RDWC plans, any advice? Plus a few questions.

I want to do an RDWC setup and I think I've got my plans down, I just want to make sure I'm not missing anything.

Here's what I'm picturing in my head:

5 5-gallon buckets, 1 control bucket for adding nutrients and monitoring pH and all that.
Reservoir w/ 30+ gallons, hooked up to control bucket.
Air pump to feed lines to put two air stones in each plant bucket. Should I add two to the control bucket or is that unnecessary?

I'll connect everything with tubing and then have a water pump going inline with the return line.

My plan is to fill the reservoir with RO water, then if my water level drops I'll draw from the reservoir, then evaluate my pH/ppm levels from the control bucket and adjust if needed after adding the RO water. Or is it a better idea to just mix nutrients in the reservoir and then empty it if need be?

With 4 plants in a 4 x 7 area, what should I do for lighting? 600w MH for veg and a 600w HPS for flowering?

Any tips are appreciated, this is my first RDWC grow and I want to make sure I'm moving in the right direction before I start building.

Attached a picture of the plans. Again, any pointers or tips are appreciated.

newgrower14 said:

I want to do an RDWC setup and I think I've got my plans down, I just want to make sure I'm not missing anything.

Here's what I'm picturing in my head:

5 5-gallon buckets, 1 control bucket for adding nutrients and monitoring pH and all that.
Reservoir w/ 30+ gallons, hooked up to control bucket.
Air pump to feed lines to put two air stones in each plant bucket. Should I add two to the control bucket or is that unnecessary?

I'll connect everything with tubing and then have a water pump going inline with the return line.

My plan is to fill the reservoir with RO water, then if my water level drops I'll draw from the reservoir, then evaluate my pH/ppm levels from the control bucket and adjust if needed after adding the RO water. Or is it a better idea to just mix nutrients in the reservoir and then empty it if need be?

With 4 plants in a 4 x 7 area, what should I do for lighting? 600w MH for veg and a 600w HPS for flowering?

Any tips are appreciated, this is my first RDWC grow and I want to make sure I'm moving in the right direction before I start building.

Attached a picture of the plans. Again, any pointers or tips are appreciated.

Click to expand...

Looks like you've done your homework.

As for tubing size, the bigger the better. Small lines can clog easily from roots,etc. and sometimes have problems with the buckets at the end closest to the return pump. If the lines are small/clogged, they can drain the water levels in the last 2 buckets quite a bit more than the rest because it the gravity cannot keep up with the pump itself. I have 2" pvc with uniseals and it can be a pain due to leaks when setting up. Bulkheads would be better imo.

Some people say the more air the better in these types of systems, although that's up for debate I guess. If you technically build an 'undercurrent' system, Current culture recomends .75lpm air per gallon of water. That's pretty darn low. I have a 60 lpm air pump running 28gal (6 buckets plus control). The number of air stones is not as relative as how much air your pump is putting out. I only have a single 2" air stone in each bucket. Seems to be working well. Some growers employ a 'waterfall' technique and do not use air stones at all. The real goal with rdwc imo is dissolved oxygen.

You are going to need to keep your water temps under control to prevent the outbreak of bad bacteria. If you can spring for it, a water chiller is a necessity for these types of systems. You can get away with a 1/10hp. Check craigslist, people use them for aquariums. They are not cheap though (brand new). Otherwise you are going to be freezing water bottles or other not so easy methods to keep your water temps low. Mid 60's is the key. Some people brew teas, or run sterilized systems, but you are going to struggle with higher water temps.

Some people top off with nutes, and some with just ph'd ro water. I just have ro water in my rez, no real reason I chose this method. You can change your mind any time. Make sure you get a ph pen and an ec pen, you are going to need them. You can get them cheap online, or pay up for the brand name gear.

A single 600w light certainly can work for that area, but if you can run more, do it. Goal is (x)grams per watt, more watts, more grams. I have 2 600's in a 4x8 tent. I think I'm going to add a third if I can keep heat under control.

Check out my journal, might save you some time. Very similar systems.
https://www.rollitup.org/t/rdwc-2nd-run-blue-power.885854/#post-12047458
https://www.rollitup.org/t/blackforests-rdwc-2-grow.871178/

Thanks for the response, blackforest!

blackforest said:

Looks like you've done your homework.

As for tubing size, the bigger the better. Small lines can clog easily from roots,etc. and sometimes have problems with the buckets at the end closest to the return pump. If the lines are small/clogged, they can drain the water levels in the last 2 buckets quite a bit more than the rest because it the gravity cannot keep up with the pump itself. I have 2" pvc with uniseals and it can be a pain due to leaks when setting up. Bulkheads would be better imo.

Click to expand...

So 2" or larger for tubing and bulkheads to connect to the buckets? I figure the size of the tubing will influence what type of water pump I'll need, so I'll look into that. I'm sure this is something I can look up, but is there any chance you know off-hand if there's a good formula for what size water pump I'll need? Or how often should the water circulate through all the buckets, I think I remember reading every 4-5 minutes, and if that's the case I can figure out how many GPH I'll need.

Some people say the more air the better in these types of systems, although that's up for debate I guess. If you technically build an 'undercurrent' system, Current culture recomends .75lpm air per gallon of water. That's pretty darn low. I have a 60 lpm air pump running 28gal (6 buckets plus control). The number of air stones is not as relative as how much air your pump is putting out. I only have a single 2" air stone in each bucket. Seems to be working well. Some growers employ a 'waterfall' technique and do not use air stones at all. The real goal with rdwc imo is dissolved oxygen.

Click to expand...

Would you suggest a waterfall system over an undercurrent system? I'd imagine there's pros/cons to both. I was looking through the pictures on the 2nd run journal you have, and that is an undercurrent system and it seems you've had good results, which is reassuring!

I'm glad I'll only need 1 air stone per bucket, that'll cut down on some clutter in the grow area. Do I need to put one in the control bucket to keep the water going through oxygenated, or is that unnecessary?

You are going to need to keep your water temps under control to prevent the outbreak of bad bacteria. If you can spring for it, a water chiller is a necessity for these types of systems. You can get away with a 1/10hp. Check craigslist, people use them for aquariums. They are not cheap though (brand new). Otherwise you are going to be freezing water bottles or other not so easy methods to keep your water temps low. Mid 60's is the key. Some people brew teas, or run sterilized systems, but you are going to struggle with higher water temps.

Click to expand...

Water temperature is a concern, and a chiller is probably the most expensive part I'll need for this set-up. I was thinking about trying to find some way I wouldn't need one, but from what I've read it'll be a worthwhile investment. I'll keep an eye on Craigslist. I have some parts from an old camper which had hot/cold water, so maybe I'll be able to salvage something from that. If not I'll just bite the bullet and splurge on one.

Some people top off with nutes, and some with just ph'd ro water. I just have ro water in my rez, no real reason I chose this method. You can change your mind any time. Make sure you get a ph pen and an ec pen, you are going to need them. You can get them cheap online, or pay up for the brand name gear.

A single 600w light certainly can work for that area, but if you can run more, do it. Goal is (x)grams per watt, more watts, more grams. I have 2 600's in a 4x8 tent. I think I'm going to add a third if I can keep heat under control.

Check out my journal, might save you some time. Very similar systems.
https://www.rollitup.org/t/rdwc-2nd-run-blue-power.885854/#post-12047458
https://www.rollitup.org/t/blackforests-rdwc-2-grow.871178/

Click to expand...

Sweet. So just to make sure I'm understanding it: Plants consume the water, water level drops. Water goes from res to control bucket and fills the whole system back up. That'll throw off nute levels, so after I refill with pH'd RO water from res, I figure let it circulate for a little while then check levels from control bucket and adjust? What do you keep the pH of your res water at, 5.5-6? I figure I'd want to keep it right in the middle of whatever range is recommended for whichever strain I'm growing?

As far as lights go, I guess I'll go ahead and get 2 600s. I plan on putting them in cool tubes with reflectors and having it on it's own exhaust system to help with heat. I've yet to plan on how to raise/lower them as the plants grow or if I'll even need to.

----

Thanks for all the input you've already given, and I'm definitely keeping an eye on your grow. That's a scrog above the plants, right? I have been looking in to that and really want to do it but fear I might be biting off more than I can chew already so I might wait.

If you have any other suggestions or anything, I really appreciate it! Thanks for taking the time to reply above! I figure if I get people who know what they're doing (like you!) to critique my plans then I'll hopefully set myself up for less headache down the road.

newgrower14 said:

Thanks for the response, blackforest!



So 2" or larger for tubing and bulkheads to connect to the buckets? I figure the size of the tubing will influence what type of water pump I'll need, so I'll look into that. I'm sure this is something I can look up, but is there any chance you know off-hand if there's a good formula for what size water pump I'll need? Or how often should the water circulate through all the buckets, I think I remember reading every 4-5 minutes, and if that's the case I can figure out how many GPH I'll need.



Would you suggest a waterfall system over an undercurrent system? I'd imagine there's pros/cons to both. I was looking through the pictures on the 2nd run journal you have, and that is an undercurrent system and it seems you've had good results, which is reassuring!

I'm glad I'll only need 1 air stone per bucket, that'll cut down on some clutter in the grow area. Do I need to put one in the control bucket to keep the water going through oxygenated, or is that unnecessary?



Water temperature is a concern, and a chiller is probably the most expensive part I'll need for this set-up. I was thinking about trying to find some way I wouldn't need one, but from what I've read it'll be a worthwhile investment. I'll keep an eye on Craigslist. I have some parts from an old camper which had hot/cold water, so maybe I'll be able to salvage something from that. If not I'll just bite the bullet and splurge on one.




Sweet. So just to make sure I'm understanding it: Plants consume the water, water level drops. Water goes from res to control bucket and fills the whole system back up. That'll throw off nute levels, so after I refill with pH'd RO water from res, I figure let it circulate for a little while then check levels from control bucket and adjust? What do you keep the pH of your res water at, 5.5-6? I figure I'd want to keep it right in the middle of whatever range is recommended for whichever strain I'm growing?

As far as lights go, I guess I'll go ahead and get 2 600s. I plan on putting them in cool tubes with reflectors and having it on it's own exhaust system to help with heat. I've yet to plan on how to raise/lower them as the plants grow or if I'll even need to.

----

Thanks for all the input you've already given, and I'm definitely keeping an eye on your grow. That's a scrog above the plants, right? I have been looking in to that and really want to do it but fear I might be biting off more than I can chew already so I might wait.

If you have any other suggestions or anything, I really appreciate it! Thanks for taking the time to reply above! I figure if I get people who know what they're doing (like you!) to critique my plans then I'll hopefully set myself up for less headache down the road.

Click to expand...

You can get simple ratchet straps designed for lights to lower/raise the lights. They are cheap. I'm not exactly sure on the water pump recommendations, but I have a 793gph pump running mine and it's 28 gallons. Seems perfect for this system. Get a 'mag drive' pump. If you run a waterfall system where you pump from the control bucket and run an indivudial line to the top of each bucket you could get away with smaller water lines and be able to use flexible say 1" tubing vs 2" pvc I'm thinking. I went pvc on my build so I don't have personal experience with tube lines. The rez is hooked up to the control bucket with a float valve ($4 ebay) so it keeps the system constantly at the same water level, about 1" below the bottom of the net pots. I have an air stone in my control bucket, but I don't think it's necessary, because they are getting plenty of DO. Lots of people have made diy water chillers, so go for it. I'm sure I would have done the same if I didn't get a good deal on a used one.

The net is not technically a scrog where you weave branches and what not. They are there more for support and to help fan out the top of the plant. instead of a scrog, I topped each one about 4 times so each one has 8-12 heads on them. The idea is to get an even layer about 8-10" above the top of the upper layer. If I had fewer plants in the same area a scrog would work but since I have 6 in this small area, they basically scrog themselves. The goal being an even canopy. My biggest suggestion is that if you are going to exhaust this much time and energy, make sure you are growing a nice strain. It's a waste of time and energy to grow crappy strain bud imo. I've grown plenty of awesome looking and smelling crappy bud.

Do you have your water pump on a timer of some sort or does it run all the time?

I've seen people mention float valves - but it slightly confuses me. If the plants consume water, then you add water automatically from the res without nutrients, will that mess anything up by "diluting" the water that's already in the buckets? Or as long as I check it every day should I be fine? I'm not sure if that question makes sense or if I'm just over complicating it in my head.

I plan on ordering feminized seeds online, I've looked at a few places, but I'll do more research as far as where I order them and the best strains that will suite my space/system/experience. I figure that's the best route to go. Might do an autoflower strain my first go around, but I'm not sure. I know there are pros and cons and ultimately I'll go with non-autoflower seeds, but might try that just so I can get a hang of maintaining the plants and all that.

Check out the seed/strains section so you can get a good idea of what to order online. Try to find some journals of the type you want to grow. I'm looking for new strains all the time. If you find a brand you like check their twitter,etc. to see if they are going to do a new seed drop soon. Just some suggestions for you.

Yes, by having the rez with ro water, it will 'dilute' the nute solution. Plants will choose when to uptake nutes, or just water. If you are changing your water every say week, you are looking for your ec to drop and ph to rise during this cycle. That means they are eating. My ec is kinda high at 1.6-1.7 when I change out the water. Some people run much lower ec's. This strain seems to like these levels, so all I can say is that it works. I try to keep my rez at 5.5 ph because as they feed, ph rises, and this helps kinda balance the system, at least it does for me. It usually tests at 5.7-6.0. I start it at 5.5 when I change out the water. Keep your grow area as clean and sanitized as possible. In the end the plants will tell you what they want or need, you just have to find a way to get it to them.

Bigger pipe is MUCH better. I used 4" on mine. Doesn't require a bigger pump at all. As stated above, the bigger the pipe the less difference in water height between the buckets.

There IS a way to make a cheap and very effective chiller. You use a dehumidifier, take it apart, bend the cooling coil CAREFULLY, into a cooler full of water. Now take a small pump and pump the water from the cooler and through 25' of stainless steel tubing. You can get them in ebay. Search for wort chiller.

I have used many of these and they work spectacular. We even have one working in our commercial WH right now. A 70 pint dehu will chill 250 gallons down to 60 easily.

Look on CL for a dehu. You can find them cheap and any one will do. The only feature it needs is an instant on. Meaning you plug it in... and it turns on. That way you can put it in a timer based in how cold you want the water.

It looks totally ghetto, and my buddy used to give me all this shit for mine until he actually saw it keep an entire 250 gallon IBC tote chilled to 65 in an 80 degree room.

Other tips... POND MASTER air pumps!!!! Do NOT buy those active air piece of shits. 2" round airstones, new ones every run. Use beneficial teas. Religiously, no matter what douche bag that comes along and says "I run sterile with 70 degree water and I'm fine"

65-67 degrees and teas. That is how you avoid heart ache with DWC.

Cheers and good luck.

Oh yeah, we never change our rez, just add fresh water and nutes. Lower ph for veg and higher ph for flower... my loves that magnesium and calcium.

newgrower14 said:

So just to make sure I'm understanding it: Plants consume the water, water level drops. Water goes from res to control bucket and fills the whole system back up. That'll throw off nute levels, so after I refill with pH'd RO water from res, I figure let it circulate for a little while then check levels from control bucket and adjust? What do you keep the pH of your res water at, 5.5-6? I figure I'd want to keep it right in the middle of whatever range is recommended for whichever strain I'm growing?

Click to expand...

I've seen people mention float valves - but it slightly confuses me. If the plants consume water, then you add water automatically from the res without nutrients, will that mess anything up by "diluting" the water that's already in the buckets? Or as long as I check it every day should I be fine? I'm not sure if that question makes sense or if I'm just over complicating it in my head.

Click to expand...

No that is not how it works.

If you're trying to add auto top off to your equation, you will need a float valve to regulate when its time. Its simple, when water levels drop, the float valve would trigger a pump to auto top your RDWC system until the desired level is achieved.

In your diagram, your reservoir is acting like an extension of your control bucket and will become part of your nutrient mix. And if your plan was to fill it higher than your buckets, you will flood your buckets and make a huge mess.

Scrap the idea of auto top off reservoir IMO. Make the control bucket larger if you want and use that as your reservoir/control bucket - the extra water will decrease the frequency of necessary top offs, while also stabilizing your Ph and water temperatures. Plus small scale growers love messing with shit so you'll love the labor required to top off which will keep you from getting too bored lol.

Also, Id scrap the idea of undercurrent and uniseal based bucket system unless you have money to spend on large bulkheads. The uniseals will be a pain in every aspect from assembly, to leak control, to clean up. If you dont want to spend the money on the large bulk heads, you can get away with a simpler, easier to maintain system using 1" vinyl tubing. It won't be an "undercurrent" system but you can keep the pump submersed in the reservoir while feeding water to each bucket using 1/2" tubing. Gravity will keep it all level and your DO will be higher by taking advantage of that waterfall effect being generated by the returns in each bucket. Still RDWC and tremendously effective, just not "undercurrent."

Idk how to make cool schematics but the design would look like the attachment

Parts needed:
1 Water Pump (ecoplus 396 would be perfect)
3 1/2" Barbed T fittings (to split the return lines)
4 1/2" grommets (to insert the barbed elbows for the return lines)
5 1/2" 90* barbed elbows
5 buckets or other totes
10 1" barbed tub outlets (bulkheads)
1" Vinyl tubing (length varies based on spacing, 10' should be plenty
1/2" Vinyl Tubing (Length varies again based on spacing, 10' should be good again)

You can also add an additional 1/2" grommet to the bottom of the control bucket and another barbed 90* elbow with some tubing for a fill/drain fitting which will almost certainly prove to be handy at some point.

Cheap, simple, effective, and leak free.

Edit: I left out the airpump and 4 airstones but yeah one per grow bucket

Major Blazer said:

No that is not how it works.

If you're trying to add auto top off to your equation, you will need a float valve to regulate when its time. Its simple, when water levels drop, the float valve would trigger a pump to auto top your RDWC system until the desired level is achieved.

In your diagram, your reservoir is acting like an extension of your control bucket and will become part of your nutrient mix. And if your plan was to fill it higher than your buckets, you will flood your buckets and make a huge mess.

Scrap the idea of auto top off reservoir IMO. Make the control bucket larger if you want and use that as your reservoir/control bucket - the extra water will decrease the frequency of necessary top offs, while also stabilizing your Ph and water temperatures. Plus small scale growers love messing with shit so you'll love the labor required to top off which will keep you from getting too bored lol.

Also, Id scrap the idea of undercurrent and uniseal based bucket system unless you have money to spend on large bulkheads. The uniseals will be a pain in every aspect from assembly, to leak control, to clean up. If you dont want to spend the money on the large bulk heads, you can get away with a simpler, easier to maintain system using 1" vinyl tubing. It won't be an "undercurrent" system but you can keep the pump submersed in the reservoir while feeding water to each bucket using 1/2" tubing. Gravity will keep it all level and your DO will be higher by taking advantage of that waterfall effect being generated by the returns in each bucket. Still RDWC and tremendously effective, just not "undercurrent."

Click to expand...

This is bad advice

Float valves do not require a pump. When the water level drops, the float...that floats on the water surface...also drops, opening the valve and allows water into the system until the float closes the valve....look in the tank of your toilet if you need a visual. You can adjust your water level in the system by adjusting the float valve.

Do not scrap the top off res. It's what makes RDWC much less maintenance than DWC. If your using a float valve, it will not flood unless the float breaks off or for some reason it sticks open....both unlikely unless the operator is doing something dumb.

In RDWC the piping connecting the control bucket to the plant sites has to be bigger than the pump inlet/outlet dia. For instance, most mag drive pumps have 1/2" NPT connections. So if you plumbed the entire system with 1/2" tube/hose/pipe, you will have unequal levels in the sites and possibly an overflowing control bucket. It needs to be atleast twice the size for proper flow and then some to accommodate blockage from roots being pulled into the downstream pipe.

Sorry had a stoner moment about float valves confusing in my head with controllers in nice ebb flow setups. My advice isn't bad though, my system works 100% (I use it haha) and I only suggested 1/2" return lines with 1" lines on the bottom of the buckets keeping the system level and no inline pump but a submersible pump in the res/control. The op's original design has nothing regulating his remote res if you peep his original posts, he'd flood his shit for sure and I was trying to keep that from happening. Anyway sorry abt my float valve brain fart you are 100% on that!!

Major Blazer said:

Sorry had a stoner moment about float valves confusing in my head with controllers in nice ebb flow setups. My advice isn't bad though, my system works 100% (I use it haha) and I only suggested 1/2" return lines with 1" lines on the bottom of the buckets keeping the system level and no inline pump but a submersible pump in the res/control. The op's original design has nothing regulating his remote res if you peep his original posts, he'd flood his shit for sure and I was trying to keep that from happening. Anyway sorry abt my float valve brain fart you are 100% on that!!

Click to expand...

Regulating the res?..maybe your still having a stoner moment.

The float valve does the regulating...

He didn't mention using one and I offered a simpler, cheaper, and very effective setup. I hate uniseals on buckets. If you've had good luck with them, bless you. I have 3 sites and a very stable system without needed a large rez. Plus I like having to manually top off.

Using a top off res, I can easily go a week without needing to do anything.

No doubt man. I'm not discounting the merit of a large rez at all, sorry if you got that impression. I just don't see it as necessary in small scales and measuring, topping off, and nutrient addition is a labor of love for me!!

I bought a $5 float valve with 1/4" water line fittings running about 12' to a 10 gal rez tank. I'll change it out to a 32 gal container here soon. My small 6 site system can drink 4+ gal a day when they are rolling. Rez tanks have a 1" bulkhead with npt to water line quick connect ($10). Just make sure your rez tank is above the water line and gravity will keep it constantly topped off. It's a nice visual too because you can see how much they are drinking every day. In my small 28 gal system, they can drink 25+ gal a week. Another nice feature is you can set the water level, so I keep it at the bottom of the pot in the beginning and when roots are thriving, I lower it below the pot. Never have to worry about where the water level is. I usually change out the water, fill the rez and don't touch anything for at least a week. $25

Thanks for all the advice everyone, and especially you, blackforest! I promise I'll start a grow journal when I get everything planned out.

Also thank you legallyflying for the tip on the DIY water chiller. I am on the lookout for the parts for it. Is it pretty much trial and error as far as using a timer to run it in order to keep the water in the right temperature range?

I've been doing some more thinking and planning, and I'm pretty set on doing the 5 bucket w/ control + rez and I'll do the float valve from the rez to control bucket the way blackforest describes. I'm leaning towards trying an autoflower strain (I've heard good things about Dutch Passions' Think Different seeds) and going from there. Then as long as the system works I'll only have to really worry about nutes and the grow environment, as far as I know. Still unsure on what to do as far as lights go, there's so many options and opinions that I'm having a hard time narrowing it down. Just need to hammer out the best way to use my space. I'll have an 8x10 area that I could split into multiple smaller rooms if need be, which was the original plan. Kind of moving back to the drawing board.