

Twerkle said:

Looking good bro. You got a really good deal on the bulkheads. I use 3" and I couldn't find them for less then 10-15$ so it was out of the budget. I ended up with uniseals.

two suggestions:

1) that clear tube might get algae
2) sign up for an amazon affiliate links acct and link to all the products you bought in case anyone buys them you get some extra coin.

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Thanks man.
The cheaper bulkheads I ordered actually didn't show!! So I re-ordered with two day shipping from another company (still amazon) so hopefully I'll be building and posting more on this soon. I won't use the uniseals I heard people were having some leak issues and even tho Im sure I could seal em just fine, I'm just steering clear. The clear tube is what was available without buying a whole roll. More or less just to throw SOME of it together and take some pics. And If I could find the right fitting I'd go PVC right out of the pump. (Idk if it's a good idea but it'd be solid that way) But It's weird as hell tho - not any size standard pipe thread. I can cut down the clear tube so the barb fittings butt up against each other probably eliminate most of the light that way.

Any comments/input is much appreciated.

The thread in/out of the pump should be regular 3/4" NTP. My chiller pump is connected with NTP to PEX brass peice.

the uniseals we're annoying thats for sure, only had two leak out of 29 buckets tho. After looking at your hole prep you would be fine with uniseals. Most people rush it and dont sand and they leak. The 3m marine caulk is really good too.


I like the inline filter on the return thats a good idea.

I added a pvc tee with a threaded top that i capped incase I wanted to add a probe in the future. https://www.atlas-scientific.com/product_pages/components/probe_pipe_fittings.html

Twerkle said:

The thread in/out of the pump should be regular 3/4" NTP. My chiller pump is connected with NTP to PEX brass peice.

the uniseals we're annoying thats for sure, only had two leak out of 29 buckets tho. After looking at your hole prep you would be fine with uniseals. Most people rush it and dont sand and they leak. The 3m marine caulk is really good too.


I like the inline filter on the return thats a good idea.

I added a pvc tee with a threaded top that i capped incase I wanted to add a probe in the future. https://www.atlas-scientific.com/product_pages/components/probe_pipe_fittings.html

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The probe idea is awesome. For EC and/or ph I'm assuming..? Once I'm up and running I will be jumping all over upgrades like this. I want a constant ec/ph monitor. I haven't looked into it but DO monitor would be a pretty sweet idea too, if it exists.

Porkymcchops said:

The probe idea is awesome. For EC and/or ph I'm assuming..? Once I'm up and running I will be jumping all over upgrades like this. I want a constant ec/ph monitor. I haven't looked into it but DO monitor would be a pretty sweet idea too, if it exists.

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that company sells all of them and they hook up to a rasp pi or arudino. the yoi can host a web sserver on one with charts. thats my plan. i have the T for my temp and then gonna put the rest of the probes in the rez. my chiller cools the rez so i want tovknow what temp it is going into the bucket not the bucket temo

Twerkle said:

that company sells all of them and they hook up to a rasp pi or arudino. the yoi can host a web sserver on one with charts. thats my plan. i have the T for my temp and then gonna put the rest of the probes in the rez. my chiller cools the rez so i want tovknow what temp it is going into the bucket not the bucket temo

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Awesome I'm gonna have to price out the sensors and try and get a handle on how much coding it will take. I have a few arduinos already. I'm not great at writing code but I kick ass at copy/pasting sample code chunks together lol. Gonna have to break em out and start tinkering. I have an arduino sd card reader makes it super easy to set it up as a sensor reader/ data logger.

following for sure, i want to do something similar to fill a 10x10 space, thinking a 16 pot or 24. but yeah DIY is way cheaper

Those raindrip filters are a finer mesh than the ones that UC supplies. I have a UC as well as a system that I also built, based on their design - and that filter plugged every day. Screens that fine are meant for clean water and the root material will plug it every day. I'm still trying to find somewhere to get one with a bigger mesh.

Here's an 80 mesh that would work well - https://www.sprinklerwarehouse.com/Drip-Irrigation-3-4-Stainless-Steel-Screen-Filters-s/8644.htm

FennarioMike said:

Here's an 80 mesh that would work well - https://www.sprinklerwarehouse.com/Drip-Irrigation-3-4-Stainless-Steel-Screen-Filters-s/8644.htm

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This is why I posted the build up. I wanna know what went wrong when other people did this so I can do it right the first time. So ya thats good info I have a sort of P-trap that I was gonna put before it to catch bigger sediment but decided it was kind of redundant as there's no heavy stuff in the soup for it to catch - roots bits will flow right through it so I'm not gonna bother.

I decided to go with a waterfall style return in the epicenter with air stones in the buckets - NOT in the res. Seems to be working ok so far. I cut a piece of 3/4" PVC and drilled a row of 3/16" holes through it. Used parts from an ebb and flow drain/fill kit I had around to pass through the wall of the epicenter bucket. Some PVC pieces with an o-ring on the liquid side. I wouldn't trust it below the water line but it's fine for this. The res is separated from either grow spaces and the chiller hangs out in the flower room by the AC til I can find something better to do with it. Stuck some fish tank temp strips on the res and a couple buckets. Great to have a quick visual on temps.

I'm just waiting on parts and chiller to arrive, going to be making a 3 x 35l tote system and 84l res. The 3 x totes have to be run in a straight line as my cab is rather narrow. Has anyone done a uc build this small?. Could do with a simple diagram on how it should be laid out.
Feel free to pm me if you can help out and I will start my own thread, rather than break this great thread up.

zypheruk said:

I'm just waiting on parts and chiller to arrive, going to be making a 3 x 35l tote system and 84l res. The 3 x totes have to be run in a straight line as my cab is rather narrow. Has anyone done a uc build this small?. Could do with a simple diagram on how it should be laid out.
Feel free to pm me if you can help out and I will start my own thread, rather than break this great thread up.

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I know people have done rDWC that small. No reason why you couldn't run a small UC. Having the totes in a single row would be better. There's potential for one side of my system to flow more than the other.

If you go for a larger res, your water level is going to be consistent across all connected buckets in a UC, so same height but longer/wider for more water volume. Taller container for your res won't help you. The floor that the system will be on, needs to be level for the same reason. No matter what the configuration/orientation of the buckets, it's placement of bulkheads that is important - You want flow across the entire area inside the buckets.

Other than that, make sure the rear manifold that collects water for the pump inlet has a ball valve. It will provide you control over the amount of overall flow in a smaller system with larger pump.

Draining them is a bitch. I have a small (160 gallon/hr) pump with a I use with a hose to a drain. Doesn't drain 100% of the water. Basically, anything below the bottom of the bulkheads won't drain- I just leave it and add fresh water.

Good luck building

Any idea what to use instead of bulkheads? Would cost me near $300 just for 17 if them over here in aus lol.

rayuki said:

Any idea what to use instead of bulkheads? Would cost me near $300 just for 17 if them over here in aus lol.

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Uniseals. I believe they're about half the $. I hear if you have square containers and carefully drilled holes they seal great. Bulkheads are more idiot proof and for me was a no brainer.

Porkymcchops said:

Uniseals. I believe they're about half the $. I hear if you have square containers and carefully drilled holes they seal great. Bulkheads are more idiot proof and for me was a no brainer.

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Yeah I can find bulkheads but at near $20 AUD a pop it's a bit rich. Would unseals work in round buckets you think?

rayuki said:

Yeah I can find bulkheads but at near $20 AUD a pop it's a bit rich. Would unseals work in round buckets you think?

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Uniseals suck ass. Especially on soft walled round containers. I would avoid if you can come up with a bulkhead option.
They (uniseals) seal great to the pipe but you will be gooping up between the seal and container wall unless you have a flat and very rigid container
Plus the larger sizes take huge strength to get the pipe in. Something that may be an issue for some.
Yes, I have used them - you can see them in my vertical grow linked in my sig