ugh...i hate to admit it...but i keep a very detailed excel workbook with multiple worksheets

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water params tab: tracks weekly water test results, water changes, media, equipment, filter changes, feeding/salt changes, along with any possible correlations.
active stock tab: date, from who, lineage, trade/purchase price, condition, color, initial size, placement in my tank. it ain't perfect, but enuf for me.
expired stock tab: all the ones that didn't make it or i decided to give up on.
fish load tab: date, where i purchased, price and condition.
coral distribution tab: who and what i've sold/traded/given too. this is a great resource for reacquiring something back or calling in favors in return

. but sadly, it also tells the test of time. since many people exit the hobby, earn a bad reputation or magically "forget" what i gave them and i'm left high and dry

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i probably spend as much time keeping it updated as i do maintaining my tank :mad2:!