[Off-topic] 85gallon:
5-letter words

aroma, brome, bromo, carom, promo, proms, roman, romeo, romps, tromp

6-letter words

aromas, bromal, bromes, bromic, bromid, bromin, bromos, caroms, carrom, chroma, chrome, chromo, dromon, pogrom, promos, prompt, romano, romans, romeos, romped, romper, stroma, trompe, tromps, vagrom

7-letter words

acromia, bromals, bromate, bromide, bromids, bromine, bromins, bromism, bromize, caromed, carroms, chromas, chromed, chromes, chromic, chromos, chromyl, dromond, dromons, fibroma, fromage, grommet, neuroma, pogroms, promine, promise, promote, prompts, romaine, romance, romanos, romaunt, rompers, romping, rompish, stromal, thrombi, trommel, tromped, trompes

8-letter words

achromat, achromic, acromial, acromion, airdrome, angstrom, aromatic, atheroma, bichrome, bromated, bromates, bromelin, bromides, bromidic, bromines, bromisms, bromized, bromizes, caroming, carromed, chromate, chromide, chroming, chromite, chromium, chromize, chromous, chromyls, cromlech, dromonds, fibromas, fromages, fromenty, grommets, gromwell, hydromel, intromit, malaroma, micromho, neuromas, orometer, pastromi, pogromed, prodrome, promines, promised, promisee, promiser, promises, promisor, promoted, promoter, promotes, prompted, prompter, promptly, promulge, romaines, romanced, romancer, romances, romanize, romantic, romaunts, scleroma, seadrome, stromata, syndrome, thrombin, thrombus, trombone, trommels, tromping

9-letter words

achromats, aerodrome, aerometer, airdromes, andromeda, angstroms, aromatics, aromatize, atheromas, barometer, barometry, bromating, bromelain, bromeliad, bromelins, brominate, bromizing, carroming, chromates, chromatic, chromatid, chromatin, chromides, chromings, chromites, chromiums, chromized, chromizes, chromogen, cromlechs, dichromat, dromedary, durometer, fibromata, gromwells, hydromels, impromptu, intromits, loxodrome, macromere, maelstrom, malaromas, merbromin, micromere, micromhos, micromini, micromole, neuromata, orometers, pastromis, peperomia, pheromone, pogroming, pogromist, prodromal, prodromes, promenade, prominent, promisees, promisers, promising, promisors, promoters, promoting, promotion, promotive, prompters, promptest, prompting, promulged, promulges, puromycin, pyromancy, pyromania, pyrometer, pyrometry, romancers, romancing, romanised, romanises, romanized, romanizes, romantics, romeldale, seadromes, syndromes, therefrom, thrombins, trombones, urochrome, velodrome, wherefrom

10-letter words

achromatic, acromegaly, aerodromes, aerometers, anadromous, andromedas, antidromic, aromatized, aromatizes, astrometry, atheromata, barometers, barometric, bichromate, bromegrass, bromelains, bromeliads, brominated, brominates, centromere, chiromancy, chromaffin, chromatics, chromatids, chromatins, chromizing, chromogens, chromomere, chromonema, chromophil, chromosome, compromise, copromoter, coromandel, cytochrome, diadromous, dichromate, dichromats, durometers, fromenties, hippodrome, hydromancy, hydrometer, hygrometer, impromptus, loxodromes, macromeres, maelstroms, merbromins, meromyosin, micromeres, micrometer, microminis, micromolar, micromoles, monochrome, necromancy, outpromise, palindrome, peperomias, pheromonal, pheromones, pogromists, polychrome, polychromy, prodromata, promenaded, promenader, promenades, promethium, prominence, promissory, promontory, promotable, promotions, promptbook, promptness, promulgate, promulging, puromycins, pyromaniac, pyromanias, pyrometers, pyrometric, romanising, romanizing, romeldales, scleromata, spirometer, spirometry, thromboses, thrombosis, thrombotic, trichromat, trombonist, unprompted, unromantic, urochromes, velodromes

11-letter words

achromatism, achromatize, acromegalic, aeromedical, aromaticity, aromatizing, astrometric, barometries, bichromated, bichromates, brominating, bromination, bromouracil, catadromous, centromeres, centromeric, chiromancer, chromatinic, chrominance, chromogenic, chromomeres, chromomeric, chromophobe, chromophore, chromoplast, chromosomal, chromosomes, compromised, compromiser, compromises, copromoters, coromandels, cytochromes, dichromates, dichromatic, dromedaries, euchromatic, euchromatin, ferromagnet, fibromatous, fluorometer, fluorometry, hippodromes, hydromedusa, hydrometeor, hydrometers, hydrometric, hygrometers, hygrometric, intromitted, intromitter, lepromatous, meromorphic, meromyosins, micromanage, micrometers, micromethod, monochromat, monochromes, monochromic, necromancer, necromantic, nonaromatic, oneiromancy, outpromised, outpromises, overpromise, overpromote, palindromes, palindromic, phytochrome, polychromed, polychromes, preromantic, promenaders, promenading, promethiums, prominences, prominently, promiscuity, promiscuous, promisingly, promotional, promptbooks, promptitude, promulgated, promulgates, promulgator, prothrombin, pyromancies, pyromaniacs, pyrometries, romanticise, romanticism, romanticist, romanticize, sclerometer, spherometer, spirometers, spirometric, synchromesh, theobromine, thrombocyte, thromboxane, trichromats, trombonists, unpromising

12-letter words

achromatisms, achromatized, achromatizes, acromegalics, acromegalies, adrenochrome, aeromagnetic, aeromedicine, amperometric, antiromantic, antithrombin, apochromatic, aromatherapy, aromatically, astrometries, atheromatous, bromegrasses, brominations, bromouracils, chiromancers, chiromancies, chromaticism, chromaticity, chromatogram, chrominances, chromocenter, chromonemata, chromophores, chromophoric, chromoplasts, chromosphere, compromisers, compromising, dichromatism, electrometer, erythromycin, euchromatins, ferromagnets, fluorochrome, fluorometers, fluorometric, gyromagnetic, hydromancies, hydromedusae, hydrometeors, hydromorphic, intromission, intromittent, intromitters, intromitting, micromanaged, micromanager, micromanages, micromethods, monochromats, monochromist, necromancers, necromancies, neurofibroma, nitromethane, outpromising, overpromised, overpromises, overpromoted, overpromotes, palindromist, panchromatic, penetrometer, photochromic, phytochromes, polychromies, polychroming, postromantic, promontories, promptitudes, promptnesses, promulgating, promulgation, promulgators, prothrombins, psychrometer, psychrometry, pyromaniacal, pyromorphite, respirometer, respirometry, romanization, romantically, romanticised, romanticises, romanticisms, romanticists, romanticized, romanticizes, sclerometers, spectrometer, spectrometry, spherometers, spirometries, stromatolite, tellurometer, tenderometer, theobromines, thrombocytes, thrombocytic, thrombolytic, thromboxanes, trichromatic, ventromedial

13-letter words

accelerometer, achromatizing, adrenochromes, aeromechanics, aeromedicines, antiromantics, antithrombins, aromaticities, aromatization, bildungsroman, bromocriptine, chromatically, chromaticisms, chromatograms, chromatograph, chromatolyses, chromatolysis, chromatolytic, chromatophore, chromocenters, chromonematic, chromoprotein, chromosomally, chromospheres, chromospheric, dichromatisms, electromagnet, electrometers, erythromycins, ferromagnetic, fluorochromes, fluorometries, gynandromorph, heteromorphic, hydromagnetic, hyperromantic, intromissions, isochromosome, macromolecule, metachromatic, micromanagers, micromanaging, monochromatic, monochromator, monochromists, neurofibromas, neuromuscular, nitromethanes, oneiromancies, overpromising, overpromoting, palindromists, penetrometers, photochromism, polychromatic, promiscuities, promiscuously, promotability, promotiveness, promulgations, psychrometers, psychrometric, pyromorphites, respirometers, respirometric, romanizations, romanticising, romanticizing, saccharometer, saccharomyces, spectrometers, spectrometric, stromatolites, stromatolitic, superromantic, synchromeshes, tellurometers, tenderometers, thrombokinase, trichromatism, ultraromantic, unpromisingly

14-letter words

accelerometers, achromatically, antidromically, aromatherapies, aromatherapist, aromatizations, barometrically, bildungsromans, bromocriptines, chlorpromazine, chromaticities, chromatographs, chromatography, chromatophores, chromodynamics, chromoproteins, electromagnets, electromyogram, ferromagnesian, ferromagnetism, ferromanganese, gynandromorphs, gynandromorphy, heteromorphism, hydromechanics, interferometer, interferometry, isochromosomes, macromolecular, macromolecules, micrometeorite, micrometeoroid, microminiature, monochromatism, monochromators, neurofibromata, nonchromosomal, orthochromatic, photochromisms, psychrometries, pyrometallurgy, pyrometrically, respirometries, saccharometers, spectrometries, thromboembolic, thrombokinases, thromboplastic, thromboplastin, trichromatisms, uncompromising, unromantically, unromanticized

15-letter words

antiferromagnet, antiromanticism, aromatherapists, chlorpromazines, chromatographed, chromatographer, chromatographic, electromagnetic, electromyograms, electromyograph, ferromagnetisms, ferromanganeses, gynandromorphic, hemochromatoses, hemochromatosis, heterochromatic, heterochromatin, heteromorphisms, hydromechanical, hydrometallurgy, interferometers, interferometric, micromanagement, micrometeorites, micrometeoritic, micrometeoroids, micromorphology, monochromatisms, necromantically, promiscuousness, promotabilities, promotivenesses, rechromatograph, romanticization, saccharomyceses, thromboembolism, thromboplastins, uncompromisable

16-letter words

antiferromagnets, antiromanticisms, chromatographers, chromatographies, chromatographing, chromolithograph, electromagnetism, electromyographs, electromyography, enterochromaffin, extrachromosomal, gynandromorphies, gynandromorphism, heterochromatins, hydrometeorology, interchromosomal, interferometries, micromanagements, micromanipulator, micrometeorology, monochromaticity, pheochromocytoma, pyrometallurgies, rechromatographs, rechromatography, romanticizations, superromanticism, thrombocytopenia, thrombocytopenic, thromboembolisms, thrombophlebitis, uncompromisingly

17-letter words

antiferromagnetic, chromolithographs, chromolithography, electromagnetisms, electromechanical, electrometallurgy, electromyographic, gynandromorphisms, hemochromatosises, hydrometallurgies, hydrometallurgist, immunocompromised, micromanipulation, micromanipulators, microminiaturized, micromorphologies, monochromatically, neurofibromatoses, neurofibromatosis, pheochromocytomas, promiscuousnesses, pyrometallurgical, radiochromatogram, rechromatographed, superromanticisms, temporomandibular, thrombocytopenias

18-letter words

antiferromagnetism, chromolithographed, chromolithographer, chromolithographic, electromyographies, hydrometallurgical, hydrometallurgists, hydrometeorologies, hydrometeorologist, micromanipulations, micrometeorologies, micrometeorologist, micromorphological, monochromaticities, pheochromocytomata, polychromatophilia, polychromatophilic, radiochromatograms, rechromatographies, rechromatographing, spectrofluorometer, spectrofluorometry, thrombophlebitides, uncompromisingness

19-letter words

antiferromagnetisms, chlorofluoromethane, chromatographically, chromolithographers, chromolithographies, chromolithographing, electromagnetically, electromechanically, electrometallurgies, hydrometeorological, hydrometeorologists, interferometrically, micrometeorological, micrometeorologists, neurofibromatosises, polychromatophilias, spectrofluorometers, spectrofluorometric

20-letter words

chlorofluoromethanes, microminiaturization, spectrofluorometries, uncompromisingnesses

21-letter words

antiferromagnetically, electromyographically, microminiaturizations

23-letter words

dichlorodifluoromethane

24-letter words

dichlorodifluoromethanes