The fine blue sponge lives in the lower Bioflow insert, where the tighter pore structure slows the flow and spreads it evenly across a very large surface. That is where the slower biological work happens. Juwel makes it without chemicals, so it leaves no residue in the water.
It clogs before it looks dirty. Fine foam channels — water finds the easy path through and the rest of the block stops doing anything — and there is no visual test for it. The published symptom is the water level dropping inside the filter housing, so check that weekly. And follow Juwel's rule: never replace all the blue filter media at once.
Where it goes
Lower filter insert. This is the only Juwel medium made in a One size, for the Bioflow One filter.
Choosing a size
- One — Bioflow One: Primo 60 LED 2.0, Primo 70 LED 2.0
- Medium — Bioflow M: Rio 125 / 180 / 240 LED, Lido 120 / 200 LED, Trigon 190 LED, Vision 180 LED, and the Primo 110 LED 2.0 (which takes M, not S)
- Large — Bioflow L: Rio 350 LED, Vision 260 LED
- XLarge — Bioflow XL: Rio 450 LED, Vision 450 LED, Trigon 350 LED
Replacement
Juwel's product page says nine to twelve months; the filter manual gives three to nine months.
The rest of the Bioflow range is in our Juwel collection.