The coarse and the fine blue filter sponges house the most important bio - cultures, which are responsible to effectively clean the water. You should clean or replace one sponge at a time every 3 - 6 months to maintain the right biological balance in your aquarium.

Suitable for REKORD 70/90, RIO 125/180, VISION 180, DELTA 100. 

You may also want to consider the other Juwel Compact Sponges in the related products below.