I have a large water pump for my pond (about 15 years old) the motor still runs, but it doesn't have the power it used to. If I had a waterfall it would not make it up
Anymore. Do these pumps on average just get old and don't have the power any more? Or should I take it apart and attempt to fix it. I replaced it with a 500 gallon one and it just doesn't have the power to fill my additional filter the way the other did. I hate throwing things away that could be fixed, but I really don't have the space to store it and it depresses me when I look at it.
So my question is toss it or take it apart and try to fix a potential problem.

A friend of mine works for one of the largest pond supplier in the country. He tells me that any pump more than 5 years old should be discarded and replaced with a new high volume pump that uses less power. They send one of their men, my friend, to China to spec out the most efficient pumps they can find since most pumps run 24/7/365 for many years. Aquascapes imports their pumps from China and Ihave been very please with the power usage. Welcome to Aquascapes.com Online Store | Aquascaping Supplies

So your saying I should discard the old pump no matter what? Yes it has run 24/7/365.

I would, its like a 15 year old refrigerator. It uses too much power an has lost its effienecy. Aquascapes pumps are a bit pricey but you can shop around. Read the stats on each box and look for a pump that uses less power but can match the original gph of the original pump. I have never had a pump last 15 years.