I buy all of my 5 gallon buckets from home depot. The Lowes ones are the same. Try a search on Google?

Thats an issue of negative pressure. try using a larger tube out the bottom. smaller diameter pipes will often not be large enough for the air to 'fight' its way back past the water in the pipe to even out the pressure. something about it not being a strong enough force to overpower the surface tension the water forms with the walls of the pipe.
Thats how I fixed the problem with my automatic cat waterer...ererer?!? i went from a tiny air pump hose pipe to 1/2" pvc. the gatorade bottle never collapsed again.

but to actually answer your question; try usplastics.com

grizzman, both answers were great. Thanks for posting them.

Not sure if I understand the question, but it seems to me that all you have to do is drill a small hole at the top of the bucket to vent it.

Why don't you run a float valve into your emily's garden then you can use whatever resevoir you want and it will fill the emily's garden to wherever you install the float.

I looked up the emily's garden. I didn't realize that is actually the name of the set-up when I first read the question. I thought maybe emily was a daughter or something.

So it seems that what is happening is that the water fills the reservoir before air can get back into the bucket because the walls of the bucket aren't sturdy enough to withstand the POSITIVE pressure of the surrounding atmosphere. The air right outside the bucket is given the opportunity to stabilize the pressure by collapsing the walls and you want the air in the reservoir to have that opportunity via traveling up the tube. Couldn't a bigger tube simply mean a faster collapse? It sounds like there isn't enough of a drop in pressure in the bucket to cause the air in the reservoir to move up the tube. A sturdier wall will allow for more time to get a further drop in pressure and force the pressure to equalize, which means the air outside will find a way into the bucket via the path of least resistance. Right now the path of least resistance is a flimsy wall. With a sturdier wall the path of least resistance is the tube.

you're over thinking it joe. a larger pipe will allow the pressure to stabilize more quickly by allowing air 'in' more quickly.
The only other factor at play is the amount of head in the system. the higher the reservoir is above the outlet the greater the pressure differential. keep it as low to the full level as possible with a 3/4 diameter pipe and you shouldn't have a problem. I only recommend the larger pipe because that has fixed my similar problem in the past. the walls of the bucket should be plenty strong enough to with stand the pressure differential.

Grizzman, I don't think I am overthinking it. I think you are thinking this problem through with a regular 5 gallon bucket in mind. A regular 5 gallon bucket for paint is highly unlikely to collapse like tbaleno's is collapsing under the described circumstances. Instead, it would cause a vacuum and not let the water out. I've not seen Home Depot's buckets, but Menard's (another big box store) buckets are practically translucent because they are so thin. I wouldn't be surprised if the manufacturer for both companies is the same. With flimsy enough walls, the walls will collapse before air entering the tube moves far enough. Once the walls are collapsed the pressure is stabilized as the air in the bucket is compressed. Unless the air coming in the tube is forced air (unlikely), then it won't make it up the tube if the bucket has begun collapsing. At least not enough to stop further collapse the next watering. As the collapse starts it will put positive pressure on the tube and not allow air to enter from there. You are absolutely right that a larger tube will speed up stabilization, but it first speeds up destabilization. It is then just a matter of whether the bucket walls can withstand the initial destabilization or not. Just judging from what was originally written, that the bucket is collapsing already, the walls are very thin and I have those Menard's buckets in mind. Maybe I'm incorrect and tbaleno has thicker buckets than Menards provides.

Another thing that could be contributing to the collapse is the length of the tube. If it is too long AND the wall of the bucket is too thin, then that will also cause collapse before air can travel up the tube. Personally, I would be inclined to go with both, a sturdier bucket and a wider diameter tube.

The wall of the bucket is pretty much as described. Pretty thin.

Here are things I'm going to try.

1) lower the bucket to about level with the plants.
2) shorten the hose
3) if all else fails get a float valve.

It seems to me you're thinking about this backwards.

If that bucket leaks air at all (air can leak into it) you'll run the risk of flooding your Emily's Garden.

Instead, how about pumping water from the bucket to the garden, and fitting the garden with an overflow outlet that drains back into the bucket?

Just plumb a line into the side of the garden at the high-water mark and down through the top of the bucket. That way, if the garden starts to get too full, it just overflows back into the bucket.

You could even run both pumps off the same timer. And in this case the point of failure results in the Emily's Garden working as it always does, whereas the method you're trying can fail and overfill it.

That's not a bad idea. Can you link me to a pump and help me set it up? I kind of understand what you are saying, but may need some hand holding.

As for overflowing the garden. It has happened. TWICE. The emily's garden has a tube you use to tell what the water level is. If you don't cap it the overflow will be set at where ever the top of that tube is. I replaced that short tube with a longer one to make it easier to change the water. The tube I use is about 5' long and arcs at a point where there is a clip to hold the top of the original tube. The water went up over that arch and through the rest of the tube and all over my table.

I could probably just use that tube to dump back into my reservoir. I'm thinking I only need a pump. I'm using 3/8" tube from my bucket now, so if I get a pump with 3/8" fittings I should be all set.

Could you point me in the right direction with a link?

You'd be best off with whatever cheap little thing you can find... there's no real demand for big gph or head or anything so some little cheap aquarium pump or whatever would do just fine for you.

Any pet store or Walmart or something is bound to have something that would work. Just make sure it's submersible.

I'm not sure I understand the problem, but if it were my problem, I'd poke a small hole in the lid of the bucket to allow atmospheric pressure to equalize from the outside; preventing bucket-wall collapse.

Now, if you want MORE volume, do this simple trick: place another equal-size bucket next to the one the pump is in and "link" the two using an inverted PVC pipe of any size that has two elbows on one end making it into a "U" shape. Make sure the bottoms of the "U" are cut at an angle, so they won't suck to the bottom of the buckets when it is in place.

Fill the "U" tube with water and hold your thumbs over each end while you slide each end into an already-full bucket of water. One bucket is where your pump is and the other one is the new "reserve" bucket.

Make sure the drip system drains into the "reserve bucket" and nature will take care of the rest.

Hope this helps.

God bless.

:O)

The whole point of avoiding collapsing sides of the bucket is that, in the system he was employing, this would allow water to flow into the reservoir at an unregulated pace. Putting a hole in the lid would simply make that problem worse.

If you have a five gallon bucket suspended over a reservoir that has a hole in the lid and an open line to the reservoir you're simply pouring five gallons into the reservoir. You can do that without all the fancy stuff - just dump it in.

The object here is to use a bucket to increase the capacity of the reservoir by keeping it topped off any time the solution level drops below a certain point. That's where the sealed bucket would come in handy (though as I pointed out it's not necessarily an ideal method).

As far as the U tube method goes, wouldn't it be simpler to just connect two buckets with a hose that goes two a bulkhead fitting at the bottom of each bucket? That way you don't have to do anything fancy, you just pour water in and there's no worries about whether the tubing has a bubble in it or not. Or better yet, just use a larger container such as one of those massive rubbermaid bins or even a 55 gallon drum.

I would guess the original tube was collapsing from the vacuum drawn in the sealed 5 gallon bucket. If it was enough to collapse the bucket, it will collapse a tube that isn't designed for vacuum. Use a larger, flexible, kink/collapse resistant tubing.

I know I'm posting years afer this issue was brought up but the answer to your question is brutally obvious. A FLOAT VALVE is the solution to your problem. They're made specifically for this purpose, to keep reservoirs topped off at the level of your choosing.

Here is a link that might be useful: Active Aqua Float Valve w/Wing Nut