Clamps(metal and plastics)
garden hose (running for safety over flood)
transfer and self priming pump
waterproof flashlight (bright white, red and UV)
towels towels (for my hands and for equipment)
Credit/debit card (for scraping or leveling)
Step ladder (to reach some points in the DT )
Folding stool for the same as prev. and sitting on front )
knee protectors (when I have to stay for longer front of my sump to deal with)
Mason jars (to keep for a while some organisms etc ...)
Tupperware and many other boxes ( for dipping, investigating/inspecting corals and invertebrates )
Scrub brushes and tooth brushes (for cleaning etc)
Zip stripes (for tightening hoses and wires, lights etc )
Brute trash cans (for salt mixing and LR seeding curing etc)
Turkey baster (for whatever you can need)
Vinegar (for cleaning, really a lot of vinegar)
computer/laptop (for web reading/writing, calculations, log keeping etc)
UPS (for some energy after the mains go down)
RO/DI filter
canisters for RO (that I use for some custom build reactors)
auto TOP OFF
toilet flush kit for filling barrels (with RO/DI water and salt mix)
Plastic barrels and jugs for keeping water etc
Plastic storage container (for the water from the sump if it over flood)
many different clips like jubilee and others (for hoses and so on)
Arduino and RasPi controllers (for some functions )
Terry clips for hoses and PVCu pipes
Underfloor heating mat (for the under-gravel filter, which don't use at the moment)
1ml-50ml Syringes (have many of them and most of needles
beer brewing thermostats (for keeping the temps on level- controlling the heaters and the water chiller)
AC (air cond. self priming pump for the skimmate from the prot. skimmer, because the skimmer cup is under the sump glass level)
Bathroom plastic vacuum holders/sup/plate/for soap (with many extra holes I use them when I'm placing frags in the DT to acclimate the corals to the light )
plastic baskets (for keeping frags and corals on top on the DT in the water)
magnifying glasses (which I use for soldering SMD, that one when I dip the corals, to watch them, observ. and clean)
many measuring cans (for water, chemicals and mixes etc...)
Portland cement (for building rock structures )
plumbing o-rings for sealing pipe joints etc)
PTFE - teflon tape for BSP fittings
bleach for washing the filter socks and so on
toilet paper and napkins (for quick drying)
Super glue(cianoacrilate) ,Epoxy resins etc (for gluing stuff and corals)
Computer power supplies for 12v and 5v high amps for powering most of the equipment
and so on, can't write all of the non fish tank tools and equipment I'm using, but I think I cover most of them!
Sorry for the long reading, but some of you can find some stuff here good for you to use for some purposes x