Agree with slothy - Rio pumps are crappy.
Skilter filter/skimmers are crappy. Both the 250 and 400 - the manufacturer should be ashamed of themselves.
Most of the introductory low end products are normally not so good either.
You'll know them when you see them.
Examples are everywhere - where the manufacturer has 4-5 models with cheap to expensive price tags.
Usually ( not always ) the low end units are junk in comparison.
Skimmers are all over the place from $20 bucks to several hundred dollars.
Some fish tank thermometers is another area.
You have a 3 inch scale from 0 to 100 degrees F, with a measly 1/4" green safe area ?
What's up with that crap LOL
Like I need a thermometer for my tank that reads 0 F ????
Cheapo !
You get what you pay for is so true with this hobby.