Sorry for the concern, there is no problem with the unit. I will explain. When the plexi top gets pressed against the smooth nickel block there is a very very tiny gap that that remains. There are 2 kinds of visual effects from this pressed gap. The first appears as a halo, rainbow, or hologram effect, this is more common when clear based coolants are used. The second visual effect appears as a whispy, dusty, or scratched effect, this is more common when solid based coolants are used. When a solid coolant is used, some of the particles that make up the colour get stuck in this very tiny gap and remain there as a residue. Be assured there is almost no flow outside the channels in that gap, and this is a visual aesthetic issue only, there is no performance loss whatsoever. You can try and clean the block by flushing with distilled water or manually taking the block apart and using warm soapy distilled water (baby bottle soap works well) and a soft bristle brush to clean the areas where the solid coolant became trapped, but it will reoccur with prolonged use of solid coolants again if it happened before. I apologize for the upset, there is no performance issue with the product and all 2 piece waterblocks may have this effect.
