Dwc, A/c + Bubbler = Temperature Control?

[purklize]

I'm thinking about making the move to DWC for multiple reasons (faster growth, better control over pH and nutes without sitting in the bathroom till 8am flushing soil as my RO filter struggles to keep up, and the ability to seal the vessel to keep f'n root aphids out). The temperature in my tent usually hovers around 75-80F, but the air cranking out of my a/c is much cooler, usually 70F or cooler. I was thinking I could put the air pump in front of the a/c and run the lines into the tent to bubble the DWC, therefore keeping it nice and cool. Reasonable proposition?

 

Thanks.

[Green-Nubie]

Tent will need to be. 65 at night 72-75 lights on. If not water will warm up and root rot will thrive.

[Darkmatter]

Well it kind of depends on a few things too. How many plants do you want to grow in said DWC buckets? Just remember that you will have to wash buckets and change water every 2-3 weeks. When you have plants trained and tied down this get rather difficult.

 

After trying DCW I would never recommend it to someone with a high plant count, or someone that does not have an R/O system(I see that you do).

[purklize]

I was just thinking of doing a perpetual harvest with 4 plants flowering at any given time. One plant per 5 gallon bucket, 400w HPS. I don't think I'll be able to get the tent down into the mid 60s, not in the summer at least. The main reason I'm thinking DWC is because I have a lot of different strains and really don't want to have to dump any, or have any deal with non-ideal nutes to appease others (shared reservoir).

[Jipo]

Tent will need to be. 65 at night 72-75 lights on. If not water will warm up and root rot will thrive.

 

This is so wrong. While its not good to be much over 80 unless running co2, I run my room at 85 with 1500ppm co2 at all times. No root rot, no issues, you wont' see major heat issues until the mid to upper 90's. You will lose some size and yield if your in the 80's without co2, but while 70-75 is ideal, its not gonna kill anything if its above or below, remember people plants grow outside. temps outside get upwards of 100 here... bacteria can start flourishing in a res around 80* but water temps are always lower, unless your running a heavy pump you're fine.

[LongHairBri]

This is so wrong. While its not good to be much over 80 unless running co2, I run my room at 85 with 1500ppm co2 at all times. No root rot, no issues, you wont' see major heat issues until the mid to upper 90's. You will lose some size and yield if your in the 80's without co2, but while 70-75 is ideal, its not gonna kill anything if its above or below, remember people plants grow outside. temps outside get upwards of 100 here... bacteria can start flourishing in a res around 80* but water temps are always lower, unless your running a heavy pump you're fine.

AGREED

[Green-Nubie]

Info like the above comments is why people have so many issues with water..

 

Lets talk about dissolved oxygen ration and res temp. and how oxygen deprivation leads to pythium, combine that with a perfect breading temp of around 80 degrees..

"Most growers are familiar with the need to have some form of aeration in their nutrient solution - whether they be in a recirculating or a media based system. In DWC systems, this is often accomplished with the use of an air pump or by allowing the nutrient to fall back into the reservoir, thus introducing oxygen. However, the effect of temperature of the solution on the dissolved oxygen levels and on root respiration rates also needs to be taken into account. As the temperature of your nutrient solution increases, the ability of that solution to 'hold' dissolved oxygen decreases. For example, the oxygen content of a fully aerated solution at 10C (50 F) is about 13ppm, but as the solution warms up to 20 C (68 F) the ability of the liquid to 'hold' oxygen drops to 9 - 10ppm, by the time the solution has reached 30 C (86 F), then it's only 7ppm. "

____________________________________________________________________________________________________________

 

75-80 degree water temps is asking for problems.. and once they start they don't stop very easy.

"Perhaps one of the most common problems in hydroponic systems is the Pythium pathogen and what many growers don't realize is that Pythium being an 'opportunist' fungi, often takes advantage of plants which have been stressed by a combination of high temperatures and oxygen starvation in the root zone. Pythium is usually described as a 'secondary infection' meaning that the Pythium spores which are actually common in just about all hydroponic systems, don't actually attack the plant until it has been damaged in some way. Even very clean hydroponic systems and grow rooms which are isolated from the outdoor environment will have some Pythium present as these fungal spores are naturally present everywhere on a world wide scale - in the water, soil, vegetation, carried in the air and in dust, so it's difficult to eliminate the source of this disease. However, one way we can reduce the 'spore load' is to sterilize any water supply which may be contaminated with high levels of pythium --- water from dams, and streams should always be sterilized before use for this reason if Pythium is a problem. "

 

But dont take my advice i know nothing about growing in water..

Dr. Lynette Morgan

 

Nutrient Temperature: Oxygen and Pythium in Hydroponics

by Dr. Lynette Morgan

 

2001-09-01

 

The hydroponic nutrient solution is not just a mix of fertilizer salts and water, there are a number of organisms and compounds commonly found in our hydroponic systems that we need to be aware of. One of the most important of these is dissolved oxygen, which is vital for the health and strength of the root system as well as being necessary for nutrient uptake.

 

Most growers are familiar with the need to have some form of aeration in their nutrient solution - whether they be in a recirculating or a media based system. In NFT systems, this is often accomplished with the use of an air pump or by allowing the nutrient to fall back into the reservoir, thus introducing oxygen. However, the effect of temperature of the solution on the dissolved oxygen levels and on root respiration rates also needs to be taken into account. As the temperature of your nutrient solution increases, the ability of that solution to 'hold' dissolved oxygen decreases. For example, the oxygen content of a fully aerated solution at 10C (50 F) is about 13ppm, but as the solution warms up to 20 C (68 F) the ability of the liquid to 'hold' oxygen drops to 9 - 10ppm, by the time the solution has reached 30 C (86 F), then it's only 7ppm.

 

While this may not seem like a huge drop in the amount of dissolved oxygen, we have to remember that as the temperature of the root system warms, the rate of respiration of the root tissue also increases and more oxygen is required by the plant. For example, the respiration rate of the roots will double for each 10C rise in temperature up to 30C (86 F). So the situation can develop where the solution temperature increases from 20 - 30C (68 - 86 F) during the day, with a mature crop and a large root system, then the requirement for oxygen will double while the oxygen carrying capacity of the solution will drop by over 25%. This means that the dissolved oxygen in solution will be much more rapidly depleted and the plants can suffer from oxygen starvation for a period of time.

 

The symptoms of oxygen starvation which can occur in both NFT and media based systems can be difficult to pick up as they are very general signs. Media based plants are just as prone to oxygen starvation in hydroponic systems as those grown in solution culture, but here we must also take into account the 'air filled porosity' of the media used. This is simply how much air can permeate between the particles in the substrate and selection of a free draining media which won't break down will ensure that maximum aeration is going to reach the root zone. Injury from low (or no) oxygen in the root zone can take several forms and these will differ in severity between species. Often the first sign of inadequate oxygen supply to the roots is wilting of the plant during the warmest part of the day when temperature and light levels are highest. Insufficient oxygen reduces the permeability of roots to water and there will be the accumulation of toxins, thus both water and minerals cannot be absorbed in sufficient quantities to support plant growth particularly under stress conditions. This wilting is accompanied by slower rates of photosynthesis and carbohydrate transfer, so that over time, plant growth is reduced and yields will be affected. If oxygen starvation continues, mineral deficiencies will begin to show, roots will die back and plants will become stunted. Under continuing anaerobic conditions, plants produce a stress hormone - ethylene which accumulates in the roots and causes collapse of the root cells. Once root deterioratation caused by anaerobic conditions has begun, opportunist pathogens such as Pythium can easily take hold and rapidly destroy the plant.

 

Another more visible and longer term effect of oxygen starvation which also occurs in waterlogged crops is leaf 'epinasty'. Epinasty is a downward curvature of the plant leaves, resulting in plants which look wilted. If the oxygen starvation continues and is severe, then eventually leaf chlorosis yellowing, premature leaf and flower abscission will occur.

 

There are a number of things we can do to make sure our nutrient solution is carrying sufficient dissolved oxygen, and this is important when we consider that many of the root diseases encountered in hydroponics have occurred because the root system was damaged in some way, with anaerobic conditions being a major factor in many situations. The first most important factor to remember with oxygen is that the best way to introduce this gas into the nutrient is to have the solution fall back into the reservoir, and the greater the drop height, the better the aeration effect. Breaking the flow up into a fine shower also assists by introducing more air bubbles into the tank. Secondly, while nutrient EC does reduce the oxygen carrying capacity of the solution, the effect is very small and temperature has a much greater influence on oxygenation. Reducing excessive solution temperatures will ensure more oxygen can be held by the solution and the rate of respiration by the roots will be kept down to optimal levels. Thirdly, factors such as nutrient flow rate, channel width, length and slope have a large effect on oxygen levels- faster flow rates, greater slopes and shorter channel lengths all assist with prevention of oxygen starvation.

 

Perhaps one of the most common problems in hydroponic systems is the Pythium pathogen and what many growers don't realize is that Pythium being an 'opportunist' fungi, often takes advantage of plants which have been stressed by a combination of high temperatures and oxygen starvation in the root zone. Pythium is usually described as a 'secondary infection' meaning that the Pythium spores which are actually common in just about all hydroponic systems, don't actually attack the plant until it has been damaged in some way. Even very clean hydroponic systems and grow rooms which are isolated from the outdoor environment will have some Pythium present as these fungal spores are naturally present everywhere on a world wide scale - in the water, soil, vegetation, carried in the air and in dust, so it's difficult to eliminate the source of this disease. However, one way we can reduce the 'spore load' is to sterilize any water supply which may be contaminated with high levels of pythium --- water from dams, and streams should always be sterilized before use for this reason if Pythium is a problem.

 

Under the right environmental conditions, virtually every plant species is vulnerable to Pythium, which not only causes 'damping off' of seedlings but causes root and stem rot of older plants. Symptoms of Pythium on older plants are a wet rot, root systems will be browned, roots hollow and collapsed. Plants may appear to grow poorly and wilt for no apparent reason --- indicating that an examination of the root system when called for. Pythium has an optimum temperature range for infection of plants, which is generally between 20 - 30C (68 - 86 F), although infection can occur outside this range when damaged plant tissue is available for rapid colonisation by the pathogen. Low concentrations of Pythium that may not cause problems at lower temperatures will be disastrous at higher temperatures, particularly where the warmer conditions are associated with a lack of oxygen in the root zone and plant stress.

 

The best preventative measure against Pythium attack is a healthy, rapidly growing plant as this is an opportunist pathogen and will enter at the site of tissue injury or if the plants are overly succulent, weakened or stressed for some reason. Often root damage during the seedling stage as plants are introduced to the hydroponic system is a danger time for Pythium infection. Pythium is of greatest threat during the seed germination and seedling development stage when plants are most vulnerable to attack, and adequate control and elimination of the pathogen during this stage is the best preventative measure of Pythium control in hydroponic systems. Strong healthy plants will develop resistance to Pythium attack during the seedling stage and this will prevent problems at a later stage of growth.

 

Other preventative measures include the use of a well drained media, thorough disinfection of all equipment between crops (a strong hypochlorite solution --- bleach is the most effective), and control of pathogens during the seedling stages with a suitable fungicide, long before they are introducing into your hydroponic system. Occasionally a very high spore load, combined with excessive temperature will result in Pythium attacking even healthy plants, if this is the case, it is likely that there is an active source of spore production present and the system must be shut down and disinfected. Some growers have found the use of wetting agents and chlorination of the nutrient solution beneficial in limiting the damage caused by Pythium, however extreme care needs to be taken when using products such as calcium hypochlorite as to much active chlorine will kill sensitive plants. UV light, hydrogen peroxide and ozone have also been used to kill Pythium spores in the solution, however these can have major effects on some of the nutrient elements in solution and careful consideration should be given before using these methods. Sterilization of the water supply with these methods, before nutrient are added however, is effective at reducing or eliminating Pythium from the original water supply.

 

Therefore by ensuring your plants are healthy and stress free, you will not only get the highest growth rates possible, but also prevent problems such as Pythium infection occurring. The variables to remember with regard to the nutrient solution is that aeration is vital to maintain the dissolved oxygen levels, temperatures should be keep within an optimum range and Pythium is always present, but a healthy plant is the best measure of protection against a disease outbreak. About the oxygen requirement of plants when in flower...its not always the case that plants require more oxygen because they are in flower, a plants oxygen requirement is linked to the size of the root system, temperature and nutrient uptake rates, rather than the presence of flowering. Since plants such as tomatoes tend to have a rapidly developing root system at the time of flowering, it's important to maintain adequate oxygen levels. With tomatoes, the requirement of oxygen in the root zone increases gradually up until the time of maximum fruit load and rapid fruit expansion, where the high rates of nutrient uptake increase the oxygen requirement quite dramatically. On the other hand, if oxygen is deficient during flowering, then the flowers and subsequent fruit may drop off as a result, or they may be undersized and may fail to pollinate.

 

* * *

[purklize]

Interesting, I saw people claiming that anything above 70 meant doom for DWC. This is good to know. I can *definitely* keep temperatures below 80, and with bubbling air straight from the a/c I imagine I could keep it around 70.

[LongHairBri]

air is the key to success with ANY type of hydro set-up. get the best pump and largest air stones you can. MORE IS ALWAYS BETTER W/AIR.

 

I pump 8 l/m into 4" disk stones 24/7 with my AP100

[Jipo]

"Bunches of scientific information"

 

Come see my res temps sitting in the 70's without a sing of root rot or a discolored root... Granted each 5 gallon bucket has enough air going into it to aerate a 50 gallon aquarium, I haven't had a single root rot issue and I've had a few days in my room get almost to 90. Co2 may help with all this, Haven't ran that hot without co2 ever. Just because something can flourish under certain circumstances proves nothing. Mites flourish in dry hot areas, does every grow room with low humidity and higher temps have mites? Ideal conditions and survivable conditions are two different worlds.

 

Now in an ideal world I'd have my temps at 80 w/ co2, res temps under 70 and 10lb plants year round. But misinformation is spread like wildfire cuz some "scientist" made a statement, its just like the DEA says medical marijuana is still illegal, so every bodies going to get raided and go to jail...

[purklize]

Is it really loud bubbling that much air? I do have a dedicated room but I share a wall with a neighbor; I don't want anyone thinking Niagra Falls is in residential Ann Arbor.

 

I'm excited to do this. I'm planning on using neoprene disks through the plant's entire life cycle along with tanglefoot or vaseline, in order to seal it well enough to keep root aphids from getting back in.

[Guest Happy Guy]

Is it really loud bubbling that much air? I do have a dedicated room but I share a wall with a neighbor; I don't want anyone thinking Niagra Falls is in residential Ann Arbor.

 

I'm excited to do this. I'm planning on using neoprene disks through the plant's entire life cycle along with tanglefoot or vaseline, in order to seal it well enough to keep root aphids from getting back in.

The compressor is loud. You could build a sound proof box for it if you are concerned.

[Jipo]

Is it really loud bubbling that much air? I do have a dedicated room but I share a wall with a neighbor; I don't want anyone thinking Niagra Falls is in residential Ann Arbor.

 

I'm excited to do this. I'm planning on using neoprene disks through the plant's entire life cycle along with tanglefoot or vaseline, in order to seal it well enough to keep root aphids from getting back in.

 

The pumps i run are pretty loud but they're industrial pumps, the actual buckets are pretty well insulated not a ton of sound, a little fizz, but my inline fans are far louder, outside my house you can't hear a peep but inside my house it sounds like its gonna take flight, and get net pots and hydroton it'll prove way better support then neoprene discs, I can't imagine them holding up a budding plant without pushing through.

[purklize]

Ah, my fan is loud too, 400cfm, but within the realm of acceptable for me. Guess it might be alright then.

 

I was thinking of doing the net + hydroton thing with neoprene on top, actually... it is really important it's sealed. Root aphids are eating my bunny muffin alive in the flower room. I may have set their population back a lot recently but I'm sure they'll be back, from what I read they always come back. I used 2ml rosemary oil per gallon water with a dash of soap on each plant, rubbed vaseline all over the base of the stems, and dumped tons of diatomaceous earth on the tent floor... I don't see any of the bstards anymore. But again... I'm sure they'll be back.

[Jipo]

Ah, my fan is loud too, 400cfm, but within the realm of acceptable for me. Guess it might be alright then.

 

I was thinking of doing the net + hydroton thing with neoprene on top, actually... it is really important it's sealed. Root aphids are eating my bunny muffin alive in the flower room. I may have set their population back a lot recently but I'm sure they'll be back, from what I read they always come back. I used 2ml rosemary oil per gallon water with a dash of soap on each plant, rubbed vaseline all over the base of the stems, and dumped tons of diatomaceous earth on the tent floor... I don't see any of the bstards anymore. But again... I'm sure they'll be back.

 

They make nice little plastic net pot lids actually, have a little slit and a hole in them for the plant to go through. I believe they clip on top of the net pot.

[purklize]

Oh cool, I guess I could probably complete the seal with vaseline, as I planned with neoprene. Great, thanks guys, I really appreciate you taking the time to offer advice.

[Mike Sativa]

These are my roots in 80+ degree room. She even hit 88 a couple times and i never had a root rot problem.

 

 

i also agree with Jipo on this one.

[LongHairBri]

These are my roots in 80+ degree room. She even hit 88 a couple times and i never had a root rot problem.

 

 

i also agree with Jipo on this one.

thanks for posting, I didn't feel like taking proof pic's tonight. I've had a sip or two of my BHO/Kaluha! sent to lab, results soon

[Jipo]

That bho u gave me if freaking devastating!

[LongHairBri]

I had from 60 to 70 percent THC in the samples I had tested!! as a control I made a sample w/o the double boil, came out 10% LESS!!

[Mike Sativa]

LOL BHO/Kaluha ?

 

Umm, ill take a sixer !

[coreyz]

air is the key to success with ANY type of hydro set-up. get the best pump and largest air stones you can. MORE IS ALWAYS BETTER W/AIR.

 

I pump 8 l/m into 4" disk stones 24/7 with my AP100

 

 

 

Whats a Ap100 is that a air pump?

[Jipo]

Whats a Ap100 is that a air pump?

 

A very serious air pump.

 

Also Bri, I was reading some stuff the other day on a guy who makes BHO and after he double boils it, he puts it into a mason jar on a small tray and attaches a break bleeding pump to a mason jar lid and purges under extreme vacuum, looked interesting and extremely clever. Just food for thought if ya ever get bored and wanna craft a little something up

[LongHairBri]

A very serious air pump.

 

Also Bri, I was reading some stuff the other day on a guy who makes BHO and after he double boils it, he puts it into a mason jar on a small tray and attaches a break bleeding pump to a mason jar lid and purges under extreme vacuum, looked interesting and extremely clever. Just food for thought if ya ever get bored and wanna craft a little something up

I'm thinking THIS is my next step!My link. I think I'll use sprayer cans and a refrigerant pump. just need to find affordable stainless fittings and valves

[Jipo]

I'm thinking THIS is my next step!My link. I think I'll use sprayer cans and a refrigerant pump. just need to find affordable stainless fittings and valves

 

Wow I was talking about something more like this

 

Whatever that contraption you linked is looks pretty intense