Katrina,
I always like to start this explanation by relating it to the rear end in a car. In a car, the rear end (or drive end in case of front wheel drive) has what is called a differential. The purpose of the differential is quite simple, and can be applied in any pump application.
When we take a corner in a car, the wheels are required to spin at different speeds. If you take a 90 degree right turn into your driveway, the right side wheels have far less distance to travel than the left hand side. In this situation the left hand, or the "outside" wheel is turning several more revolutions than the inside wheel to make the same turn. Both sides of the car end up pointing the same direction when the turn is over but the outside wheels travelled further. Pretty simple concept. Lets proceed
On the suction side of any centrifugal process pump, the same rules apply as far as making the turn. In your case, the saltwater on the outside must travel further than the saltwater on the inside of the 90 degree turn. Also, just as the outside wheel on the car starts to go faster (more revolutions), the saltwater on the outside of the 90 degree fitting is travelling farther to reach the same destination. The problem now is that the velocity of the saltwater on the outside of the fitting has increased as it is trying to catch up. As the velocity of any fluid under pressure increases, the pressure drops. Now there is a velocity differential, thus a pressure differential right in front of the impeller. Not good.
Books with over 500 pages have been written on this topic and I am not going to bore you with a bunch of scientific crap. Get rid of the 90 degree fitting. If you must use it to make your set up work, then allow 10X the diameter of the pipe BEFORE the fluid hits the impeller. There must be a straight shot of pipe going into the pump. This will give the fluid a chance to equalize pressure and the impeller will treat it all the same. If you have 1" pipe, allow 10 inches of straight PVC before the pump and so on.
Also, never throttle back the discharge of a pump. NEVER. This creates a hydraulic force within the pump that tries to bend the shaft. Its not my opinion, its just the laws of physics. If the pump is oversized and creates too much flow, just install a discharge bypass. This can be done with a simple T fitting and a ball valve. Install the T fitting on the discharge of the return pump just at the top of the sump, immediately followed by the ball valve. Run a line off the T fitting back to the sump. If your pump is oversized and creates too much flow, throttle back your bypass valve and divert the water back to the sump. This will give you the perfect amount of flow to your display and let your pump operate close to its best efficiency point (BEP). When a pump is running off of its BEP it runs hot, wastes energy and always ends in premature failure.
Get your plumbing straightened out first, then determine if the pump has been damaged. You might find that the pump operates to your liking when properly piped. It could have sustained some damage depending on how long it has been running in its current environment. The GEN-X is a good pump.
If you have any questions about setting up your pump, please do not hesitate to ask. I want to help!
