Rdwc nutes questions

[Swedge]

So I'm nearly finished my soil grow I'm going to do a rdwc setup next using 4x 5 gallon buckets with a 20gallon reservoir I'll probably only fill the reservoir 3/4 though

My question is about ppm

I'll be using general hydroponics flora 3 part series

If I'm using 1/2 strength nutes does that mean my ppm will be half?

E.g if the flora feeding schedule says I should be around 1000/1200ppm but I'm only doing half nutes should I be around 550+ whatever ppm my water is?

Also is it worth setting up a top feed drip system untill the roots reach the water or just run the water right up to the rockwool?

If I rub a top feed drop does that mean I need to alter the nute strength?

Cheers

 

[Papageno]

I am reading a lot of stuff on this as I want to build an undercurrent system next. I think you are talking about an undercurrent system. Lots of people call them RDWC but that is actually a different design. If you search for RDWC on the net you will mostly find Undercurrent systems. Technically speaking an RDWC does not have a separate res. You could do it but it doesn't make a lot of sense you should just do an undercurrent if you are going to have a separate res.

reference this
Tutorial - DWC vs RDWC : Abergreen, DIY Hydroponics Systems and Kits, Hydroponic lights, Envirolite
and
Current Culture H2O - Hydroponic Systems and Nutrients ... download their manual and you can build one yourself and also most of your questions will be answered.

If you are intending to run the water out of the site buckets, with pipes at the bottom of the buckets through a return to an "epicenter" using a bottom return then you are talking and under current system. It is really a hybrid between a standard DWC and a super high flow NFT. In an RDWC system the "recirculating" refers to a pump (typically in the same res as the plant) that pumps (typically sprays like aeroponics, again another hybrid) water from the bottom res where the nutes settle to the top (see above link). Some people also call them Recirculating Undercurrent DWC but I think technically that is still wrong as you are not in the strictest sense recirculating (it is being extracted, mixed and then reintroduced). It doesn't matter...who cares...I am just answering below assuming you meant Undercurrent based on your description. Undercurrent is clearly the way to go if you have the space.

I have a hybrid RDWC but instead of spraying like Aeroponics I drip from the top as you describe. After having used it I think the top drip is unnecessary as my air stones do plenty of agitation.

Again I have not built and undercurrent system yet but I am going to next and have been researching looking for the parts. I have done a lot of reading on it and based on my research I can answer a few questions but again I have no experience with Undercurrent.

1) First off yes half strength is half PPM.

2) I believe that running a top drip in an undercurrent system is a waste for multiple reasons. Yes just run the water level up to the bottom of the net pot in the beginning but even that should be unnecessary. A good DWC system and Undercurrent DWC has air stones in each site large enough and pumped with enough air to cause bubbles to get to the lid and keep the entire net moist. You should have a good wicking medium that will suck in that water. Enough said.

3) Most people running undercurrent I have read are claiming they can run nutes at 1/4 strength. The increased oxygenation and nutrient distribution improves uptake. Put this into google and look at images... "undercurrent DWC roots" you will bust a nut.

4) If you run top drip into this, which no one else has done that I have seen, then the same rules still apply. No nutes until they have a few nodes then only at 1/4 and increasing each feed. But if max is 1/4 then 1/4 of that is 1/16. Again I never have run this setup but I will be later this year. I can't find a good parts list and DIY instructions out there other than the manual I suggested you download above. But I am an engineer and can figure it out. So I am going to document and post a DIY here with parts list when I am done.

another good read from another forum...
https://forum.---------.com/hydroponic-growing/876929-diy-undercurrent-dwc-system-pics.html

They wont let me post that one here LOL... but add --------- where the dashes are.

LOL that didn't work...how about with a space in the middle (remove the space) grass city

 

[Swedge]

Thanks for the great reply I'm currently growing In a 1mx1mx2m tent with a 600whps

I was Intending to use 4 small 5gallon totes but it would be too cramped so have changed to 4 5 gallon round buckets for more room for my fan etc

I always thought that it was called a rdwc since when I google it it comes up as an rdwc but like you said peopleuat all be calling it that

I think I'll pass on the top feed for the moment and run the water pretty high

Still got to decide on net pot size and rockwool size I'll be using hydroton as my medium with the rockwool

Does rockwool and net pot size matter?

I'll go have a look at your links and thanks again

 

[Papageno]

I am looking to use 8 gallon not 5. The rule of thumb is 5 gallons per plant so you can't do that in 5 gallon containers. they get a bit more expensive but I am going to find a way The dealio is that you actually don't want the roots in the water. DWC only works if you have good air stones to aerate the water. Otherwise the roots choke and die as they need oxygen. Anyone who has grown in soil will tell you all about over watering. The undercurrent method does both by having large air stones and continuous flow. You could perceivably run the water at half full and get better aeration as the top roots are permanently in the air. If you have an 8 gallon bucket it is easier to keep 5 gallons per plant and let the roots breath. All that said tons of people do it in 5 gallons just fine. But all of the pro stuff you buy for 3 grand is 8 gallon or larger. I found some cheap good ones online but the shipping is same as the pail so they aren't so cheap. Like I said I am still looking.

Someone will probably yell at me for clarifying but I wanted to answer the actual question you asked and if not we could change the answer but I think they apply wither way.


Net pot size is something I was going to post a question about. The guys here at one of my shops told me it doesn't mater for DWC because the roots go straight down. Once they hit the water they stop growing sideways. I am not sure I believe that so much. The best reason for larger net pots is stability. It is easier to handle plants in 10 inch pots that are 4 feet tall then in 4 inch pots. They will topple over and need more aggressive tie backs to keep it straight. Again the pro stuff is 10 inch pots.

I don't use rockwool for a few reasons which you can easily find discussed somewhere else on this board. It is a fairly religious debate where many people are adamant that they are fine and others refuse to use them. I refuse for a number of reasons I wont go into. When done correctly they work fine! Size of the rockwool is irrelevant. Get the smallest ones, probably less chance or root rot from them that way but I don't know I don't use them.

 

[Swedge]

What do you use instead of rockwool? I won't be starting from clones either I'll be starting from seed

 

[Swedge]

Also I'll be using 3/4" return pipes and 1/2" feed pipes along with a 320gph water pump and a 400gph air pump

Any recomendations on air stones? I've seen people talk about a kind of hose which has holes in it and can't be shaped in the bottom of the bucket?

 

[c526]

thats a good size air pump,that monster water pump could heat the water up,I ended up(same one) relocating it to inline instead of in bucket. you will run into troubles if you veg to long with the 3/4 and 1/2

nothing worse than coming home and the tent/first floor is flooded,the roots WILL clog them up at some point.its happened to plenty to some on here.

rapid rooters work well for seed and dwc

 

[Swedge]

What size do you recommend for the feed and return

I'm trying to find larger tank connectors to connect up to my buckets and resevoir

My pump can be ran externaly so that's no big problem

Also can I connect all my returns to 1 pipe then back to the resevoir or better having 4 complete returns pipes to the resevoir

 

[c526]

2inch is the safest bet,they sell fittings from 1/2 up to 3 inch,so the choice is yours.I just know that after 2 runs with the smaller lines i about had it,I could only veg about 4 weeks or the roots got silly towards the end of flower

i only had 3 lines coming into reservoir,one for the left 1 for the right and the return line right down the center,
something like this

0-0
|||
0|0
|||
.R

 

[Papageno]

Well lets see which question to answer first...

As established I think you are doing Undercurrent not RDWC so the heat from the pump is not so much an issue as the pump is not submerged.

For specs again I would follow the design by that company I left the link for above. as I understand it they invented this and there is a pile of not so obvious science behind what they did. Here is a distributor that has the spec listed on one page for all sizes. I would still build it myself because the specific layout is something you need to size with the tubes.

Under Current UC System - Current Culture

They are using 2" tubes in the system before the return. There is also an inline filter and a ball valve on the return line after the rear manifold that are necessary. My understanding is the valve is used to increase pressure (explained in a moment) since the pump is single speed. And obviously the filter is for roots and other crap. You have it backwards, with smaller pipe first and larger later. Part of how this works is the vortex in the tubes aids in turbulence. You are reducing this by going bigger at each step. As you go down in tube size it gets harder and the water must go faster under higher pressure for the same flow rate. So what they have built will cause the water to become more agitated as it travels until it gets to the epicenter again. Then it relaxes and starts over. What you are doing going from 1/2 inch to 3/4 is making it easier for the water to travel under less pressure at a lower speed. Look at the exact design they made as there is a bunch of science behind it. By having a single speed pump and adding the ball valve to reduce the opening between the manifold and the return pipe the water must travel very fast and at a high speed to achieve the same constant flow the pump is trying to put out. This turbulence is a good thing.

They are using a super awesome air pump that is super expensive ($140 for the 4 site system). The system is expensive because they are using good stuff that wont break very easily. The biggest problem people have with DWC is failing pumps that cause death when you are away for a few hours. So expensive robust parts are crucial to getting this right. Who wants to come home to a bunch of dead plants. Another good reason to have larger containers so the water level is well below the net pot.

Air stones...man there are a lot out there. I got some disk ones that got good reviews from amazon. Not okay reviews. good reviews. you want heavy ones that will sink to the bottom. The tubes are also great and that is what comes in the expensive system, I have been talking about. But I have also seen that same system with large I think 9" disk ones. The tubes are nice because you can fill the edge of any shape container. Airstones will need to be cleaned after each run and eventually replaced, they are a throw away item really.

Okay I think this is the last one...instead of rockwool I use peat plugs. There are 2 companies that make great ones just for us (there are many more and you can get this kind of stuff even at Home depot and almost anywhere). General Hydroponics and Mad Farmers. you can buy a bag of 50 I think GH replacement plugs for cheap on amazon. Down at my grow shop I picked up a tray of mad farmers peat plugs that fit in the starter hood perfectly.

Amazon: Mad Farmer Root Tray 50 Count Starter Plugs for Cuttings Seedlings

Amazon: General Hydroponics Rapid Rooter Replacement Plugs

Again my hydro store had a starter hood with vents that this fits in perfectly. The tray has a large hole in to bottom of each site so you can check to see when the tap root has exited and transplant at that point before it bends or you get root bound.

 

[c526]

lmao@VI bro if ya keep putting those non sponsor links up,we wont ever get to see what you have,,bossman doesnt like off site linking,just friendly advice

 

[Swedge]

Thanks will have a proper read when I'm home from work reading on my iPhone ATM

Am I right in guessing the return has to be larger diameter than the feed to stop over flowing?

 

[c526]

for about 25 bucks you can build a system,2 inch all the way around and 1 inch down the middle,and contray to belief,the pump can go inside or out,the benefit to inside the control bucket is dissolved oxygen,put the hose near the top and allow the waterfall action to add oxygen,the downside is it heats the water about 6 degrees more.
Ive never used valves,I can see the use,but only to isolate buckets,the water blasting through with a 320 pump takes a minute to get use to.I can hear the system running over fans

the biggest hassle with ANY of these setups,they are VERY hard to move,even a little so ya better be happy with its placement,right from jumpstreet

I use to grow 6-8 zips,with this system and after I switched a couple of years ago,I now do pound a plant with RW top feed.

basic everyday parts at blue box store,use a little aquarium silicone and done

cut on the INSIDE line,so it HAS to thread in

 

[Papageno]

LOL

I just try helping when I can for the Karma points because I am always on here asking dumb questions. I am not pushing any one product. I am just adding links for reference but yeah if I get kicked off... it is the internet....There are lots of places to ask questions.

And I agree the pump can be submerged but it doesn't make much sense to me. There are multiple benefits for following their design and there is at least the one obvious downside to submersible.

Where are you getting your bulkheads from? That is one of the harder parts to get cheap.

It looks like you are using round buckets. I am looking for square ones for a better seal. I found some great ones for a decent price that had those flip up 1/3, 2/3 lids but the shipping was near the same price as the bucket so it ran them up to something crazy. But really it all comes down to the bulkhead and being able to maintain the seal. Given a good enough bulk head I could do a round one but I also want larger than 5 gallon buckets.

 

[Swedge]

Cheers for the pic what type connections do you use? Push fit? Solvent?

 

[c526]

LOL

I just try helping when I can for the Karma points because I am always on here asking dumb questions. I am not pushing any one product. I am just adding links for reference but yeah if I get kicked off... it is the internet....There are lots of places to ask question

lmao,I know man,sometimes they are picky sometimes not,I think you have something to offer,thats why i Gave the heads up.

those supplies were from lowes,amazon has some sweet ones purpose built for about 8 bucks(shit I did it now lmfao)

IF and its only as good as it was made,the pump leaks on the outside,(and it has happened to me)then the whole system drains,if its in the control bucket,it cant leak.
when I moved my pump from the CB,I ended up putting it inside a 20 gallon tote,with nothing in it but the pump,that way if it leaked again,atleast I would have to put up new drywall,again.

I loved these systems years ago,thought they were sci-ency,but after using them for a couple of years,they wore me down,when they work its awesome,but when 1 plant has issues,they ALL do,1 plant develops root rot,they all get it. nothing worse than spending months on something,and it kick off.

not sure where you are at, but a buddy of mine built a 16 site system,using the square ones,he acquired them from restaurants,vegetable oil comes in them,steam clean and used for like 3 years now,he loves to tinker,and has been a water grower for 20 years,but even he,has lost all 16 at a time

 

[Papageno]

Hey I found a good vid on you tube that shows why people get confused and call Undercurrent systems RDWC. This is an RDWC but looks very similar to an undercurrent system. This is not sucking the water through the bottom generating and increasing vortex, rather recirculating it back to the top. In fact according to the voice in the video there is no pumping happening to the return, just let gravity do the work. For that system you can use small return tubes and a submersible pump. This is a good way to do recirculating but again they are doing a hybrid recirculating plus DWC because you have to be out of your mind not to put an airstone in each site. That is why it is RDWC. Come to think of it this may have been what you were actually asking about...but again for a little extra effort you can do the Cadillac of systems (Undercurrent DWC) assuming you can handle the noise.

And I would add that the way nutes get absorbed between these 2 different methods are very different so I wouldn't want to give advice on doing one for the other. Again Undercurrents use about 1/4 the nutes in ppm strength then DWC. But you may have to keep adding because I don't think in the end you use less. Just the concentration can be reduced a lot. The way it saves you on nutes is you are less likely to get out of balance and have over concentrations when you are feeding less concentration overall. So less waste when you dump. I have read it is much harder to get out of balance and cause nute burn in Undercurrent systems and I think that is why.

Also undercurrent has a bit of a back up. As long as the main water pump is going you probably get enough oxygen in the water to keep things from dying. So if the air pump goes out you can fix it before a catastrophe. Same goes the other way. If the water pump dies as long as your levels are correct the air stones should keep them going it just turns into a DWC system for a few hours.

The above design in the video if the main water pump fails there may not be enough left in the site to keep it alive long.


And one last thing...when I watched that video it automatically forwarded me onto the next one which was an Undercurrent DWC...that was called an RDWC. LOL

 

[Bayouboy]

With gh micro,grow and bloom you ahould keep it around 500ppm in veg and no more than 750patient in bloom

 

[go4snypr]

Also what you need to realize about ppm is that peoples meters are calibrated different. A meter calibrated with a .5 conversion reads different than a meter at .7 conversion. For example, what we are truly measuring is the conductivity of the water (EC). A meter that has been calibrated with a .5 conversion means that the EC of the water will be 1.0 when you reach 500 ppm. A meter at .7 conversion will read an EC of 1.0 at 700 ppm. so when talking ppm, you need to know what your meter is calibrated to as well as the person your discussing your ppm with. I run flora series as well and I run and ec of 1.0 in veg but keep it under 1.5 in flower. on a .5 conversion scale this is 500ppm in veg and 750 ppm in flower. on a .7 conversion, this is 700 ppm in veg and 1000 ppm in flower.

 

[Swedge]

Where do you guys fit the watrr pump?

I always thought it pumped water from the resevoir then drains back to the reservoir from the buckets but a lot of pics I've seen the water pump is places in the return between the buckets and the resevoir?
If so how are the feed lines connected?