Red Sea 100 Micron Felt Fine Polish Filter Sock

Achieve ultra-polished water clarity with the Red Sea 100 Micron Felt Fine Polish Filter Sock. Designed for mature aquariums with low particulate matter, this fine-mesh sock captures the smallest suspended particles that coarser socks miss. Ideal for Red Sea Reefer and MAX-S sumps, it also fits any standard 4"/10cm filter bag holder.

Looking for more filtration products? Browse our Filter Media & Cartridges.

• 100 micron fine felt media for polishing water in mature, low-waste aquariums
• Designed for Red Sea Reefer and MAX-S series sumps
• 10.5"/26cm length fits standard 4"/10cm filter bag holders
• Washable and reusable — rinse in warm water and reuse multiple times
• Suitable for both freshwater and saltwater aquariums

When should I use a 100 micron sock instead of a 225 micron?
Use the 100 micron sock on mature, established aquariums where particulate levels are already low and you want crystal-clear, polished water. For newer tanks or heavier bioloads, start with a 225 micron sock to avoid frequent clogging.

How often should I clean this filter sock?
Check it every 2–3 days. Because the finer mesh catches smaller particles, it will clog faster than a 225 micron sock. Rinse in warm water to restore flow.

Will this fit non-Red Sea sumps?
Yes, it fits any sump with a standard 4"/10cm filter sock holder. Verify your holder dimensions before purchasing.