The reservoir temperature poll to end all temperature polls

Discussion in 'Hydroponics / Aeroponics' started by Sureshot2, Jan 20, 2018.


What temperature do you run your chiller at (in Fahrenheit)?

  1. 58-62

  2. 60-64

  3. 64-68

  4. 68-72

  5. Other

Multiple votes are allowed.

    Sureshot2 Well-Known Member

    Since there is a lot of conflicting info, disinfo, misleading info or just plain bickering, let's hear from everyone on what they run their res at in this thread. I set it to allow two responses in the event that you let your temps drift or if they just vary. This is for people chilling their reservoirs only.

    I see a lot of people saying anything under 65f will slow growth a lot, and others saying under 55f slows growth. Others say you will get root rot above 72f and others above 65f. This likely confuses the shit out of new growers, so lets try to establish some good results here.

    If you are going to argue a point at least give a logical reason. Experiences on sterile res/bennys are welcome.

    I run mine at 60f in rdwc and have never experienced any slowed growth, and run hydroguard at 2ml/gal twice a week. I never have root rot issues with this regimen.

    Lordhooha Well-Known Member

    No chiller, here but my water stays at 68 to 70

    Lordhooha Well-Known Member

    Lol just seen for folks that chill only

    Terry385 Well-Known Member

    A: 62-68°F (17-20°C). Above 72°F (21°C) and dissolved oxygen (DO) dips too low. Below 60°F (16°C) and plants tend to slow their metabolism as they "think" the season is changing. Some growers use this to their advantage and reduce nutrient temperature towards the end of the flowering stage to aid in ripening.
    zypheruk likes this.

    Sureshot2 Well-Known Member

    I have read this before and I have to disagree with it. I have many times had my res temps around 58-59 with no ill affect, but I appreciate your input. I think if you have the ambient air temps still in the 70s-80's the plants can recognize that its not changing season and adapt to the cold roots temps. I think the real threshold for too cold is probably closer to 55 or below.
    zypheruk likes this.

    Rahz Well-Known Member Rollitup Advertiser

    DO content is somewhat linear while plant metabolism will look more like a bell curve generally cited as peaking at around 30C (86F) in soil. I've been unable so far to find reliable information on canna specific root zone temps in soil so I didn't bother trying to draw that information into the chart below but 68-72 is the general recommendation factoring in both DO levels and root metabolism.

    I don't have any hard data, but suspect water will support greater heat transfer than soil at field saturation, meaning optimal metabolism in water (DO aside) is likely somewhat lower than 86F (think aeroponics). This is likely why 78F is cited as a good temperature for propagation.


    Optimal temps for pythium (90% of hydroponic pathogen issues) are between 65-75F but it can cause problems in the range of 60-80F. While the optimal temp for pythium is 70, most beneficial microbes are going to thrive at temps in the mid-high 70s.

    60 degrees with a sterilization agent may be most effective at controlling all microbes. 65 degrees alone doesn't offer any protection as far as I can tell. 72-78 with an active healthy culture of beneficial microbes may be the most effective biological control. Microbes aside, conventional wisdom seems to suggest 70 is the best balance between DO content and plant metabolism... but whether that is true I don't know.

    zypheruk Well-Known Member

    17-18c here for res and totes in dwc.

    Victor6634 Well-Known Member

    65 -68F depending on what phase their in is what I run mine at
    Blue brother

    Blue brother Well-Known Member


    southernguy99 Active Member

    what I'd say is it really makes no difference what everyone else runs it at because the results are not going to be duplicated in another room unless there both exactly the the same and 100% controlled environment etc. water temp is a variable ,thats it , the same as environment. the roots and leaves communicate directly with each other, so unless the rooms are 100% the same water temp is 1 variable in the process and will be different for room to room. what the grower should be interested in, is what is the optimal water temp that they can achieve for their set up. taking to account there own variables like environment, root rot etc. from my experience in controlled rooms with optimal water , no root rot etc, optimal environment conditions, lighting, temps etc, optimal feed, the best water temps were 70-72 anything over that had an effect on growth in a negative way the higher we went the worse it got , the same anything under 70 had an effect on growth the lower we went the worse it got.
    Last edited: Feb 1, 2018

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