Idea for keeping reservoir temps cool

My rez temps are way too high, and I do not want to invest in a chiller just yet. I have heard about the frozen water bottle technique, but I worry about shocking the roots with direct coldness. So I had the idea today to get a big cooler and place my buckets in the cooler. Then fill the cooler with as much ice as I can. It will take me a few days to get the cooler but this sounds like a great idea to me. What do y'all think? Also, I was thinking of making some sort of top for the cooler for better insulation, but of course the top will need big holes for the buckets. Any ideas on how to rig this up? Would a basic piece of plywood, after sizing it for the cooler and making holes for the buckets, work? I know wood probably isn't the best insulator, but I am thinking it will be better than nothing. I can't think of any other material to use for top that I will be able to make holes in. Can you?

Just use ice jugs. If your water is to high it melts fast. And sorry but your idea won't work. Think of this what keeps soda/beer colder longer in a cooler. Just ice with drain pulled or the ice sitting in water around the cans? The water. Just add jugs of ice as needed. Not over do it.

Get a cooler and fill it with ice water. Put a pump in the cooler that circulates the ice cold water through a stainless steel coil (wort chiller). Put the coil in your rez.

You could put the pump on a thermostat so your rez water doesn't get too cold. 64-68F is perfect.

I found 25' S.S. wort chiller coils at nybrewsupply.com for about $43 each.


Putting ice jugs in and out of your rez and freezer is an excellent way to contaminate your rez with pathogens.

I've done that before but without any top, works pretty well. Just make sure the water level in the cooler is high enough to be effective. If you do put a cover on, styrofoam would be a better insulator than wood. It won't get warped and moldy if it gets wet, and its already white, so no need to paint or attach mylar/panda like with wood.

If/when you decide to look at chillers, look into the DIY dehumidifier method. Just built one myself the other day, cost me $50 for a dehu on CL, $50 for a wort chiller, and about a half hour of my time. And now I have a 'chiller' that cools way more efficiently than a $5-800 chiller. You can do it cheaper if you find a dehu that has SS coils, mine has copper so I need to use a wort chiller.

K.I.S.S. ice bottles are cheap and work.

Makes me think of that episode of Trailer Park Boys called "High Definition Piss Jugs". God I love that show.......

one better than the ice bottles is these disposable plastic freezer storage containers, fill them with RO and freeze them overnight and they pop out like a big ice cube. I just drop the cube in the res (igloo cooler) and it's done, no shit on the bottle to clean up and no worry about that contamination mentioned above.

dbkick said:

one better than the ice bottles is these disposable plastic freezer storage containers, fill them with RO and freeze them overnight and they pop out like a big ice cube. I just drop the cube in the res (igloo cooler) and it's done, no shit on the bottle to clean up and no worry about that contamination mentioned above.

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Yo thats a good idea... Shit I used to use those 5 gal igloo water coolers as my bucket in DWC... Lots of ways to cool your res on the cheap you just have to think or come ask some mofos on RIU ...

dbkick said:

one better than the ice bottles is these disposable plastic freezer storage containers, fill them with RO and freeze them overnight and they pop out like a big ice cube. I just drop the cube in the res (igloo cooler) and it's done, no shit on the bottle to clean up and no worry about that contamination mentioned above.

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Too much of this will dilute your rez, works in a pinch though.

facestabber said:

Too much of this will dilute your rez, works in a pinch though.

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in my case it means adding like a 1.5 liter chunk of ice into a 20 gallon or better insulated res so that's not much of an issue. with a 5 gallon bucket maybe.still we add water in between res changes no matter what the size don't we?

that's 1.5 liters of ice every other day, hell I'm adding gallons of water per day.next thing you know(depending on where you're located) we'll have to be preheating water. I love winter.

facestabber said:

Get a cooler and fill it with ice water. Put a pump in the cooler that circulates the ice cold water through a stainless steel coil (wort chiller). Put the coil in your rez.

You could put the pump on a thermostat so your rez water doesn't get too cold. 64-68F is perfect.

I found 25' S.S. wort chiller coils at nybrewsupply.com for about $43 each.


Putting ice jugs in and out of your rez and freezer is an excellent way to contaminate your rez with pathogens.

Click to expand...

Thats where I got my wort actually. 50' though, more surface area means more heat transfer. Plus, I plan on dual-purposing it when I get my brew setup goin, and rate of cooling matters alot more with that than this hobby.

And a'boot pathogens, I never thought of that before but I'd assume they wouldn't be alive very long in a freezer. Thoughts?

dbkick said:

in my case it means adding like a 1.5 liter chunk of ice into a 20 gallon or better insulated res so that's not much of an issue. with a 5 gallon bucket maybe.still we add water in between res changes no matter what the size don't we?

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No, I'm pretty good at mixing my nutes in a manner that the plants use them at the same rate they use the water so ppm stays stable. Sweet equilibrium.
Keep doing what works for you though, that's all that really matters.

How much are chillers? I was just wondering about making one out of an old window a/c by cutting the evaporator lines and reconnecting with flexible hose then placing the evaporator in the rez and extending the thermostat into the rez as well. Just disconnect the evaporator fan. I think I'd try to find the smallest one I could. The unit could just sit in the same room and dump its heat in there (which shouldn't be much and hopefully there is some kind of room cooling) or it could be put in a window or special hole. Of course this would take some special tools and skills or the hiring/bartering of someone so it's not a DIY for everyone.

depends on how big and if you buy it new , what brand. all that shit. diy chillers, not the route I'd take.

Ok I got 2 more ideas, 1 that I actually want to make moves on... putting the air pumps in a mini fridge/freezer? Where does the pump actually get the air from, is there just a little intake hole on it? Would I have to worry about the power cord being cold/humid? This just involves drilling little holes in the fridge, 1 for the power cord and 1 for each air line? Hmmmm but to fit the actual plug part through I would have to drill a pretty big hole..... you think I could just close the door on the power cord and just drill small holes for the airlines? About how much would this actually drop temps in a 5 gallon bucket? I saw somebody claim 5 degrees but I am not sure how much water he was chilling. Anybody know whatsup with this? I am aware that I should just get a chiller but I can get a mini fridge for free right now. Waiting until first harvest to upgrade on a few things.

My second, more ridiculous idea is pretty interesting lol.... The other day when I was doing a reservoir change/cleaning, I premixed my nute/h2o2 solution in individual gallon water jugs. Then I put the gallon jugs in the freezer for a bit to cool them down. I took them out after a little bit then filled up my buckets, but I accidentally left an extra one in there. Came back a few hours later and it was frozen solid. I know it is highly recommended against, but does anybody actually still use regular ice cubes to cool their water? What if I just took the jug of frozen nutrient/h2o2/RO and cut off the plastic jug. You're left with an ice cube of nutrients! Pretty cool idea. There is no way that I am really gonna try it, I just thought it was a cool idea that I haven't seen before. Is there a way to get the nutrient cube to attach/sink to the bottom of the bucket to avoid direct contact w the roots? I think the peeps who are using ice/ice packs already should give this a go. Hmmmm I am just picturing in my head some really high-tech DWC buckets..... special for cannabis growing with a bunch of different compartments/screens/places to add certain things like ice..............

Has anyone tried a used water cooler?

Like I have said. In hot temps all I do is 1 unopened gallon jug of water in the freezer and a frozen one in the 55gallon res. This keeps me under 78 all day long. 1 jug lasts 1 day and the other is freezing. Unless your a large grow a chiller just to cool a small res is just silly. If your going to spend for a chiller might just look at water cooling the whole room. Will cost more to buy but less in the end.

StoopidLungs said:

Ok I got 2 more ideas, 1 that I actually want to make moves on... putting the air pumps in a mini fridge/freezer? Where does the pump actually get the air from, is there just a little intake hole on it? Would I have to worry about the power cord being cold/humid? This just involves drilling little holes in the fridge, 1 for the power cord and 1 for each air line? Hmmmm but to fit the actual plug part through I would have to drill a pretty big hole..... you think I could just close the door on the power cord and just drill small holes for the airlines? About how much would this actually drop temps in a 5 gallon bucket? I saw somebody claim 5 degrees but I am not sure how much water he was chilling. Anybody know whatsup with this? I am aware that I should just get a chiller but I can get a mini fridge for free right now. Waiting until first harvest to upgrade on a few things.

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Man if you're willing to go through that much trouble and expense, why do it to pump slightly cooler air through the water? You're going to spend a ton of money on the electricity to run that fridge nonstop(air pumps produce heat as they run, meaning the fridge has to constantly counteract it instead of food which gets cold and stays cold), and youre going to lower your water temps maybe 2*F. And you still haven't addressed the larger heat issue for your water: ambient air temp from lights. You would be way better off spending the time/money on a chiller. Or if your up for the DIY as you suggest, the humidifier mod I mentioned can be done for $50 and provides WAY more effective cooling than that fridge idea, in the right place(the water itself).

Hell, even keeping the entire grow area at 70* would be cheaper than running a fridge all day, and it would actually work...

Or, suck it up and swap frozen bottles every day.

I disagree about chillers being silly even for small setups. Running a water cooled room turns a $50-500 chiller investment into a $2-5000 project after including enough ice boxes, pumps, the much larger chiller, and all the misc fittings, piping, controllers, etc for it.

Im guessing the last part was at me. After all I've read I'm guessing it 1-4 plants. So that's why I said it's silly.