Prefilter material and fine filtration  as a separation layer between the mechanical and biological filter media This specially formed filter material is for use after the layer of EHEIM MECH or MECHpro. EHEIM FIX acts as a separation layer between the mechanical and biological filter media. This is where the larger dirt particles are trapped, thus removing them from the water before entry into the biologically functioning filter layers. To fit an EHEIM external filter, we also offer EHEIM coarse filter pads to achieve the same result.

Specifications

What this pack is. EHEIM article 2506751. They sell it by weight and we list it by volume: 250 g of FIX is the 5-litre pack. The other size in the range is 50 g. FIX is very light for its bulk, which is why the two numbers look so far apart.

Function: mechanical. EHEIM classify FIX as a pre-filter and fine filtration medium and record it as non-absorptive — it traps particles, it does not adsorb dissolved compounds, and it is not a biological medium in its own right.

Water type: suitable for fresh and marine water.

Reusable: yes. It washes out and goes back in.

EHEIM do not publish a pore size, a fibre specification or a service life for FIX, so we are not going to print one.

Setup & Use

Where it goes in the stack. EHEIM lay their media out as a sequence the water passes through: EHEIM MECH or MECHpro first, as the coarse pre-filter; then EHEIM FIX as the separating layer between the mechanical and the biological stages; then the biological media, where the bacteria live; and finally EHEIM SYNTH filter wool for the fine polish before the water goes back to the tank. Getting the order right is most of getting filtration right.

FIX is the separating layer. Its job is to sit above a layer of MECH or MECHpro and catch the coarser particles that get past it, so they never reach the biological media below. Take that layer away and the bio media silts up, which is the slow way to lose flow and the fast way to lose stability.

Cleaning. Rinse it out under running water when the flow starts to drop and put it back. It is a mechanical medium, so unlike the biological stages it can be washed thoroughly without penalty. Replace it when it will no longer rinse clean or has started to break up.

If you would rather use a pad: EHEIM also make cut-to-shape filter pads for their external filters that do the same job in the same position. Which one you use is a question of what fits your basket.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months’ remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Filter media and substrates carry no manufacturing or expiry date — their working life begins on first contact with water, not on the shelf.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number — or email us, if you would rather — and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.