All the issues I have seen here and other places are with the 2000 19/25 version. I have not seen any issues with the 1500?
So Paul, I don't think you will have a problem. Just make sure you strip it before use and silicone grease all O rings and seals as well as a little on the impeller shaft.
Unless anyone out there knows different?
I assume that when Aquael decided to change the 2000 to 19/25 pipes, they did not take the design back to scratch. They just fiddled with the original design to make it take larger pipe. Fundamental design mistake to save money. I bet they did not even do any new pressure calculations on the rest of the filter. I feel that is why it is leaking. The increase in pipe size will change the pressure up and down in all parts of the filter. Even a drop in pressure can cause an o ring to leak as it is not held in position with the same force as before.