Mention the word ‘algae’ to different marine aquarists and the reaction could be mainly one of two, a look of horror perhaps bordering on panic or a smile and a nod. It all depends.
To some aquarists algae is most definitely a foe. These aquarists are, in the main, novices who are gathering experience and have found out the hard way the consequences of over feeding, over stocking, or over lighting. There could even be a combination. One consequence is long hairy green stuff waving in the currents as though it is making fun of the suffering aquarist. Green filamentous algae can spread to such an extent it overgrows the whole aquarium! It seems to be hardy too, as even if the nutrient level is reduced the monstrous stuff seems to survive for quite a while. It takes the nutrients out of the seawater of course which is the only saving grace I can think of. No, there’s one more, which is that it is food for some fish. Nevertheless, it is not required in abundance.
Similarly, slime alga is a problem. This time it is like thin semi-solidified goo on surfaces which is capable of suffocating the life out of anything it covers, again definitely not required. Fortunately it can be siphoned out at routine seawater changes but tends to linger for a while.
So who smiles at algae? It has to be those aquarists who have control of their aquarium conditions. Seawater parameters are as they should be and not permitted to be anything else. Some of these aquarists use algae to combat other algae, which sounds like justice to me! For example, nitrate and phosphate are implicated in the growth of nuisance algae. The same nutrients are necessary to some decorative algae. So, take some decorative algae, such as the Caulerpa macro type, and grow it in reasonable quantity in favourable conditions. If the bad algae is being physically removed and the good algae is taking in nutrients and in favourable conditions, which will lose out? It is likely to be the bad algae. Many use the system and it is definitely helpful.
Have a look at the imported photo with this text. Is that some of the hairy stuff I see?
I’m going off track a little but remaining with algae. Here’s another positive for algae which could develop beyond the intended stated use in a few years. Hope it proves to be of huge benefit!