How Often to Change Filter Socks and Roller Mats
Posted by Gallery Aquatica on
Filter socks and roller mats catch waste before it breaks down into ammonia and phosphate, but they only work while they are actually catching things. Leave a sock in past its use-by point and it turns into a nitrate factory, dumping everything it trapped straight back into the water column. This is a numbers problem, not a feel problem, so here is a rough schedule based on micron rating and how heavily stocked your tank is, plus what it costs to run properly through a Brisbane winter of steady indoor temperatures and normal feeding.
What you need
- 200 micron filter socks (2 to 3 in rotation minimum)
- Spare mesh or a DYMAX roller mat cartridge if your sump runs one
- A bucket for rinsing and a stiff brush
- Notebook or phone reminder to track swap dates
Replacement frequency by bioload
| Bioload | Sock (200 micron) | Roller mat advance |
|---|---|---|
| Light (nano reef, few fish) | Every 3 to 4 days | Every 5 to 7 days |
| Moderate (mixed reef, regular feeding) | Every 2 days | Every 2 to 3 days |
| Heavy (fish-heavy or SPS dominant, high feed rate) | Daily | Daily or auto-advance setting |
Steps to get the timing right
- Check the sock daily by eye. If it looks grey and slimy rather than white, it is overdue, regardless of the schedule above.
- Rinse pulled socks in a bucket of freshwater, not down the sink, and let them dry fully before reuse. Bleach dip monthly if odour builds up.
- Rotate at least three socks so one is always drying while two are in play. This is the cheapest way to extend life without shortening intervals.
- For roller mats like the ones DYMAX sump systems use, set the advance to match the heavier end of your bioload band rather than guessing.
- Log every swap for two weeks. Once you see the pattern, you can set a recurring reminder instead of checking daily forever.
Rough running costs
A pack of 200 micron socks from the filter sock range runs in the 15 to 30 AUD bracket depending on size and thread count, and with three in rotation you are replacing the set every four to six months under moderate bioload. Roller mat cartridge stock works out similarly per month once you account for how much mat gets used per advance cycle. Either way it is a small line item next to a skimmer or a heater like the Eheim Thermocontrol 300W, but skipping it costs you water quality, which costs more in the long run through stressed corals and extra dosing.
If you are setting up mechanical filtration from scratch, a full filtration setup paired with a compact all-in-one like the Waterbox Peninsula Mini 25 gives you sock or mat stages already built into the sump baffles, which makes rotation a lot less fiddly than retrofitting one into an older tank.
Related reading: our guide on general aquarium maintenance covers the rest of the weekly checklist this fits into.
Prices mentioned are accurate at the time of publishing and are subject to change. Check the relevant product page for the current price before ordering.