Hello Grass City. After a long time of growing in soil, I've decided to give hydroponics a shot. I've done my research and it seems that a lot of DWC setups are using the same reservoir for growing and holding water. My question is, if I have an external reservoir dedicated to water/nutes that constantly pumps fresh water into the growing reservoir, can I have the air pump stones in the holding reservoir or do they have to be in the growing reservoir?
I will be using 3 18 gallon 9 inch high trays with recycled DWC. I am just wondering if I have to put air stones feeds into all of them.
Yes, each container holding plant will need airstones, once the root mass forms an aerated control res wont be able to keep up, the more oxygen the better, i run 5 gallon buckets and have 2x 4 inch airstones in each bucket
Thanks for the info. I think as an experiment I will put a varying amount of airstones in each one with none in the top tank. This should give me an insight as to just how much air I need to diffuse into the water I guess. Do I need them in the holding reservoir too? I just want to find out the optimal condition for the plants and watt usage.
Pretty awesome RDWC + Kratky + Aeroponics hybrid you got there! How crucial is the fogger? Does it make humidity hard to deal with?
Water temp is important, colder water carries more oxygen .. I am using a aeroponic systems , normally my DWC water runs 3 to 5 degrees higher then inside tent temp. I believe the pump making heat is why the water temp is higher then tent temp. I am making a chiller for my aeroponic system using of a refrigerator/freezer . I have a 30 gallon res feeding two 5x5 plastic 8 foot long fence posts . I have 3 plants per fence posts each fence posts can hold up to 4 to 5 gallons of water. Ideal water temp is 65 degrees because it holds the most oxygen . Inside the fence posts I normally have low water level and 100% humidity. The roots love oxygen and don't like light .
Think of your plants as fish. They want dissolved oxygen in the water and they can breathe under water. Likewise, with a fish, they will suffocate without dissolved oxygen, but however it gets to the water is solely up to you the grower. You can use air pumps and stones, water pumps with a waterfall action, water pumps with venturis, or electrolysis which is cheap on power and increases D.O more than venturis and stones with out raising the water temp like submerged pumps and stones do. Water chillers? Lol. Control your room temps and you won't need them. It is important to control night temps! 70-80 day and 60-70 night and you don't need chillers. Also water EC has an effect on DO and why lower ppm works well with dwc, it's only because water with less ppm holds more o2, just like cold water can, but less ppm works better than cold water especially considering cold water hinders bacteria growth, yes, but also hinders beneficial bacteria growth, that's why you don't want to go too cold with a chiller, also plant roots assimilate nutes faster in warm water so the colder water actually slows uptake. So with DWC, nutrient uptake is not the same as just monitoring your ppm and ph in your tank, and also why so many fail at it. But to more simply answer your question, you need the water under a current to only have the oxygenator in the reservoir so that water with the DO constantly touches the roots. Just having a res that keep things topped off with the D.O water wouldn't be enough.
If you look at my build plans, I don't use a submersible pump so as not to heat my reservoir and I use a peltier system and a thermostat to control the reservoir temp's further. My inline pump would be constantly circulating fresh D.O. water throughout the system and fall 3 separate times. My real question here is do the bubbles from the air pumps play a vital role for the roots or is it enough to enrich the water with oxygen.
Plants roots can't absorb air from the air or from air bubbles, they have no breathing pores but only work through osmosis. They're like fish, they can only absorb or use the air when it's in the water. Water cycles for soil grows are to deter bacteria from growing and not needed to add air to roots, that's why dwc works and other hydroponic mediums that you water multiple times. The air bubbles only serve to keep nutrients stirred and add dissolved oxygen to the water, the o2 can only be used when it's in the water and why you don't water ebb or soil gardens with stagnant water. Some people only use a waterfall method since it's all you need. Some people prefer both for a piece of mind. If you're asking what you need then you don't need air stones. If you're asking what to use then that is up to you, they each have flaws and benefits. Plant roots don't like turbulence, but neither does the bad bacteria that would adhere to the roots..and neither would the good bacteria. Lol. That's why you don't want too much air because the roots prefer not so turbulent water. You will have to find what works best for you. If you're just starting then I would recommend playing it safe with adding stones.
I cannot control the water temp inside my tent . I can control the air temp inside my tent to a constant 77 degrees. The water temp will go above 80 to 83 degrees . From my research Cannabis roots don't like any thing above 80 degrees . This is why I am making a chiller .. I don't want to exceed maximum water temp nor do I wish to go under the minimum temp that the roots like . But I have to keep the water temp with in those limits . I have no issues with keeping the water temp 70 degrees , the book I says 65 degrees is optimum . I don't see any other way besides making a chiller . I want to go traveling ……. I want to be able to leave for a week and not worry about my plants .. This is why I put in a 30 gallon tank , all I need is a 10 degree drop in water temp …. Fuck that took way to much focus , I got to roll a joint up.
Humidity was never a problem, EXCEPT, when the dew point is crossed, then I would get condensation pools under the plumbing. Running @ 64degF seems to be "problem free". The "fogger" is crucial.
What I've done is used a 90w peltier plate that is sinked to a copper coil that runs through the water in my reservoir and heat sinked on the other side with a cooling fan attached. Just remember refrigeration methods use a lot of electricity and create heat byproduct so you have to factor that into how you cool your water without heating your grow area. This has worked great for the drip reservoir on my soil system for years. My RDWC is going to be used for SoG using specific strains and phenotype bred for short, fat colas, straight to flower from clones and should be fine with cooler LED lighting at 900 μmol considering the lack of canopy depth. My setup uses a single inline water pump and a single air pump along with gravity to circulate and dissolve oxygen into the water and will accommodate up to 180 plants. PS. Im also using long, shallow tanks made of plexiglass painted black, sprayed with a thin layer of insulation foam, then painted white. The greater surface area should attribute to higher rates of dissolved oxygen, since that is what the air stone bubbles do..... oh..and the lids are just made of aluminum white sheet metal from the hardware store. Last question, can I just drip early on instead of relying on a mister or fogger nozzle until the size roots reach the nute water since i already have the equip?
For years? I don't know what you are using for nutrients, but most if not all result in a caustic soup that will eat enamel and the copper is toast. However, if you say you have no problem and been using it for years...........
I'm not running nute solution through copper pipe like this guy I'm using a copper coil chiller thats been coated with a corrosive resistant fluoropolymer. It's made for this.....
Good luck with your grow. FYI I was not circulating the soup through copper. I was using the copper for air delivery and the soup just did a # on it.