We've had a koi pond for years and as our koi continue to grow ever-larger (over two feet long now), we've had to install additional mechanical and biological equipment to keep the pond clean and the fish healthy.

With two pumps, two biological filters, one mechanical filter, and one ultraviolet filter, it seems like something malfunctions and has to be replaced every year or so.  Sometimes it's possible to order the same model and then all we have to do is detach the broken piece of equipment and install the new working one.  However, occasionally models are discontinued or sometimes we choose to not reorder a model because of early malfunction.  Adding a new model of equipment can bring big headaches.

Sorry, this is a long explanation to get to the point that every time we buy a new model of pump or filter, we have to figure out again how to configure the hose connections.  Sometimes it's not a big deal; but our most recent purchase of a new ultraviolet filter still has us flummoxed.  We have to be able to connect a 2.5-inch hose to a 1.75-inch hose.  We spent an hour at Lowes with two plumbing department employees trying to find something that would work.  Nope.  Tried a local pool and landscaping business.  Nope.  Saw this adapter on Amazon and got our hopes up.  Almost worked...but not quite.

The design concept is wonderful in theory; but the problem is that each individual gradation of size is slightly tapered (slanted) itself...rather than remaining an exact measurement for that entire gradation.  Because of this, neither of the hoses can get a good enough seal.  And, since each section tapers, trying to give the hose ends a more snug fit by pulling it tight with a hose clamp doesn't work either...all because of the slanted tapering.
We've had a koi pond for years and as our koi continue to grow ever-larger (over two feet long now), we've had to install additional mechanical and biological equipment to keep the pond clean and the fish healthy. With two pumps, two biological filters, one mechanical filter, and one ultraviolet filter, it seems like something malfunctions and has to be replaced every year or so. Sometimes it's possible to order the same model and then all we have to do is detach the broken piece of equipment and install the new working one. However, occasionally models are discontinued or sometimes we choose to not reorder a model because of early malfunction. Adding a new model of equipment can bring big headaches. Sorry, this is a long explanation to get to the point that every time we buy a new model of pump or filter, we have to figure out again how to configure the hose connections. Sometimes it's not a big deal; but our most recent purchase of a new ultraviolet filter still has us flummoxed. We have to be able to connect a 2. 5-inch hose to a 1. 75-inch hose. We spent an hour at Lowes with two plumbing department employees trying to find something that would work. Nope. Tried a local pool and landscaping business. Nope. Saw this adapter on Amazon and got our hopes up. Almost worked... but not quite. The design concept is wonderful in theory; but the problem is that each individual gradation of size is slightly tapered (slanted) itself... rather than remaining an exact measurement for that entire gradation. Because of this, neither of the hoses can get a good enough seal. And, since each section tapers, trying to give the hose ends a more snug fit by pulling it tight with a hose clamp doesn't work either... all because of the slanted tapering.