What Is the Difference Between a Pond Sterilizer & a Pond Clairifier?

Ponds and Algae

• Every body of water has a different ecosystem. So the species of algae that thrive varies greatly from one pond to the next pond. Single-celled green algae (Chlorella vulgaris) are a sign of a healthy pond with a balanced ecosystem, and their presence indicates ample light and nutrients. The problem is that algae can make the pond water look unappealing. For example, planktonic algae, which form algae blooms that are common in ponds with lots of organic material, can turn the water green to greenish-brown. Algae blooms tend to occur more often during periods of drought in the summer months and can be killed by intense sunlight. Filamentous algae, such as those that form mats, typically are submerged under water, particularly in shallow areas of a pond. They appear during spring but may persist all year.

Clarifier and Sterilizer Descriptions

• A pond clarifier and a sterilizer use a UV filter to remove algae and bacteria from a pond. The UV filter works by passing water through a tube that is positioned next to a UV bulb. Algae cells can pass through a conventional filter unharmed, but a UV filter disturbs their internal structure. Although that may not kill the algae cells, it causes them to clump, making them easily trapped and broken down by the filter. A pond clarifier and a sterilizer each is highly effective in controlling algae blooms but does not have as much success with filamentous types of algae.

Difference

• A pond clarifier and sterilizer essentially perform the same function, which is to remove algae. They differ in how fast water flows through the tube to the filter. Algae cells are easier to kill than other microorganisms, such as bacteria and viruses. So the water can pass through the tube at a faster rate and still be effective. Other microorganisms must pass through slowly in order to be killed. A clarifier has a higher flow rate than a sterilizer so usually kills only algae cells, although it may kill some bacteria. A sterilizer removes other organisms that might harm the pond as well, but the water moves more slowly in a sterilizer.

Sterilizers vs. Clarifiers

• A pond clarifier typically does not remove bacteria and other harmful organisms. It controls algae in a larger area of water than a pond sterilizer, however, because the slower the water passes through the tube, the smaller the pond size it can control effectively. A pond sterilizer will kill algae and harmful bacteria, but it does not discriminate in what it kills, and so beneficial bacteria may be killed as well as algae. A pond sterilizer, however, kills only bacteria floating in the water; anything that is attached to rocks or plants remains unharmed.