nouvellechef said:
I run fans 24/7 and De-humidifier is set it and forget it at 40% on top of a rez.
Me too - with CO2 as well. Regarding this original post - I think something else must have been causing the ph creep, a dehumidifier would only be capable of altering ph if you removed so much (over 50% more like 75%) of your reservior water without replacing it that you concentrated your nutes and locked out. They dont otherwise have the ability to alter ph in water, all they do is suck water out of the air.
Yes, just like an air conditioner, a dehumidifier is really a type of heat sink and causes heat as a byproduct of it functioning. A surprising ammount of it. I am working on mine regarding this. It blows all the heat out of a slotted area in the back via a heavy duty fan, I am trying to seal off the back, make basically a big funnel that narrows down to my vent duct size then I want to tap that exhaust into the outgoing duct and hopefully at least half the heat will end up outside not blowing around my growroom.
58F at night is too low if your days are that high - its dang low anyways but you have like a 30 degree F difference in your light and dark cycle. When the warm air cools the moisture in it (humidity) has to go somewhere. Its an elemental law of enviornmental physics. So it condenses. Usually in your buds. Resulting in molds, mildews, and *baaaaaad* budrot. During flowering Ed Rosenthal reccomends humidity "...at 50% - 55% and your mold problems will cease." (Ask Ed best of). You are too humid and are asking for budrot and molds. Fans help a lot, I run my vent fan with my CO2 so its complicated but before I had CO2 I ran the vent fan (a 10" vortex in 12" out) at a rate that could remove the air in the room in just about a minute. Thats overkill but budrot sucks.
Environmental fans (blowing on the plants) I leave on 24/7 for same reason plus bugs hate it.
I think your solution is to have the dehumidifier run at night and off during light period. This excess "waste" heat will keep the temp and humidity stable and higher - probably exactly what you need. Not waste at all - you get a two-for-one. One is the benefit of the right humidity range so you dont get rot. Two is the temp stability which results from the dehumidifier running so what most people view as a negative side effect (the heat) you actually benefit from - plus dont forget cannabis doesnt like the temperature to swing that large a range. You will see better growth and larger more compact flowers if you narrow the range down to 15 degrees (from the night low to the light high).
If "the purple" is all the rage for you a temp drop at the last few days of flowering to 55F (you are close) will cause a lot of strains to turn a purplish color to intense almost neon purple. Just a trick I use for friendly purple-heads who refuse the exact same strain as inferior and harsh and weak will jump up and down and rave about the SAME PLANT even if I harvested part while it was green then let it get its 55F purple color change. If anything it actually causes a reduction in THC from degredation to the thc glands becoming brittle and breaking the tops off leaving just the little stem part and losing the mushroom shaped blob at the tip. Just goes to show the power of the placebo effect as far as Im concerned, and the silly behavior you get when Snoop Dogg sings about weed being a purple color - all the sudden nothing but purple is "hip"
I hope this helps, contact me if you wish for any further help or for source data.
Al
