Hi there!
Yes, you are right. Helix Ultimate and the Helix3 are two different frameworks and should not be used together in a single site. As they are different in so many aspects such as module position, layout and many more, hence can cause colflicts as well.
The Arino template is made with Helix Ultimate framework and the Floox template is based on Helix3 framework. If you want Arino then keep Helix Ultimate system plugin.
Kindly, keep templates from only one framework and remove all the instances of the other framework/template.
Best Regards