Most outlets like that are connected with little metal tabs. You would not have to make little jumpers. Unless you broke them metal tab jumpers built in. That said you would be much better off to replace the outlet in the wall with the GFCI one, then just run your power strips from the walls. Using an extension cord with an outlet like that violates fire code.
Really? We have them in a few spots in our facility at work and it has never been an audit finding (internal, ISO, FAA/DOT, etc)
Yes really. Does not matter what you have going on at work, and internal, ISO, FAA/DOT do not have anything to do wtih it. It is OSHA, in some situations; the NFPA, local and state building and electrical authorities having jurisdiction in most any location/situation. Any issue arising from the illegal use of extension cords, as well as multi-outlet devices (power strips) will result in fines that would boggle your mind, not to mention litigation resulting from any injury, death, or loss resulting from the use of same. One would think that a "company" would be more responsible than that, but...
The applicable concepts here are the extension cords in continuous use, (more than 3 hours) and multi-outlet devices used inconsistent with their labeling. (being labeled in most all cases: Not for continuous use.)
I have yet to see an aquarium installation that does not violate NFPA, NEC, and/or state and local building codes in some way. Hobbyists have a nack for thumbing their nose at things that make what they are doing inadvisable, becasue "everyone" does it.
That is all well and good, and of course the "compliance cops" won't be around to inspect/approve the death trap that has been put together. (not everything is a "death trap", just sayin.
They won't be around that is, till something burns down or someone gets hurt. Then the NFPA, Fire Marshall, and homicide detectives will take a great interest in what was going on.
The logic is pretty simple. The most common "residential" accident is caused by extension cords (broken ankles, legs, arms, necks) (source NFPA) and the most common cause of loss/injury/death associated with aquariums is due to fire caused by the mis-use of multi-outlet devices. (Source: Arson.org,) rather than electrical shock that most obsess over, (indicated by the directed use of GFCI recepticals—regardless of what laws/regulations/codes are violated to include them.)
The NEC forbids the use of extension cords (in any occupancy commercial/residential/special) for more than three hours (continuous use,) and by inference—use of a (mulit-outlet device) listed item inconsitant with its labeling (ul listing) although there are specific prohibitions concerning multi-outlet devices attached to the structure, or a workbench, desk etc. which would include your aquarium stand in an investigation.
The point is not "don't do it, because it is illegal." That would accomplish little. Rather the point is: Just because the facility where you work does it, your next door neighbor does it, reefers x, y, and z, do it—does not make it legal, safe, or advisable.
I would advise that you hire a competent electrician to evaluate the situation, and install a suitable number of code compliant outlets to serve your needs as outlined in the NEC. Sure, no one is going to care what you do, except (depending on the nature of the incident) the Fire Marshall, homicide detectives (if it is that serious,) arson investigators, and your insurance company who will refuse to pay due to the violations. (The whole point of these types of investigations is to get the insurance company off the hook.) What are the odds? Well, sufficient for the NFPA to be concerned anyway.