Ok im new to this but for my experience with algae scrubbers so far it seems to me that more people are having phosphates and nitrates issues with new guide line type scrubbers. Every body i seen that are using the per tank size in gallons scrubbers are not having any issues at all. If the guide lines are correct dont you think it should work everytime. for example in my 150 gallon tank i have a 9x6 screen made for 4 cubes and acording to the guide lines a 23w cfl bulb on each side suppose to work well in my case it didnt and for many more people didnt work either, it seems that you have to add 2 more 23w cfl bulbs to get nice green algae to grow and thats what most people tell you as soon as you post about your scrubber not working. Im not trying to talk crap about the new guide line i just have not seen a scrubber in person with the new guide lines fully stock with great success. the only tanks i seen successfully run by scrubbers has been the one using the old guide lines.