Natural volcanic rock for biological filtration EHEIM LAV consists of volcanic rock and is a natural product. Its rough, highly porous surface structure provides the purification bacteria with very good colonization conditions. Because it is a natural product the granulate and small pieces in the packs are of different sizes. EHEIM LAV can be washed and reused. It is suitable for fresh and marine water.

Specifications

What this pack is. EHEIM article 2519751. They sell it by weight and we list it by volume: 5,050 g of LAV is the 5-litre pack. The other size in the range is 1,010 g.

Function: biological. EHEIM record LAV as a biological medium and as non-absorptive.

Material: natural lava rock, and nothing else. Because it is a natural product the granules and broken pieces in a pack are deliberately not uniform — EHEIM say so on their own page, so a bag with a mix of sizes in it is the product working as intended, not a quality problem.

Water type: suitable for fresh and marine water.

Reusable: yes, rinsed carefully.

EHEIM publish no porosity figure, surface-area figure or granule-size range for LAV. Lava is sold on structure rather than on an assay, and we would rather say that than quote a number we cannot source.

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.

LAV is a biological stage. It goes after the mechanical layers, where the water reaching it is already free of the coarse dirt that would otherwise clog the pores. Put lava at the front of a filter and you have made an expensive, hard-to-clean sponge.

Rinse it before first use. Broken natural rock carries dust. A rinse until the water runs clear saves you a cloudy tank on day one.

Never clean or replace all of the biological media at once. This is EHEIM’s own instruction and it is the single most common way a cycled tank gets broken. Rinse gently, do a part of the bed at a time, and use tank water rather than tap water if you can — the bacterial film is the product here, not the substrate it sits on.

In external filters, clean by basket. EHEIM’s own advice is that the basket system in their external filters, and the module system in the internal ones, exist precisely so you can clean part of the bed and leave the rest of the bacterial population untouched.

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.