Quartz Sleeves in UV sterilizers over time will get dirty and loose their ability to transfer light effectively. By replacing the quartz sleeve your UV will run like new again with almost all of the light emitted from the UV lamp passing through the Quartz sleeve.
It's gonna get dirty By Charles on 6/27/2015Charles would recommend this product to a friendFor sure you quartz sleeve is going to get dirty. I suggest a spare so you can just remove the dirty one and take your time soaking and cleaning in. While it's soaking, you have already put the new one in. Also, just in case you break it when you change the bulb, consider having a spare. I am all for spares and redundancy when it comes to reefing.