So, you have some nuisance algae making your tank look like the bad part of town. Your algae blenny is absolutely stuffed to the gills. You can't keep acropora. Well, Boo-Hoo, it is your fault. You have the power to fix it. Oh you don't know how? Well, let me tell you a bit about nuisance algae.
Most algae issues can be solved with the same few steps. That being said, you should first identify your particular strain of woe. I think that reefcleaner's algae ID page is the most new user friendly one out there. Please visit the ARC Links page for many more ways to ID algae if it is not there.
All algae problems can be solved in 3 steps:
1. Manual Removal
2. Removal by CuC
3. Elimination of Nutrients/Light
Get in there and take as much out as possible by hand. But wait, with some of these algae's (bubble/velonia is notorious for this) you will just end up spreading the algae more as it's spores go whizzing around your tank. Other algaes have holdfasts that will dig into your live rock and not let you get these rootlike structures out by hand. So what do you do?
Get a hard bristle toothbrush and rubberband it to a length of 1/4" tubing. Move as much as you safely can by hand. Then get in there with the siphon-brush and scrub that rock clean. I have also done this with a small wire brush on an item that has a serious hold on the rock.
Removal by CuC
Snails, Crabs and cucumbers... Oh My!! Check the reefcleaners link above to help identify a CuC member you can add that will take care of this algae. No one CuC member eats everything!!! For instance, as far as I can tell, no snails will eat bubble algae. But, my emerald crabs will power right through it. I avoid a lot of algae problems mainly by starting out with a diverse CuC so they eat the algae before it becomes a problem.
For my 90G:
3 Pepp Shrimp
10 Emerald Crabs
10 Large Nassarius
25 Small Nassarius
5 Fuzzy Chitons (I just love them)
Unknown number of mini ceriths
20 Florida Ceriths
15 Turbo/Turban snails
5 Mexican Turbos
1 Serpant star
1 Black Cuc
2 Algae Blennies
Remember to feed your CuC if it is this large . Yes, I like my CuC members on thier own.
Elimination of Nutrients/Light
Once you have the algae removed/being eaten you need to stop the food that let's it grow. Generally, better husbandry techniques are what is needed here. I will avoid going over filtration methods and instead reccomend you peruse the filtration articles in this Wiki. I do want to go over what you should to help eliminate an outbreak so the better husbandry practices can take hold.
3 day Algae removal process
This process is to help kick start your new dedication to your tank and the elimination of this nuisance algae. Think of it kinda like a crash diet for your tank. During these three days where you will not see your sea buddies, spend the time reading up on nutrient control and removal in marine aquariums. This wiki is a great place to start. You can also follow the links section on ARC as well.
For three days you will be doing the following:
1. Set your Skimmer to "skim wet." This will help it take out as many nutrients as possible.
2. Start with a 50% water change - Yes, 50% of your total water volume, including sump. Do this water change daily for all 3 days. Yes, this means you will change out 150% of your water volume in 3 days. Yes, this is to remove as many nitrates and phosphates as possible.
3. Turn off your lights - Yes... for 3 days. In Fact, cover your tank with towels so light does not get in. (without your lights on they will need the extra warmth anyways.)
4. Run GFO and Carbon through a reactor if available, a bag if not. This is to remove any remaining DOC after the large water changes.
5. Daily, take a half hour to an hour (during water changes is good) to remove any algae you can get your hands on. Make sure to look very closely for any dead critters or such.
After 3 days you should have a great start to your new animal husbandry techniques and a much reduced algae problem that will be easily fixed by lowering your feeding and making sure you run a tight ship in your tank.