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Old 11-29-2015, 09:43 PM
GpsFrontier GpsFrontier is offline
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Join Date: Mar 2009
Location: Lake Havasu AZ.
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I did that the first year I started growing hydroponically and noticed when the air pump ran 24/7 I had a major headache with reservoir temps running the same as the temps outside which at times gets to the high 90's because air pump is pushing hot air into the air stone.
Is it possible that the heat was cumming from somewhere else? You even stated that insulating the reservoir on top had a big effect. Likely even from the reservoir sides and bottom, as well as the temperature differential as you run the water through the system. I know that common sense would dictate that if the air is warm going through the air pump, it will heat up the water. That should also work in reverse, if cool air is going through the air pump it should cool the water (which was my hope). But I did a test a few years back and the results showed no change in water temps at all.

I took small container that held about 3/4 of a gallon of water. I put the air pump in my freezer and closed the door with the plug and air line hanging out the bottom. The air going in the air pump isn't going to get much cooler than directly from the freezer. I took the temp of the water before the experiment witch was somewhere around room temp. I put the air stone in the water and plugged in the air pump. I let it run like this for at least an hour pumping frozen air through the air pump and stone in the water. With less than a gallon of water the temp should change very quickly, but after more than an hour the water temp didn't even change 1 degree.

I also grew some strawberry's last summer in a non-recirculating system. I used a 32 gallon Trash Can for the reservoir. I insulated this trash can well by warping 4 layers of bubble-wrap insulation around it and warping that with white duct tape for a tight fit. Then I made a lid for the trash can out of two layers of 2 inch thick Styrofoam insulation. I also set the trash can on a layer of high density Styrofoam insulation so heat couldn't radiate up through the bottom sitting on the ground.

Our daytime temps were were between 108 and 120 degrees. Our night time temps were over 100 degrees (even at 4-5 am). I would need to fill this reservoir about once a week to make sure it never run dry, it used about 2.5 gallons per day. When I filled it I added about 10, 1/2 gallon ice blocks (5 gallons of ice) so the water was ice cold. The water in this reservoir. would remain at least cool to the touch all week. There were a few times near the end of the week when there was only about 5-10 gallons of water left that I added a block or two more ice. But for the most part it stayed cool to the touch all week long.

I used a twin output air pump for 60 gallon aquariums in this reservoir, and let it run 24/7. Not so much for the dissolved oxygen, but mostly for the rising air bubbles to keep the nutrients mixed evenly and from settling at the bottom. But despite running the air pump 24/7 and with air temps between 100 degrees at night and 120 during the day. There didn't seem to be much if any affect on water temp from the air pump. Running it 24/7 with those kind of air temps, the water temp change should be very quickly noticeable, one day, two max. But like the cold air test, it just wasn't an issue.

Quote:
I will have to look into this during the winter months. I would prefer to get more of a mist onto the roots for 5 minutes instead of spraying them for 30 minutes every 2 hours during the daytime hours.
I got the idea from someone that built an aeroponic system using that spray method, let me know if I can help you with it. He told me how he built it, and he pressurized it to around 90 psi for a fine mist and small water droplet size. He used a cycle timer for short bursts, around 3 seconds every 5 minutes or so I think (it was 3-4 years ago I talked to him). I have been meaning to build a aeroponic system like it ever since. With such short bursts, even with so many of them, he didn't go through as much water as you would think. That's why I'm so interested in how much water your plants were drinking up using the aeroponic method.

P.S.
I always mark the inside of all my reservoirs. This way I will know exactly how much water to replace as the plants drink it up. That way the nutrient solution isn't to diluted or concentrated when I replace it. Knowing the volume of water I'm adding back also allows me to be able to average out how much water each plant is drinking daily.

Comparing different size plants isn't all that hard either. Just break it down to percentages. Like if a plants foliage is 25% bigger, I would expect it to drink 25% more water. Here is an example:

Example 1
Plant 2 is about 25% bigger than plant 1
plant 1- drinks 2 gallons of water per day
plant 2- drinks 2.5 gallons of water per day

Plant 2 is drinking 25% more water, but is also 25% bigger. Therefor I cam conclude that for it's size plant 1 is drinking the same amount of water as plant 2.

Example 2,
Plant-2 is 50% bigger than plant 1
plant 1- drinks 2 gallons of water per day
plant 2- drinks 3.5 gallons of water per day

In this example plant 2 is 50% bigger, but is drinking 75% more water than plant 1. Considering plant 2 is 50% bigger than plant 1, I would expect it to drink 50% more water as well. So 75% minus 50% (size difference) equals 25%. So I can conclude plant 2 is drinking 25% more water than plant 1 in an equal comparison, even though the plants are different sizes.

Anyhow that's how I do it.
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