Help! High Nitrite Levels!

[GouramiGirl87]

Uh oh! My Nitrite Levels are High!! like 6 or 7
I've heard they're supposed to peak, before they go back down, but they've been riding at 4-5 for a week.
Should I do a 50% water change? or a 25%?

 

[teaker1s]

several small rather than one large water change is generally thought to be better