Forge version: 1.11.2-13.20.1.2476
Botania version: r1.9-345

This is more a suggestion than a bug, but anyway I hope this could be improved.

When equipping the Tainted Blood Pendant of Night Vision with a full Mana Mirror in the Inventory, I get the Night Vision effect (which is a very nice feature) but only for 14 seconds, an it gets renewed only after the countdown is down to 12, 10 or often even only if its down to less, like 6 or 4 seconds left. Maybe this randomness has to do with serverlag or maybe lag on the clientside, eventhough it also happens when the Server seems to run pretty smooth.
The Problem is, when the counter is under around 10 seconds, the flickering starts that shows that the effect is wearing out soon. My suggestion would be to make the countdown start at a higher level, like 30-40 seconds, so even if the renewal is late due to lag (or whatever reason), the flickering doesnt start every time.