Algae

One of the many reasons frustrated people give up the hobby of aquarium keeping is algae growth , and the inability to control its accumulation on the glass, decorations and substrate .
Algae need light and food to live. Too much of either, and algae can become a problem, an unsightly problem. In reef tanks, it can also be deadly to your corals, smothering the sessile invertebrates in where they rest, choking them off from light and flow, leading to their untimely demise.

In order to defeat algae and its unwanted presence, it must be understood that standing around and complaining about it as if it is a mysterious plague brought upon your hobby by some vengeful and angry God, is not going to contribute to the solving of the problem.

With low nutrient levels, excellent filtration, appropriate lighting intensity and photo periods, algae can and is controlled by most successful hobbyists.

Here some hints, I will divide these into four categories'

1. Freshwater fish and freshwater planted tanks. Water changes! water changes! water changes!. In a fish only system ,water changes done frequently and religiously are the best method of controlling ugly algae growth. Don't overfeed,don't overcrowd your tank, and do not rely on the ubiquitous Hypostomos plecostomus to eat every slimy last speck of gooey green evil.. Your light above the tank is really so we humans can enjoy the beauty of our wet finned charges, it is not a night lite or a homing beacon for lost tropical fish wandering home drunk after a night of bar hopping. Put it on a timer, cheap and easy, and have the light come on less than eight hours of the day. For planted tanks, the usually stocking and feeding rules apply as well, however keeping phosphate and nitrite levels low is even more important. Planted tanks typically have more intense lighting fixtures on them,thus more growth. I have found that using fast growing plants and top water plants such as water sprite and duckweed can make life a little simpler. Yes , trimming the water sprite and netting out the duckweed is tedious, but the reward is Worth it. The faster they grow and multiply, the less food for algae.
2. Pond's.... If you are going to put your pond in the open back yard with no cover over it and crowd it with too many and too large Koi...with insufficient filtration...your on your own when you ask me to help drain it and catch the fish so you can scrape the 4 inches of muck off the sides and bottom of the mess you created. A pond is really and outdoor open air aquarium( or is an aquarium an indoor pond?). All the rules of stocking feeding and regular maintenance apply.
3. Saltwater Fish tank...water changes wa.....you get it. Also aggressive protein skimming, appropriate lighting and feeding. As well as high quality(meaning low TDS) reverse osmosis water(RO) or deionized water(RODI) for salt mixing or top off. Sometimes snails , hermit crabs and mythrax crabs can be used but triggers, puffers and some wrasses will eat them. So, every couple weeks get your scrubby out and use it, then do a 25 % water change...
4. Reef tanks,,,again use the lowest TDS water you can, aggressive protein skimming( in my opinion the skimmer should cost more than the glass box), the addition of phosphate removing media, and "cleanup crews"Change your bulbs when you should, not when you want to.. Make a decision, is the a reef tank or a fish tank, nothing under 150 gallons can really be both. Stock a member of the bristle tooth tangs as one of your fish, They are hardy and useful. Above 1 inch and less than 3 inches seems to be best the size. Feed until your fish are full once a day. This will take some practice. Also remember than when you feed your corals, that counts as bio lode as well, contributing to the dissolved organic matter in the tank and potential algae growth. Whether it is a frozen food or off the shelf liquid food, it all counts.It is vital,as Barney Fife of the Andy Griffith said,"nip the problem in the bud".  Quik reaction to the potential problems is key. When hair algae or cyanobacteria first appear, act now!