John, there is a high-end electrostatic air filter that you can use, together with a dedicated air handler that only recirculates air for the electronics/music room itself, that will minimize or solve the problem.
I too am cursed with about 210 salty feet of waterfront, largely due to my wife's irrational desire for same, and am less than 40 feet above mean high tide. I have a separate room on the back half of the lowest of four stories, about 40 feet by 40 feet square, dedicated to musical instruments and other electronics with corrosion potential, such as the CRT-based home theater. All my vintage guitars and basses are in there, as well as brass and woodwind instruments, and some rare strings, and my book collection too.
The contractor totally vapor-sealed all four walls, the floor, and the ceiling, put in a double-entryway with an intermediate foyer, sorta like airlocks, that prevent both doors being opened at the same time.
He then installed a standard Ruud HE 3000 cu ft air-handler with heating and air-conditioning, a commercial humidity control logic cabinet and humidifier, and not just one but three AprilAire 5000 5th-generation electronic air-cleaners, ganged in series.
The system runs at a low speed all the time, is nearly noiseless, and the AprilAires positively take out any trace of suspended salt micro-powder from any air that gets in during normal entry and exit, before it even has a chance to take its first trip around the room's airspace. Most of this comes off shoes and a little off clothing, along with clothing fibers and sloughing skin cells. The inlet of the air-handler is a grate on the floor after you enter the inner room, and this pulls off what your shoes bring in.
The system maintains a dust-free 45% RH plus or minus 3%, and 75 degrees F plus or minus 2 degrees, year-round. The weird thing is, at certain times of the year, both the heat and the air-conditioning will kick in and run at the same time, in order to meet the humidity reduction called for by the system logic controller!
It wasn't terribly expensive for only a 1600 ft sq room, any museum can recommend to you one or more specialty contractors who do this kind of stuff. Cost maybe $15K for the main pieces, and maybe another $10K on the grate and ducting, and the plastic-ey spray seal on all six surfaces and Tyvek laid over that, and then the spray-on high-density urethane foam insulation that they put between the 2x6 wall studs to further seal out humidity intrusion from outside the room's walls. Then there was a moderate labor cost on top of that to put it all together. YMMV depending on local contractor greed, but all the components' actual cost is less than $15K to $25K.
I know it sounds like overkill, but it has kept every bit of surface metal on all these instruments (including Rickenbackers

) and the electronics gear absolutely shining and corrosion-free for nearly five years now, on veerrry windy and salty Atlantic Ocean waterfront. Dust-free too. The outside air is so salty that the exterior doorknobs of the house need replacing every three months. Considering the value saved in preserving these instruments from otherwise certain salt and humidity damage, it was a bargain at that price
Just my 2 cents worth....
Elys