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jasonpatterson 04-30-2011 07:15 PM

3 gallon cookie jar
I have used this cookie jar a number of times as an aquarium of sorts, scooping up a bunch of pond muck and watching all the critters that live in it grow, but I finally decided to make a proper tank of it recently, here is the result.

It's a 3 gallon glass jar, approximately 16" high by 12" diameter. It is warm enough now that I was able to remove my heater; I don't plan on replacing that, as the guppies won't be in there when it gets cool again. I've got an aquaclear 10 powerhead in there right now with a sponge on the intake so that there is a current in the jar.

For lighting I drilled out the inner 1 1/8" of a 1 1/4" aluminum rod for a heat sink and mounted a 6500K 3 LED star with Cree XP-Gs inside the recess. I picked this particular configuration because it runs at 9v and I happened to have a 9v 1A transformer lying around. When I tested the transformer (after ordering, of course) I found out that the transformer was actually putting out 12.5V. Bought a 'universal' type AC-DC transformer and set it to 9V, 600mA and that is doing a great job of powering the light. The initial heat sink was inadequate so I added a small finned heat sink that I had to the back of it. The combination works well, especially in the humid environment that I've got it, though the light is a bit closer to the water than I care for now. I was going to paint the LED/star with polyurethane to seal it against the water it was sure to encounter, but from another thread on here I got the idea to paint it with clear fingernail polish. Found out the hard way that the waterproofing worked when I dropped it into the water while it was turned on.

The tank also requires an airstone, both for cooling the light and for aeration. With the close fitting lid on and the light running, there wouldn't be any good way for fresh air to get to the water, except through the small notch I cut in the edge of the lid for wires/tubes. I'm also using DIY CO2 on this tank, hopefully I'll be upgrading that to canned in the future.

Ultimately it will hold only RCS and snails, but at the moment there are also a bunch of guppy fry in there as well, and a few ghost shrimp. As far as plants, I've got ludwigia repens, something that was labeled as dwarf hairgrass (though who knows?) and a mystery plant. The driftwood is the root bulb of a forsythia bush that was uprooted about a year ago. I boiled it for several hours then kept it in an 8 gallon cooler that I filled with boiling water each day for 2 weeks before it stopped leaching.

The substrate is soil that I dug out of the creek in my back yard. (No fish or plants were disturbed in the digging of the dirt.) I allowed it to soak for a week or so, mixing it regularly. I then dried it, pulverized it into dust, then baked the dust to kill off any cysts/spores that may have taken the ride. Anything that can survive 2 hours in a 350 degree oven deserves to infest my fish tank. I used 1/2" of that topped with 3/4" of small gravel (3 - 5mm size.)

The picture on this page isn't the best, because of the positioning of the tank and myself (it's on my computer desk) I cannot see any cords, hoses, pumps, or filter sponge when I look at it, just the tank and some bubbles coming up in the back. The driftwood also looks much cooler. I'll try and get a better shot in the near future.

houstonhobby 04-30-2011 07:38 PM

I like this project a lot.

oscarsx 04-30-2011 08:58 PM

shoooot, that's dope man.. good looking cookie jar.

hydrophyte 04-30-2011 11:59 PM

That is really cool. I really like this kind of setup a lot and I have been putting together more of them.

And what a cool LED DIY that you put together.

jasonpatterson 05-01-2011 12:38 AM

Thanks for all of the compliments. I took a couple more pictures of the tank and a few details of the lid/light for anyone who is interested.

This view is much closer to how the tank is actually viewed. I've got the room lights off so that the shimmer from the surface/LED interaction is more noticeable. It's fairly pronounced. You can also see how strongly a spotlight effect the light is giving this close to the water's surface. I wasn't really looking for that, and I'm a bit concerned that taller plants are going to lean toward the center after the light. It does get a fair amount of sunlight though, so this might not be as big an issue as I fear.

A closeup of the interior with a better view of the driftwood and stones at the bottom. My daughters have named the stones, rather than the fish or shrimp, Rocko and Rocky.

For anyone who is interested, in order to have the lid sit flush against the jar with air lines and electrical cords in place, I had to notch it a bit. This can be done with a rotary tool (Dremel or similar) and diamond tipped bits (fairly cheap to buy if you can find them.) I cut the jar by immersing the spot in a cake pan filled with water and taking my time. It was surprisingly quick work for such thick glass. I also had to drill a hole at the top of the handle for a screw, and I made a recessed area for a washer to rest. This was done with the rotary tool as well.

A detail of the light. If I had it to do over again, I'd have started with a 1.5" diameter bar. As it was I wasn't expecting to succeed and was just having a go at it before paying a machine shop to do it right. I eyeballed the center so it's off a bit, but only by about 1/32", so I'm far from upset with the outcome. The first drill was 1 1/8" then I went to a 1" bit for the second stage. My original plan was to cut a circle of acrylic to fit the opening so that it would be protected from water, but the LEDs generate enough heat that I decided against it. With later modifications (adding the second heatsink to the top and cutting slots in the walls of the tube portion of the housing, I might be able to go back to that plan. I'd like to, as it would make cleanup much simpler. Right now the LED is exposed to the water and can get some pretty yucky gunk on it from time to time. (fish poop got up there somehow at one point and was cooked onto the light...)

psalm18.2 05-01-2011 01:30 AM

That is so creative.

hydrophyte 05-01-2011 02:58 AM

This would make such a cool manufactured product, but it would be tricky to deal with the potential liability issues.

TwoStrokeKing 05-01-2011 07:55 AM

Really nice jar!!

ashes2ashes 05-01-2011 10:58 AM

Very cool! :)

xmas_one 05-01-2011 01:36 PM

Where did you get the jar, its really neat!

JCoxRocks 05-01-2011 01:45 PM

This tank is sooooooo cool! I actually dreamt about it last night. I dreamt that I saw it in an old house I used to live in. Such a really neat tank and setup.


Quentin 05-01-2011 08:52 PM

Nice work.

matt12 05-01-2011 10:18 PM

looks cool!! btw your mystery plant is Lobelia cardinalis 'Small Form'

jasonpatterson 05-01-2011 10:59 PM


Originally Posted by xmas_one (Post 1375203)
Where did you get the jar, its really neat!

I got it at Target, either in the cooking section or their vases; I bought it five or six years ago though. I used it for a couple of years to hold pond water in my classroom then it sat in my basement for a few after we moved. I dug it out again when I needed a home for the guppy babies and decided to make a decent aquarium out of it. The rest of the setup followed from the need to keep the lid on the thing and the light firmly attached to the tank because my cat is the devil.


Originally Posted by JCoxRocks (Post 1375211)
This tank is sooooooo cool! I actually dreamt about it last night. I dreamt that I saw it in an old house I used to live in. Such a really neat tank and setup.


I m in ur dreemz, designin ur fish tankz. :icon_mrgr


Originally Posted by matt12 (Post 1375578)
looks cool!! btw your mystery plant is Lobelia cardinalis 'Small Form'

Thanks much. I tried the plant profiles here but didn't find it, didn't think to check APC.

I really like the look of the guppy fry in this thing, I might try to find some very very small schooling fish to replace them with once they're ready to come out. I want this to be primarily a shrimp tank, but it's height leaves a fair amount of unused room for them, even with the wood/plants to climb around on.

The shrimp have claimed a hole in the back of the wood as their domain. It's maybe 1/2" diameter and 1" deep and there are always at least 5 shrimp crammed in there.

I'm also thinking of cutting another slot in each of the fins of my light and seeing if I can bend them outward, kind of like a flower. It should improve the heat sink and let the light spread out a little earlier so that there is less of a spotlight effect. I might also be able to cover the LEDs a bit more effectively with that in place.

jasonpatterson 05-02-2011 12:55 AM

Happened to be at Target tonight and they had a similar jar still in stock in the cooking section. A 2 gallon version for $15.

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