Rdwc questions

Howdy? So I have a basic idea of how things work, doing my research now before I start my grow and I have a couple questions I can't seem to find an answer to, so here they are:

1. Do you guys that rdwc use a ph doser to keep your ph stable in between res changes?

2. This is a total newb question but how do you do your res changes?
2 a. The question I have is that it seems to me that you want to change out all the nutes and water in the system, so for the sake of conversation let's say you have 4, 4 gallon buckets, and a 20 gallon res, total of 36 gallons in all. I've seen on some systems there is spigot in the res, so that's self explanatory, but what about the buckets that your plants are in? Do you physically take the plants out or use a pump to drain the buckets the plants are actually sitting in? I know there is a return line and pump to the res, but my head keeps telling me that it probably wouldn't be a good idea to run those pumps to the point they are dry, is that logic sound or am I thinking to much?

3. I've seen vids on microbial tea, is the benefit of using this the same as introducing mycorrhizae? If it is not, at what point do you use a microbial tea? Do you make your tea and then add nutes to that tea?

Thanks for reading and any response you can offer
 
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rkymtnman

Well-Known Member
i built a 4 site RDWC and loved my results but you do have to stay on top of it because things can go wrong very fast

i didn't use a doser. i checked pH 2x a day so i could dose manually if needed

i used shower drains in the bottoms of all my tubs (2 in room, 1 control out of room) which led to a drain with valve that would dump into a floor drain next to my hot water heater. a wet dry shop vac also works to empty tubs/buckets too.

i always went sterile vs microbes. dutchmaster zone and a chiller kept the nasties away for me.

good luck with it! growth is unbelievable but you will need to babysit it. my only drawback with it was constant monitoring daily.
 

ttystikk

Well-Known Member
I don't use a pH doser, either. My RDWC plant site tubs are all 27 gallons, for the specific purpose of ensuring that the nutes don't go off too far in one day.

I don't sterilize, I run a chiller to keep my water in the sixties where the ladies like it. I also don't flush during a run, I just add more nutes as I top off.
 

GIJonas

Well-Known Member
I only change twice during a run and all 16 sites are connected to a 50 gal res so draining the res drains all sites. Easy, I don't see how your setup would require draining sites individually?
 

rkymtnman

Well-Known Member
I only change twice during a run and all 16 sites are connected to a 50 gal res so draining the res drains all sites. Easy, I don't see how your setup would require draining sites individually?
i think what he was getting at was what about the water that is left in the buckets that is below the drain/fill pipes. that's why i used shower drains at the bottoms of my tubs vs drain/fill lines that go into the sides of the buckets. maybe i'm reading too much into his post??
 

GIJonas

Well-Known Member
There should only be like 5-10% water remaing. No need to change that thoroughly during a run unless your anal about it. My setup might leave 5 gallons unchanged out of 100+
 
i think what he was getting at was what about the water that is left in the buckets that is below the drain/fill pipes. that's why i used shower drains at the bottoms of my tubs vs drain/fill lines that go into the sides of the buckets. maybe i'm reading too much into his post??

That it's rkymtnman. I've been looking at rdwc systems online to get an idea of a build, but that question popped in my head about what to do with the water that's left over and not able to drain because it's below a drain or maybe the drain is placed in a spot where some note solution would be left over.

The stuff I've read and seen just says res change, but it doesn't say how thorough the change needs to be, I just figured al of it needs to be changed out. Thanks for your help!
 
i didn't use a doser. i checked pH 2x a day so i could dose manually if needed

i always went sterile vs microbes. dutchmaster zone and a chiller kept the nasties away for me.
So I guess the best thing to do about ph would be to monitor it and make adjustments as necessary, does the daily fluctuation have any negative impact on the plant?

Is the microbial tea used to cut down on things that may negatively impact the root mass? Diseases, etc? I was under the impression that if you want to go rdwc that a chiller is an important piece of gear to keep your water temps down, helping you get more O2 into your water, along with helping your plants keep the "nasties," away.

Thank you for your reply.
 

rkymtnman

Well-Known Member
So I guess the best thing to do about ph would be to monitor it and make adjustments as necessary, does the daily fluctuation have any negative impact on the plant?

Is the microbial tea used to cut down on things that may negatively impact the root mass? Diseases, etc? I was under the impression that if you want to go rdwc that a chiller is an important piece of gear to keep your water temps down, helping you get more O2 into your water, along with helping your plants keep the "nasties," away.

Thank you for your reply.
your ultimate goal in dwc is to have your res level drop, your EC/ppm to stay the same and your pH to rise slightly daily. what that means is the plants are feeding/drinking just the right amount. if EC goes up, it's too much nutes. if Ec drops, it's not enough nutes.

so I would set my pH on day 1 at 5.5 and let it rise until it hits 6.1. then lower again to 5.5 and repeat. some nutes are better absorbed at different pHs.

the tea is to keep healthy bacteria alive and well inyour res. i never liked that concept. i always wanted nothing to live in the res, just white healthy roots. either way isfine. the zone i use is just chlorine and copper.

and a chiller is required too. 68F is best temp to keep. most dissolved oxygen.
 
your ultimate goal in dwc is to have your res level drop, your EC/ppm to stay the same and your pH to rise slightly daily. what that means is the plants are feeding/drinking just the right amount. if EC goes up, it's too much nutes. if Ec drops, it's not enough nutes.

so I would set my pH on day 1 at 5.5 and let it rise until it hits 6.1. then lower again to 5.5 and repeat. some nutes are better absorbed at different pHs.

the tea is to keep healthy bacteria alive and well inyour res. i never liked that concept. i always wanted nothing to live in the res, just white healthy roots. either way isfine. the zone i use is just chlorine and copper.

and a chiller is required too. 68F is best temp to keep. most dissolved oxygen.
Awesome thank you.
 
So another question. Do you think a system that is 36 gallons or close to that is too small? I know bigger systems are safer in the sense that fluctuations aren't as bad.

Is there a minimum size you guys prefer? I'm not looking for yield at this time, prefer quality.

Thank you
 

rkymtnman

Well-Known Member
you could build something like mine out of 27 gal totes for 4 plants. they ended up about 5 ft tall and WAY outgrew the lights i had at the time. with the proper lights, i would have had enough for almost a whole year. the top stuff was quality but the bottom stuff was popcorn fluff shit.
 
you could build something like mine out of 27 gal totes for 4 plants. they ended up about 5 ft tall and WAY outgrew the lights i had at the time. with the proper lights, i would have had enough for almost a whole year. the top stuff was quality but the bottom stuff was popcorn fluff shit.

Holy mackerel! 5ft would be to big for me. I'll be in an enclosed space so I'll be looking for stout strains, or I'll be limited to like 7 days in veg tops depending on how much stretch I'd be looking at. Ideally I'd want my plants to finish at about 4 ft. I like the idea of training them so I could keep most of my nugs at the top of the canopy for max light. SCROG is what I'm liking. Or maybe like a SOG grow, but limited to like 6 plants with a slightly longer veg time. Any thoughts or opinions?
 

rkymtnman

Well-Known Member
how big is your space? do you have a plant count to worry about?

i think scrog is a great way to grow and maximize canopy light coverage.

i personally don't do it. my grows now are about 3 weeks from seed (about 5 inches tall) and then go to 12/12. my plants end uparound 3 ft when done.

with a scrog, your veg time is really how long it takes them to kinda fill up the screen and then flip to 12/12. so it's really strain dependent
 
how big is your space? do you have a plant count to worry about?

i think scrog is a great way to grow and maximize canopy light coverage.

i personally don't do it. my grows now are about 3 weeks from seed (about 5 inches tall) and then go to 12/12. my plants end uparound 3 ft when done.

with a scrog, your veg time is really how long it takes them to kinda fill up the screen and then flip to 12/12. so it's really strain dependent
Cool, I'm limited to 6 plants unfortunately, might be able to go 12, but that's not certain yet. My space will be about 7 ft long x 6ft tall x 4 ft deep. My concern is heat, I was thinking about building a grow box/shed. Basically a grow tent made of wood.

Most of the designs I've seen mount the lights on the inside, for convenience I'd think. I'm thinking of mounting the lights on the outside, if that makes sense. That way I won't have such a tough time in dealing with heat, in the ceiling of the box I'm thinking about cutting windows or something so just the face of the light hood sits on glass.

I've read some stuff about the lights loosing some slight potency going through glass, but what I'd gain in heat management is worth the loss of 5% or so from the lights imo.

I'm thinking this will help in heat management in the box and the actual res, also I figure the ac unit and chiller won't have to work as hard if the lights wee mounted on the inside.

And I'm also thinking that CO2 enrichment would be more efficient in a sealed box, and more economical.
 
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