Shelly, I have mated quite a few preformed ponds together and also added a fifty gallon drum onto the side of a preformed pond or two through the years. After cutting the desired size of area out with a jig saw/saber saw, I bolted the two sections together around the perimeter of the cut with 1/4" nuts and bolts to hold them securely. Prior to bolting them up tight I laid a bead of Plummers Goop between the two sections as a sealer. Using splicing tape, as suggested by taralynna, is also a good way to seal up the joints. Insead of buying it from a pond store, try going to a hardware store and ask for skylight/roof flashing, sealing tape. It is the same seaming tape used for EPDM pond liners, but is sold a lot cheaper as skylight/ roof flashing tape. You can get it double or single sided and it comes in a strip about five feet long. "Horton"

If you're planning to have someone dig the pond, lay the liner, and add a few tons of rocks, then the price you were quoted is probably an average cost. There are ways you can do it for less. When I put my pond in, the liner and equipment (skimmer, waterfall bio box, plumbing hoses, pvc glue, waterfall foam, and other assorted equipment, cost a grand total of $1,200.00. The catch? I dug the pond myself, got some friends and relataives to help me lay the liner in the hole, and did the plumbing work myself. It isn't hard. The rocks cost extra, but I ended up taking the rocks out anyway -- it looked great, but too much maintenance for my taste. I personally wouldn't use the aquascape system. I'm sure their equipment is probably good, but they dump a ton of rocks in there and their calculations are often way off the mark, leaving you with less water volume than promised. I also don't like the stair-step shelf rings that invite predators. If you want a liner pond and don't want to wield the shovel yourself, look into renting a mini excavator. They're fairly easy to operate, and you should have the job done in one day. The cost should not be much, compared to the price you were quoted for installing the pond. Or, if you know some teenage boys who would like to earn a few hundred bucks for some hard labor, ask them to dig it for you. I have a friend who hired her garden men to dig her pond, and they had it done in one afternoon. Some people are perfectly happy with their little preforms and stock tanks, though, so it's all in what you're looking for. For me, I like large koi, which cannot be placed in a small preform.

It can be evaporation. 2.5 ft of water can't evaporate over night. A pack of foxes drinking all the water over night. That would have to be a very large pack of maybe 500. Hyacinth could be if you maybe 10,000 that had been dried out for a couple of days. So those are not the reasons. It has to be in the waterfall as Johnkr said. Yes it could be an animal that blocks the water flow from the waterfall but if your pump pumps 500 gph then it would take that animal getting wet for at least 6 minutes. Yes it could happen but not likely. Yes it could be plants blocking the flow but the problem with this is that once the pond would empty again unless the plants were moved. So what else could it be? Now we have to look at the likely as maybe the likely. Since it only happens once in a while it has to be something happening once in awhile. One thing it could be if the winds picked up strong enough to blow the waterfall water off to the side where it leaks out. Unlikely but possible. Or it could be someone playing a joke on you. Unlikely but possible. If you could post a picture of the waterfall and pond the answer might become quite clear. Mike

Thank you Jaime for the pond liner and concrete bird bath. Good luck with your yard renovations.