OK, just to slightly change my original answer - I skimped a little on the research!
I simply googled your filter and looked at the first result that showed the filter capacity (
here, if you're interested!).
This said it was suitable for tanks up to 57L, hence my answer. Maybe they got their numbers the wrong way round?
Anyway, it also claims a 300lph capacity. A filter should be able to filter your tank 4 times per hour, at least. As your tank is 70L, this would mean 280lph.
So, I guess your stingray should be OK, but personally I'd add a second one - the filtration is right at the limit, and could cause you headaches in the future. A second one would mean plenty of filtration, and a backup if anything goes wrong.
So, if it were me, I'd get started with the existing filter, but get a second one to go with it in the near future.
:EDIT: If you're set on getting a completely new filter, I'd recommend the Fluval 2 plus. It's a good filter (mine is seven years old, no major issues with it yet!) with plenty of media options, and not too badly priced. It's also rated for 400lph, which will be fine for your tank.