When Is 'cycle' Done?

[Tessla]

...newly idealistic and overly sanctimonious fish tank person

There is no such thing!

Never heard of only testing nitrite if the pH goes up, have heard plenty of bad info from fish store though. There are tons of things that can cause pH to increase, I'd get a good liquid test kit for nitrites and nitrates.

As for pH, you want that to be stable and not fluctuating. I've got a pH of 8 from the tap since I'm in an area with extremely hard water, if you've got hard water as well you won't have to worry about pH fluctuations... but no soft water loving fish like discus. If it stays at 7.5, that's perfect, don't bother with the chemical fixes.

I have the Hagen Elite Stingray (Underwater Series) for upto 10 US gallons.

Looked it up and it seems to take a small foam piece? If you can get a piece of mature filter sponge/floss cut to that shape it should work fine in your filter.

 

[Miss Wiggle]

yeah get a test kit for nitrite, that sounds like spectacularly bad advice