Hi Gloria,
You could probably look for a solar thing, but I'm not sure it work that well.
I'm thinking if you get alot of plants going, you might not even need a filter.
There's a post about solar aeration somewhere in the first couple of pages here. Check that out. I'm thinking of getting one, but I've heard the cheaper ones are useless. I'm thinking about getting a Sun-Jet 290M solar pump. One person on the forum has that one, and is happy with it.
How far are you from an electrical outlet (with a GFCI)?

Wind and solar come to mind, but my guess is neither of these would be cheap, or very practical. Without knowing exactly what it is about the location that prohibits electrical power, let me offer another alternative. I'm guessing you could find a small pump that would operate on 12 volt DC power. This would mean you could run the 12 v power to the pump with regular 14 gage lamp cord that wouldn't have to be buried or put in conduit. This would be the same kind of setup that powers those cheap low voltage lawn lights. If your pond is within 200 feet of 110 power and there is a place for the transformer, this might be a workable alternative.

I've always had good luck using lots of aquarium grasses-- from pet stores & fish stores -- Anarachis & any others they might have. I submerge the grasses & hold them down with a rock. If the water starts getting a lot of algae, just add more. I've always been able to keep clear water in small ponds & containers this way.
Good luck
Susan

I agree in that you really don't need filtering unless you have fish...or other messy, live critters.

Brenda

I agree, it depends on what you want. If you don't care about crystal clear water and have no fish, it can be done with lots of plants and some water changes, and patience.

I started out that way, and liked what I got, but then I got a couple goldfish to keep the skeeters down...then I wanted to SEE the fish...etc..etc. I have a pump and DIY skippy type filter now. And I still love my pond. The great thing about this hobby is it can be as big or little (complex or simple) as you want :)

Thank you All for the advice and suggestions. Am new to this type of gardening, but can feel an addiction already!!! Back of my mind keeps whispering ... "fish, fish, fish"!! So I guess no matter how new or experienced, one always wants MORE!!! ;0) Thanks again. Gloria

As long as you don't have large fish (goldies, koi) you don't need filtration. You do need some way to prevent mosquito larvae. A few mosquito fish, or regular and applications of BT, or mosquito "dunks". The plants will be fine. But you MUST keep up on the mosquito prevention.

hoovb: Are Mosquito Fish easy to care for? Can they swim fast enough to escape the raccoons? Where do I buy them ... is that the name they are sold by? TIA Gloria

Gloria, if you're already thinking bigger and better, be sure that the plans you have now include room for expansion if your budget can handle it :) Everything you don't have to totally re-do is a savings.

Gloria, try calling your local county's vector control or mosquito abatement district. I received mine free from there.

They may also go by the name Gambusia affinis, or just Gambusia.

Brenda

Right! I will have to rein myself in for awhile!! Think I will start out "small" ... just plants and mosquito dunks!!! At least until I get the hang of water gardening. Can I grow water lilies and lotus together or will each require a separate container because of the "bog" conditions for the lotus? I have ordered several water garden books and as soon as they arrive I'll not have to pester w/ so many questions! Thanks to all for the advice and encouragement. Gloria

Gloria.........please don't ever think your questions are pestering! That's what we all come here for......suggestions/help/opinions......so please, keep asking questions!
I've had a lotus in a container and a lily in a container in the same 100 gallon stocktank before. its a tight fit but possible.
But in your 300 gallon, you should do fine with a lotus and lily (in containers). The lily pads might collide with the lotus floaters, but that's not really a problem. The lotus, after they get their floaters, grow upright. Just be sure to put your lotus on the side of the stocktank where it won't shade the lower growing lilies.
I know several of us have talked about having a lotus bog, but lotus grow just fine in containers that are set down into a stocktank. The lily continer should go on the floor of the stocktank, whereas the lotus container should be on something like a milk crate, to bring it so that the surface of the container is about 4-6" below the water's surface.
Have fun!

catherinet: Many thanks for the suggestions. As always you are right on and very clear. Much appreciated. Gloria