loss of efficiency over time?

Do all return pumps just lose their gph over time? I bought a MAG18 9mths ago and it would turn my tank into a whirlpool. Then I added a aqua 57 watt UV inline with a manifold that ran a brs pellet reactor. After giving up on the pellets about 3 mths ago I removed the reactor and the manifold hoping to regain my pressure. Nothing noticeable. Aqua has to warranty my UV so I took that out of line so now its just a straight shot to my 2 heads (one of which is the belled turbo head thing). Its still not what it used to be. Ive cleaned the pump multiple times as recent as 2 weeks ago and Im not seeing what it could be that would slow down my flow to a point that it looks like my pumps are off in the tank.

Is this typical or are magdrive pumps just ****?

 

Both. Yes pumps do lose some efficiency over time(depending on the magnets and type of pump).
Mag drives last a long time but are energy hogs.They also produce alot of heat compared to similar available pumps.
Most pressure loss comes from algae or detritus forming in the pipe as well as precipitation associated with dosing.I am sure Powerman will make an appearance.

 

If you start with a clean pump everything is good. Calcium and biological matter build up and cause drag and friction... but 60hz is 60hz, and as long as it is turning at that speed, it will put out the same gph...it just will use more power to do it. If the magnet is not strong enough to hold the field, then it will be much worse than just a few GPH off. If it has actual impeller damage that will do it too.

So you have to soak it is vinegar to make sure it is clean. The heat of the rotor will cause scale deposits. Line loss is a much bigger player. What ever build up you have in your lines will cause flow loss like Vinny said.

Mags are not "bad" pumps and do not add a "lot" of heat compared to others. All it comes down to is watts. How many watts for a given GPH. Ehiem will use less than a Mag and therefore be more efficient, and add less heat. I saved 15 watts when I switched my pump... but is 15 watts of heat worth it to you not to use a Mag... only you know. They certainly are solid performers and readily available. But I did switch mine because I was trying to save power and heat and that and other changes allowed me to ditch my chiller.

 

Mags generally last forever, and are good pumps for the money (we've got some that we have no idea how old they are...like well over over a decade). The larger ones (9.5 and larger) do indeed warm up the water a bit, as they aren't as efficient as others.

I'd run the pump in a bucket of vinegar and water (25% vinegar or better) for awhile if you've already had it apart and it's clean.

I have to agree...look to your lines...even your drain lines.