Pulsing Xenia vs. Scissors

Just curious, what part of water quality is "bad" when not pulsing? Higher nitrates, lower calc, mag and/or alk? Just curious as like I said I had it in two tanks with "identical" parameters (pH may be the only difference as it is slightly higher in one tank) and it pulsed in one and not the other, regardless of water changes.

 

Good to know. If it doesn't pulse well, I'll try it in a different part of the tank. I've also read that it is a good one for beginners and tanks with some nitrate readings...don't know if this is true or not though.