Maintainance app, or pen and paper?

[gregzz4]

Guess it's pen and paper for me

I wrote an Excel log/spreadsheet and use it all the time
I print off blank sheets and they pile up until I transfer them to a storage binder ......
I record every test, additions/deaths, lighting changes, dosing changes, water changes, changed a brand of product

I find it very useful when looking back to source issues
It's also helpful just for the fact that I can date when I did 'what' with bulbs, dosing changes, whatever
What buckets of salt I used, batch #s ....

The uses are endless