I take it, this is not your own pool?

Regardless, it will take a lot more pictures than the one you sent, for me to work out your piping layout in my head . . . and that's a necessary first step toward helping you.

If you are a plumber, by chance, then this may help:

1. Install a check valve at the base or lowest point of the waterfall suction line.
2. Install a prime valve, consisting of a sill cock tapped into a 3" PVC pipe/socket hub connection, and a female/female 3/4" hose to hose connector.
3. Prime by filling till water exits the pump basket -- pump basket lid MUST be open BEFORE you begin filling. Shut off sill cock, close pump, and attempt prime.
4. Several attempts may be needed, because of air trapped upstream of the check valve.

If you can't send more pictures because of your employer's privacy concerns, you need to enlist your employer's plumber, and have him do the list above. Anybody who can afford to run a fountain 24/7 like that can afford to fix it right.

(And, if your employer can NOT afford those changes, look for another job! I've done work for some of those folks who had $500,000/year incomes . . . and $800,000/year lifestyles. My experience has been that they'll short the 'help' every time, before they'll give up the new Mercedes lease or the St. Bart's vacation they planned!)