Hello -
My husband and I received two small pond shells (no pumps etc). One was used, the other new. I saw a picture of two preformed ponds butted up together, but no instructions on if you use the same pump, if you can waterfall from one to the other. Each time I look at pond pump parts, I am lost as to what I will need to purchase. Please let me know if there is an instruction guide on how to connect to ponds.
Thanks.

Hi Dawn!

There are really no limits on what you can do with water gardens. You just have to remember that water will go down the gravity well, and will penetrate any escape route open to it. Joining two pre-formed pond shells is difficult, since they are designed to be used as "stand-alone" systems. Their edges are level when the pond is set in level, and an overflow situation (which all streams and waterfalls are!) will be generally spread all the way around the perimeter. If you are looking for a more complex array and are going to dig a hole anyway, flexible 44 mil pond liner is usually easier to work with.

If you want to use what you got and have them joined, they'll need to be on two levels, and you'll need to cut a spillway out of the lip of one of them. Simplest will be a widish rectangular chunk, with a flat rock set into it, supported inside the upper pond with other rocks and sealed with pond liner and large quantities of aquarium caulk or 100% silicone tub and tile sealant. The edge of the flat rock protrudes out over the edge and overhangs the lower pond. A good idea would be to "stack" the two ponds, with the smaller one on top, so the cutout overhangs the body of the lower pond. A small submersible pump in the lower pond with its outlet hose hidden by plants and mulch and emptying into the upper pond will give you a small and attractive water feature, suitable for aquatic plants and maybe a few goldfish in the lower pond.

This system will be high-maintenance, since the pump will tend to clog with debris fairly often and the bottom will fill with sludge fairly quickly. If it receives direct sun, you'll get algae, and the only aeration and biofiltration will come from your falls (inefficient) and your plants(seasonal and diurnal). These shallow systems are also very prone to predation, and are often referred to as "McRaccoons". Do not grow attached to any critters introduced. The tend to be named "Lunch" by the nocturnal visitors. For a good introduction on pond design for beginners, see Mike White's articles on pond design on our website.

(Answer courtesy Bob Passovoy)