I had to do some digging but I got lucky and found a link to the article I referenced in a previous post. Here it is: http://koiclubsandiego.org/library/green_water.php It is a thought provoking article and by testing some of the theories, I have observed results consistent with the theories. Again, no concrete proof and even the author concludes more work is needed but it does offer a viable alternative to the notion that green water/single cell algae is controlled by starving it of nutrients or light. To continue the discussion on the other topics, first let me say that my use of the word "silt" highlights another problem we face in our industry. We each use words and phrases that mean one thing to us and may mean altogether another thing to someone else. What you call a pond I might call a water garden and the next guy calls it a water feature. We need a standard terminology we all use so that our communications are more clear and concise. To make a point here, go ask a landscaper the difference between "dirt" and "soil". On this matter, there is some action being taken to address our lack of a standardized terminology. So when I used the word "silt", I did so as my own slang for the "crud" (should I define that word now? lol) that clogs the filter pads. This organic buildup and decomposing debris can and does clog the filter pads and also has the ability to coat and clog some media types such as lava rock, ceramic media, etc... if a condition exists where it is not agitated/cleaned (like the backwashing process in a bead filter). Again, all I am proposing is that some media types work at less than full capacity if they become debris covered. (there is a reference to this in the above article in regards to the algae killing process). Finally I am in total agreement on the point made on sizing filters, flow rates, etc... Who is responsible for creating these parameters? More importantly, who is responsible for verify the claims that are made? We have no way to compare apples to apples when it comes to most of the equipment we use since each manufacturer can create their own criteria used to justify filter sizing, flow rates, etc... Even a set of temporary standards that companies and contractors could follow voluntarily until a more formal set of standards was established would greatly improve our industry and lead to better installations across the board.