How To Clean Filter Socks

Filter socks are one of the most basic yet effective forms of mechanical filtration for reef tanks. The water that exits your tank through the overflow pipes goes directly into a filter sock that filters out particulates before the water moves through the remainder of your filtration. A filter sock effectively removes larger particles of waste and leftover food before they get a chance to break down or settle. 

As a filter sock clogs up, it is important to remove them to effectively export waste from the aquarium. It is recommended that you remove clogged-up filter socks and replace them with a clean one every 3-5 days. That means your going to go through filter socks quite quickly so we always recommend having at least 3-4 socks on hand at all times. The good news, filter socks can be cleaned and reused! 

Types Of Filter Socks

Filter socks come in a few different styles. Those with a rigid plastic ring on top are designed to set inside a filter sock-holder which is commonplace on most sumps and even some all-in-one aquariums.  The standard sizes are 4” and 7” diameter socks with the larger socks intended to handle higher flow rates on larger aquariums.

The drawstring style filter socks work nicely if you do not have a filter sock holder, you can simply tie the sock onto the end of a tube or pipe in order to filter the water.

You will see filter socks available in both a fine felt material and a nylon mesh. Fine Felt filter socks will pull more debris out of the water than their mesh counterparts but will also need to be changed more frequently. The nylon mesh socks are a bit easier to clean but still will not catch as much debris.

Filter socks also come in different micron sizes as well which refers to the porosity of the material. The smaller the micron rating, the smaller the pore size in the material.  A 100-micron sock is will collect smaller particles of debris compared to a 200-micron filter sock, but that also means the smaller micron sock will clog up faster. 

How To Clean Filter Socks

Everyone’s sock exchange and maintenance schedule will be slightly different depending on their individual systems and how much waste they are dealing with.  A good rule would be to change or clean them every 3-5 days, or as soon as they get discolored. Keeping on this schedule will help to ensure that your filter socks are removing the organics from your tank rather than just storing them.

The best approach is to keep at least 3-4 filter socks on hand at all times, many of us end up with a dozen or more.  This way you always have a clean filter sock available and you can then wash the dirty socks in batches.  When it comes to cleaning your filter socks, there are a few different routes you can take. 

1. Washing Machine

The most efficient technique to clean your socks is to turn them inside out and throw them in your washing machine.

  1. Run a hot rinse cycle without the socks first, this will rinse away any detergent and soap from the washing machine
  2. Toss in the socks and run a heavy-duty cycle with hot water. Use 2-3 capfuls of fragrance-free bleach. NO SOAP OR DETERGENT!
  3. Once complete, you can remove the socks and let them air dry for 2 days before using them. 
  4. If you smell residual bleach or need to use them before they can dry completely, soak in a bucket of fresh water and water conditioner for a few hours to neutralize any bleach. 

2. The Bucket Soak

Fill a bucket with hot fresh water and add 1-2 capfuls (per gallon of freshwater) of fragrance-free bleach. Then let the socks soak in the bleach solution for a few hours or even overnight. After soaking, remove the socks and rinse the socks inside and out with a hose or under the faucet. It's not a bad idea to soak in a bucket of fresh RO/DI water and water conditioner thereafter to neutralize the bleach. It is always best to let them air dry before using too because this will decompose any trace amounts of bleach. 

3. Power Washer

Perhaps the quickest way to clean out your filter socks is with the use of a power washer or high-pressure water hose. With this method, all you really need to do is blast the socks until they appear to be clean. Be sure to turn them inside out and rinse both the inside and out. Let them dry before use. 

**Pro-Tips - When removing dirty socks, let them air dry outside before tossing them into an old laundry basket. Once every few weeks, you can then wash all of the dirty socks in a single batch. Letting the dirty sock air dry before going into an old laundry basket will help to reduce or eliminate the smell so long as you wash all of the socks at least every few weeks. This will save water, eliminate the hassle of having to constantly clean socks, and you won't have to deal with a smelly bucket of wet, dirty filter socks.

Also, always rinse NEW filter socks before use in your tank to wash away manufacturing residue. You can use RO/DI water but tap water is probably fine as long as you let it dry before using it. If you forget to rinse a brand new filter sock, it will likely cause your protein skimmer to overflow because of the manufacturing residue on the filter material.  Should that happen, turn off your skimmer, run a fresh batch of carbon and do a water change.  24-48 hours later you can resume skimmer operation.