for filter food, macro, iron, (additives) Kent… Is there a experation date?
I’ve only seen a experation date on the live food like DT’s and I believe on some of the test kits.
minerals suppliments like iron for macro should keep a long time. but algae mixes for coral food will probably go bad, loose vitamins and stuff over time. might spoil even in an unopened bottle. and once opened do have a shelf life. bacteria gets in the bottle when open to the air, and starts feasting on dead algae mixes and protein amino acid suppliments. and just oxygen getting in the bottle will start oxydation of much of it. so use it up once open, not store it for a rainy day.