Remora HOB skimmer filling with water
 

I just set up a Remora skimmer (bought used with a maxijet 1200) and the collection cup has been filling with water about every 45minutes.
As I understand it there is a "break-in period" but at the rate the cup is filling I can't leave the thing unattended for fear of a flood. I've got the cup pushed up all the way. I pulled the manual online and it mentions that water conditioner could cause such foam. I'm stuck using tap water (too poor for RO/DI). I've been using aquaplus. Are there any conditioners that don't cause this?
On a related note, could Aquaplus potentially cause problems in a reef tank since the active compound is EDTA which also chelates Mg2+?

Is the collection cup set at its highest position, it should have a big o-ring to adjust it with.

It is set as high as the cup will go.

Well, I'm not familiar with the aquaplus product, have you tried "Prime", or just skip the conditioner for now...

I have yet to try prime. I haven't added any new conditioner in a week. However since I have to keep emptying the cup (~10 times now) it is slowly draining my tank and I'll need to top up eventually (top up water would need to be conditioned).

Maybe try leaving the cup out for awhile till it's broke in.