How To Insulate A 35 Gallon Reservoir

[Delps8]

The grow is in a 2' x 4' tent in an unheated garage in SoCal. I'll be using a small oil heater to warm the tent and, if needed, will run the water chiller to cool the res (a 35 gallon res that uses 28 gallons of nutrient water for two really happy plants).

Here in the PRC, the lowest cost for electricity is 23 cents per KW so I'd rather insulate the res than pay to watch the the res chiller vs tent heater death match.

What's the best way to insulate the res?

 

[013]

Soil grower here so I don’t grow hydro but just watch temps on anything that rests on or touches the concrete. An indoor or covered concrete slab stays at around 55 degrees all year long with only a degree or two of variation from winter to summer since the slab is in contact with moist soil - this can give your plant or root zone cold feet. Use sheet foam and a wood pallet to elevate your plants and grow up off the slab but of course this can be used as home made chiller for your res...

 

[Delps8]

"55 degrees all year long with only a degree or two of variation from winter to summer since the slab is in contact with moist soil - this can give your plant or root zone cold feet."
I've got to insulate the bottom of the res but for a different reason. The geniuses who built the house did a lousy job installing the pipes from the water heater so a good part of the two car garage has a "heated floor". The tent is < 10' from the water heater so the floor temp is just over 70º.
So, yup, I agree 100% — get the res off the floor and put some insulation under it. Just a sheet of foam insulation? That would be dead simple.
The other piece of the puzzle is insulating the sides and top. My thinking - is there any value in insulating the res and, if so, how should it be insulated?
I realize that this is "in the weeds" level thinking, pardon the pun, but I know that someone out there has dealt with this issue.

 

[Yrock]

"55 degrees all year long with only a degree or two of variation from winter to summer since the slab is in contact with moist soil - this can give your plant or root zone cold feet."
I've got to insulate the bottom of the res but for a different reason. The geniuses who built the house did a lousy job installing the pipes from the water heater so a good part of the two car garage has a "heated floor". The tent is < 10' from the water heater so the floor temp is just over 70º.
So, yup, I agree 100% — get the res off the floor and put some insulation under it. Just a sheet of foam insulation? That would be dead simple.
The other piece of the puzzle is insulating the sides and top. My thinking - is there any value in insulating the res and, if so, how should it be insulated?
I realize that this is "in the weeds" level thinking, pardon the pun, but I know that someone out there has dealt with this issue.

you can just use an ice chest it's already insulated just drill a couple holes

 

[Delps8]

you can just use an ice chest it's already insulated just drill a couple holes

Yrock:

Good idea and very timely.

I checked some of the name brand coolers and it looks like I’d have to go to a 150 quart model. That’s a beast of a cooler and the outside dimensions would make it a tight fit in the ten.

That got me thinking - why not just build my own? It could be something as simple as four pieces of plywood and some insulation tacked on the inside. It’s not load-bearing so it would just need to fit around the res with enough room for insulation. Seems pretty straightforward, eh?

Thanks for the suggestion.

 

[Michael Hunt]

Keep in mind insulation works both ways. Does wonders trapping those nice cool temps in your res but will also trap the warmth from the water returning to your res from the plant sites. Did some experimenting since we JUST insulated our res and added a chiller about a week later. We were doing ice bottles before the chiller came onto the scene.

What we've learned was that the ice bottles melted fastest in the uninsulated res (obviously) and seemed to warm back up at a moderate rate but would level off depending on the air temp in our garage. Then we insulated the res after about a week of bottling without insulation. With it, the bottles melted a lot slower which was expected. But once they melted, the temps actually seemed to rise faster and further than in the un-insulated set up. AND, it held the heat a whole lot longer when air temps in the garage would drop at night. Making us replace the bottles just as often as the uninsulated res.

Unfortunately if your running hydro in a non air conditioned environment, a chiller might be your only real viable solution to keeping those temps stable and happy. They really don't run all that much and ours draws less amps than our light and fan combined.

 

[Delps8]

Michael:

"Keep in mind insulation works both ways.”
No question about that.

" water returning to your res from the plant sites.”
No sites. It’s a 35 gallon res in 2' x 4’ tent. The res holds 25 to 28 gallons. My notes from 2017 read 25 but I’ve got other notes that indicate 28. I’ll know in a few weeks when these kids go in the pool.

The hoses from/to the chiller are uninsulated but I can deal with that pretty easily.

"What we've learned was that the ice bottles melted fastest in the uninsulated res (obviously) and seemed to warm back up at a moderate rate but would level off depending on the air temp in our garage. Then we insulated the res after about a week of bottling without insulation. With it, the bottles melted a lot slower which was expected. But once they melted, the temps actually seemed to rise faster and further than in the un-insulated set up. AND, it held the heat a whole lot longer when air temps in the garage would drop at night. Making us replace the bottles just as often as the uninsulated res.”
The rates of change at non-0’ish temps should be linear, right? If the temps are rising “further”, where did the extra energy come from? There’s got to be something different between the two modes.

"Unfortunately if your running hydro in a non air conditioned environment, a chiller might be your only real viable solution to keeping those temps stable and happy. They really don't run all that much and ours draws less amps than our light and fan combined.
I tried the ice bottle route first time ‘round (summer of 2017) and decided it wasn’t for me so I bought an ActiveAqua 1/10hp unit and it worked like a charm. The temps were high enough that I bought a portable A/C unit to keep the tent temps in check. It worked well.

I’ve had a five gallon bucket in the res for a month. It’s only got 1 gallon ± in it and since I’ve put the seedlings in the tent and fired up the LED, the temp of the water has risen to 72º. The air temps are up a bit in the garage because we’ve had some 70’ish weather I suspect that the primary driver is the elevated temps in the tent due to the Kind running 24/day.

Last weekend, I built a riser for the res so it’s not longer sitting on a 73º floor but I’ll still have a res that being chilled to 68º in a room where I’m raising the temps. My goal is to raise the leaf surface temperature. Per a few articles, LED’s don't raise the LST very much so the trick is to raise the ambient temp. That’s where the temperature differential will come in — an ambient temp of 85º (a WAG that’s what's needed to get an LST of 75º) and a chiller temp of 68º gives a 20º differential.

 

[Michael Hunt]

Michael:

"Keep in mind insulation works both ways.”
No question about that.

" water returning to your res from the plant sites.”
No sites. It’s a 35 gallon res in 2' x 4’ tent. The res holds 25 to 28 gallons. My notes from 2017 read 25 but I’ve got other notes that indicate 28. I’ll know in a few weeks when these kids go in the pool.

The hoses from/to the chiller are uninsulated but I can deal with that pretty easily.

"What we've learned was that the ice bottles melted fastest in the uninsulated res (obviously) and seemed to warm back up at a moderate rate but would level off depending on the air temp in our garage. Then we insulated the res after about a week of bottling without insulation. With it, the bottles melted a lot slower which was expected. But once they melted, the temps actually seemed to rise faster and further than in the un-insulated set up. AND, it held the heat a whole lot longer when air temps in the garage would drop at night. Making us replace the bottles just as often as the uninsulated res.”
The rates of change at non-0’ish temps should be linear, right? If the temps are rising “further”, where did the extra energy come from? There’s got to be something different between the two modes.

"Unfortunately if your running hydro in a non air conditioned environment, a chiller might be your only real viable solution to keeping those temps stable and happy. They really don't run all that much and ours draws less amps than our light and fan combined.
I tried the ice bottle route first time ‘round (summer of 2017) and decided it wasn’t for me so I bought an ActiveAqua 1/10hp unit and it worked like a charm. The temps were high enough that I bought a portable A/C unit to keep the tent temps in check. It worked well.

I’ve had a five gallon bucket in the res for a month. It’s only got 1 gallon ± in it and since I’ve put the seedlings in the tent and fired up the LED, the temp of the water has risen to 72º. The air temps are up a bit in the garage because we’ve had some 70’ish weather I suspect that the primary driver is the elevated temps in the tent due to the Kind running 24/day.

Last weekend, I built a riser for the res so it’s not longer sitting on a 73º floor but I’ll still have a res that being chilled to 68º in a room where I’m raising the temps. My goal is to raise the leaf surface temperature. Per a few articles, LED’s don't raise the LST very much so the trick is to raise the ambient temp. That’s where the temperature differential will come in — an ambient temp of 85º (a WAG that’s what's needed to get an LST of 75º) and a chiller temp of 68º gives a 20º differential.

I see what you’re talking about now and have a better picture of what you’re working with

Just realized the actual insulation was never mentioned. We use that mylar coated bubble wrap you can get by the roll at most home centers. Between that stuff and the chiller, you’ll have the most consistent temperature’d res on the block

 

[Jeremy6232]

I use an ice chest for my clones but i also use a chiller to get it to the temps i desire. Then pump from chest into wort chiller in my main rez to keep temps for all locations using just one chiller. The ice chest is great though.

 

[Delps8]

Jeremy - that’s a nice setup. Chiller cools the water and warms the tent - neat idea.

I’m not resolved on doing nothing vs an ice chest (I’d need the 150 Qt size) vs building my own. The seedlings died so I’ve got extra time to figure it out.

 

[Delps8]

I see what you’re talking about now and have a better picture of what you’re working with

Just realized the actual insulation was never mentioned. We use that mylar coated bubble wrap you can get by the roll at most home centers. Between that stuff and the chiller, you’ll have the most consistent temperature’d res on the block

Michael:

Agreed. And that stuff is pretty easy to work with.