Well Cliff, I am fine with my algae levels, but I think I tolerate a lot more "mess" than some do.
I need to scrape algae from the front glass about once a week if I want the view to remain pretty nice. If I let it go 10 days or two weeks it starts to be thick enough to bother even me. (At about 10 days it gets thick enough that if I am trying to hand feed my pistol shrimp, which lives at the very rear of the tank, it is hard to tell his antennae from the sea grass--if that gives you an idea of how fast it gets how thick.)
I have very little (I would say zero) problem with algae over running or causing any harm to my corals or clams, but there is a fair amount of algae growing on the back and side wall of my tank (which I only clean a few times per year). It is more coraline algae than green algae, but it is probably almost 50-50. I have about three small spots with bubble algae on my liverock, but they haven't grown or expanded for weeks, which is a blessed mystery to me. Much of my homemade live rock is covered with a red fuzzy material that I call cyno, but could easily be a red algae of some kind. It is not slimey to the touch. My fish and snails clear occassional patches and most of the real live rock is dominated by coraline with much less of the red stuff, but if you like a crystal clear looking tank, my tank isn't likely to please. As I say, none of this seems to overrun the corals and the corals are all growing and spreading, so it may inhibit/slow growth some, but isn't really anything but "aesthetic" IMO.
Two places that might bother you more than the above are my overflow, which is often more like an "algae scrubber" system than just an overflow. An occassional snail gets in there, but otherwise nothing checks the growth of the algae but me. It is a black "built in" overflow, so the bottom half or so is very thick with coraline algae. I assume it is too deep (90 gal) for the light to get deep enough for good algae growth. The top 5 or 6 inches get pretty thick with at least three or four species of green algae that I pull out with my feeding forceps about once per week and really try to clean (including a razor to scrape off the glass) about every two weeks. When I clean the area out I fill a small plastic tub with water just so the algae comes off the foreceps and then grab "hunks" and drop them in the tub. Once I drain the tub into my sink and then throw the wet but drained algae into the compost it is easily 1/2 to 3/4 cup of algae removed per week, which is a lot more volume when it is still in the water column of the overflow.) You can't really see that area unless you are tall and look down into the overflow, so the fact that it is there doesn't really bother me.
The second place I am starting to notice some algae is on the blades of grass themselves. Many of them are starting to have short (1/8 inch) little "hairs" that are growing on the blade. Great habitat for amphipods and such, so as long as it doesn't really smother the grass, it is fine with me. It might really bother other folks.
One place I definitely have LESS algae is in the sump, which used to get a fair growth of hair algae that I needed to clean up about every 3 or 4 weeks to keep it from getting "out of control". I almost never need to remove any hair algae from the sump any more. I have one clump that still grows and needs to be pulled every few weeks, but it hasn't spread like it used to and, in moderation, is actually very pretty, IMO.
So, get that 125 out and start growing those grasses! If it gets really out of hand you can always tell visitors you are using the lights to make a great big vat of pea soup.
Have fun, whatever you do.
