Welcome to the joys of building a pond. I have the Savio compact skimmer (because of it's size). I used a 2" bulkhead fitting in the bottom of the skimmer in that space between the filters and the back of the skimmer. I use a small threaded filter in this bulkhead fitting in the skimmer--just in case small fish came through the skimmer I don't want them in the pump. From the bulkhead I have a short piece about 3" of ABS, then a 90 to bring the pipe up again before going into the pump house. My skimmer and pipework is only about 18" away from the pump. 2" ball valve then a wye as joins the line from my sc. My valves are Ipex valves (given to me by a friend) so have quick disconnects for the pump. I glued the fitting that comes with the skimmer for a submersible pump into the skimmer. The one problem I have with my new pump is that I can no longer run skimmer only when shutting down the sc for water changes. The skimmer draws down too much and the pump wasn't getting enough water. So that might have to be something you calculate for in sizing your pump. In my case I would have to be drawing water from another source-perhaps a midline point but don't have space for any more prefilters before the pump. I also don't have my bd plumbed into the skimmer--someone else will have to advise you on this and draw down issues. If you do a search on this site there are instructions for installing the Tetra bd. If you rock the bottom of your pond there really isn't much point in the bd as it just won't work. The knife valve is to shut off the flow to the pump and or sc for maintenance. Ball valves are usually used to control the flow of the water. Leaf trap/priming pot even if external pump is in ground is a good idea. I didn't have one and found out the hard way when filter floss got wrapped around the pump. If I had a leaf basket it would have got caught in there. Also the Savio waterfall filters are expensive. A skippy type filter would give you more filtration at about 1/3rd the cost.

Ok, that makes sense. I forgot that every time it turns back on it would continue pumping. duh. The bottom drain is an Aqua Art retro fit bottom drain with 3" opening. It is connected to a black flexible tubing that is really hard (almost w/ a metal coil in it?). It is reduced from 3" to 2" and then runs back to the pump. I had a Sequence pump but that thing sucked (not literally, unfortunately). I had to have it repaired 2x and it was NOT cheap to begin with! It lasted 2 yrs. BOOOO. When it last gave up the ghost, it was 1.5 months ago. I found a hayward 1.5 HP super pump on craiglist for $150. The pond was w/o a functioning BD for about a month. Here is where it all goes downhill. lol So the previous pump was connected to the hose in from the BD and hose out to the bead filter by the black hoses that were connected with a black screw-on style of fitting. They simply did NOT come off, no matter what. The new pump had smaller openings and so the old fittings wouldn't work. We had to cut off the "screw" ends and use compression fittings instead (the black squishy sleeves w/ two metal bands that you screw to tighten). The first day that we turned the pump on and were messing w/ it, the same top fitting popped off b/c it wasn't seated properly (the hose hit me in the head, almost knocked me out from the pressure...lol...bruise on my forehead for 2 wks!). Because of that, I was paranoid and was actually shutting it off at night...just in case something went wrong. (I know, this is a long story lol) Saturday during the day, we saw that the pump was emptying faster than the water could come into the basket and we realized the BD was partially clogged and decided to get in the pond and get it freed up. DH jumped in and pulled it up...cleared it out and then set it up on two large pieces of flagstone so it wasn't directly on the bottom of the pond. (Note: had he not done this, when the disaster happened, it would've drained the ENTIRE pond. Truly a lifesaving decision for the fish that lived in the remaining 6" of water b/c of that flagstone!) Anyhoo, everything was riproaring along at 100mph again and I was checking the basket frequently...not much there. That night was the ONE night I didn't unplug it overnight...I forgot. Small debris plugged up the basket, increasing the pull of the pump, which started moving around the hose on the top of the pump. It was moving enough to pull the compression fitting off and it popped the hose off. The water simply geysered out of the top of the pump until the pond was almost completely empty. SOOOOO...way more than you asked but I have known you long enough to know that you like a clear picture, MIke! LOL I"m hoping that makes the error of my ways clear enough! At this time I am only running the BD during the day and am trying to find screw-on fittings to replace the existing compression fittings. Additionally, I have bungee'd the BD to a crate so it is a foot off the floor of the pond. I have also been partaking of some retail therapy and have a little mass of baby koi in the pond right now. They just came up and started eating food this morning and I literally screamed with delight LOL! I'm not sure how these water bobbermcthingie's work but I *think* the external pump is close enough that if it truly does have a 20' cord, I can put it in the body of the pond and run the cord back to where the pump is. Need to get to the store today and get one to rig it!

The frog isn't necessarily doomed - you'd be amazed at the freeze tolerance of most temperate-ranging anurans and caudates - there are many papers coming out showing how hardy these animals are. Bullfrogs are one of the most successful anurans out there and its for a reason - they are ridiculously adapatable and robust animals. Another thing to consider - bullfrogs have had their numbers be unnaturally increased by human encroachment - they are one of the few subsidized amphibian species out there (subsized species are those whose numbers are denser in areas of human inhabitation or as a result of human influence than they would be in a more natural environment - good examples of this are raccoons, skunks, and opossums) - if one dies, there will be plenty more to take its place. ~Mike

Well people say all kinds of stuff on the internet - no filter is possible I suppose but if you have fish you really should have one - both to filter poop, debris, fish food, etc. out of the water.... AND to provide surface for your beneficial bacteria. If you havent already done so pls read up on biofilters and the nitrification cycle which changes ammonia (from fish poop/decomposing organic matter) to nitrite to nitrate. The first two are highly toxic to fish, nitrate is what your plants will need to live on. Look into external filters of some sort since your pond will be very small - if you want to diy there is a "mini-me" skippy filter, also other similar you can buy already made. Yes there are ways to have a water garden and/or a stream at the TOP of your waterfall be your filter - that actually would be a very effective more natural-looking way of doing it and maybe thats what you have in mind? The plants growing in and among your filter media would utilize the nitrate in the water from the fish - in that sense the plants and the other media (whether lava rock, bioballs or whatever) would be acting as your filtration . Re pump size - I'd get a slightly bigger pump , maybe 150 gph (because once you add in tubing to take it up to waterfall its going the flow will be lessened). You might even go higher gph depending on the height and length of the waterfall and the tubing (there are charts where you can look this up and figure it out.) Last but not least, no more than THREE GOLDFISH. Those tiny fish will grow to 6-10 inch long within a few yrs and 30-50 gallons per goldfish is the recommended minimum. Have heard that rosey red minnows are good for small ponds too - if you want more fish. They are short lived naturally unlike goldies which live 10-20 yrs under good conditions. No koi - instead you might want to go a pond store for goldies - there are some bred now for ponds which are beautiful with bright markings and long fins. Thats all I can think of - my first pond was about your size, so Im trying to think of what I wished Id known then. Im sorry to say I lost some goldfish at the beginning because some idiot at the garden center kept insisting I didnt need filtration, just let it "balance out" he said... meanwhile the pond kept getting muckier and muckier. Yes you do need some sort of filtration, whether a formal product you buy or make, or informal system of plants/rocks. Spoze it could work if you just net or vacuum out the debris and have some system of doing frequent water change, or of trickling water in and out. With that small a pond its doable, but I cant help but think if you have a pump, why not do the filter as well and make it easier on yourself.