First off, I believe you should do some research regarding your target users' screen sizes to see if it actually falls above or below their screen's fold, in case you have not created a fixed footer. The best case solution would be to place it in a fixed footer at the bottom of the viewport.
Now going by your premise that the link falls above the fold, since the users are stating that they are not able to frequently find the business login link, I believe you are either not using any kind of highlighting towards the link, or probably using a ghost button to get them there. Lemme put this out loud to you- DON'T USE GHOST BUTTONS. Ghost buttons have ghost conversions. I'd rather suggest you place the link in a colored button based on your brand guidelines.
You could otherwise land them onto a page that has two primary action button (okay, primary client login more prominent than the secondary business login), and let the users move to whichever direction they want to from there.
If you otherwise just wish to leave it as a link, I'd suggest one of the following different ways via which you could accomplish this:
- You could use the google.com approach of presenting the link to Business login at the bottom of the screen.
- You could use the udemy.com approach of presenting the links at the header navigation with all login options equally prominent.
I hope this answer helps. Lemme know in case you have some more insight to share regarding the scenario for further suggestions.