What's a good design for bucket fill/emptying?

So I have 4 buckets in a tight room. They are just black buckets with no ports. It's working now because the plants are small, but what is a good way to set these up to dump and refill them when they are big? I attempted using spouts on the side but that proved problematic and slow and offered no way to easily refill. Is there a simple solution to this?

Someone once posted a hand operated siphon. I'm sure you could find one for ten bucks. It transfers liquid from one reservoir to another.
http://en.wikipedia.org/wiki/Siphon
http://www.amazon.com/K-Tool-International-KTI72250-Mult-Siphon/dp/B0015DQFMI

I personally, when i had 5 gal buckets i had hoses connecting to all of them and then one with a valve, then lead it to my bathtub open valve and bang drain

The shed is a bit elevated so I could probably just get a 1" tube and drawn it out to start the flow.

I use a small pump -mouse i think there called the type the sell with the basic nft kit well a they should fit straight to the hose , cut it to a decent lenght mtr or so less and drop pump in to pots that what i do, or have an spare bucket you can put your plant in while you change your res ,its no good if scrog..

Sounds like a siphon is the way to go. tubing is cheap, usually less than $.50 a foot. Between grows you may want to consider installing drain valves in the bottoms of your buckets.

It would be easy to dump the waste water under the shed but you still need to clean out the bucket.
An extra bucket is all you need to give the honeys an air bath in the process.

I find that the 12 quart sterilite totes with the white lids and clear bottoms for $3 to be better than a bucket.

The lids overhang so much as to not let any light in when growing in confined spaces. You also get six more inches of vertical space with a 3 gal tote vs. a 3.5 gal bucket. Checking water levels and water quailty at a glance is the way to go.

Siphon is slow unless your plants are elevated get a cheap bilge pump at Wally world takes me 1 minute