My Green Pond

[Anthony]

Am I correct in thinking I should be using the "Clarifying" chart for sizing not the "Sterilizing"?

 

[Waterbug]

Once the water's ecosystem can not sustain the algae, for one reason or another, then it will "suddenly collapse", or die off; so, this might occur before you can fine tune UV if you are have issues with it.

Just to be clear, large algae blooms in large bodies of water have sudden die offs not from a lack of nutrients but most often from a lack of O2...which kills pretty much everything, certainly fish. It's not really the algae themselves. Even though lots of algae cells are being produced a lot are always ending their life cycle. So bigger the bloom the more dead cells decaying and using up O2. In a water garden with moving water this is rarely a problem and the algae will continue to grow unless something else kills it.

 

[Waterbug]

Am I correct in thinking I should be using the "Clarifying" chart for sizing not the "Sterilizing"?

Yes.

These two terms are just names for strength or killing power. Sterilizer means 99.9% of every live thing going into the filter comes out dead, assuming basically clear water. A kill rate below 99.9% would be called a clarifier and is good enough for algae.

 

[crsublette]

Just to be clear, large algae blooms in large bodies of water have sudden die offs not from a lack of nutrients but most often from a lack of O2...which kills pretty much everything, certainly fish. It's not really the algae themselves. Even though lots of algae cells are being produced a lot are always ending their life cycle. So bigger the bloom the more dead cells decaying and using up O2. In a water garden with moving water this is rarely a problem and the algae will continue to grow unless something else kills it.

Just to be clear split'n hairs here with semantics. O2 is definitely one of those primary elements mainly needed for certain organisms to live. Even though O2 does not match the technical definition of a "nutrient", O2 is definitely one of those required elements for aerobic aquatic life; for this reason, I would definitely include O2 as a main "nutrient" for algae. When water lacks this "nutrient", then algae dies.