Water Quality

Goldfish Library

Yes. If not removed by periodic cleaning, it decomposes consuming oxygen, liberating various noxious gases and carbon dioxide as well as phosphates, which can be relied upon as a reasonable guage of background pollution levels. Phosphate testing has not come into vogue yet. In many instances, certain elements of your filtration system (water fall) will either blow off these noxious gases or remove them (carbon) - but in other cases it's a good idea to "pond-water-rinse" these pads or matts (or baackwash your bead filter) to remove apparent mulm accumulations instead of letting them remain in the water column to decay. A good frequency to do this would be every 4-6 weeks. Obviously if you overclean any media it will be more difficult for beneficial microbes which are responsible for nitrogen reduction to survive.

Best and easiest to clean filter

Food for Koi and Goldfish

Water test kits