Just out of curiosity what are you planning on putting it on?
Do yourself a favor and either build a sump, if you don't have one, and get an in sump skimmer. Even though you are fish only now that will probably change in the future, and with a sump and a better skimmer your fish will be healthier regardless. Just by your photo I suspect that I have the same HOB filters that you have (based on the intake tube and the strainer) I had two of those on a fresh water 75 and they were not sufficient for that so they definitely won't be able to handle a salt water tank. They are both in my garage now and I went with 2 tidal 100s for my fresh water set-up.
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question is, do you currently need a skimmer?
You have a fish only tank.
How are your nitrates and phosphates?
How often are you changing water?
If they are good and your not and your happy with how often you are changing water for waste export and water maintenance, than you probably don't need a skimmer.
I might go with cycling some live rock to add to the tank to increase biofiltration before adding a skimmer unless your adding SPS or LPS to the tank and you need low nitrates and phosphates. Upgrade your HOB filter to something that will give you more flow for saltwater. IF you need to add a skimmer, there are HOBs that are better than having that all in one filter.
All saltwater aquariums will benefit greatly from use of a skimmer. It removes a lot of filthy dissolved organics from the water.
https://www.marinedepot.com/aquamaxx-cones-hob-hang-on-back-protein-skimmer Also look into this skimmer.