Ciculation is Key
July 19th, 2007 | by Thomas Belknap |There is no shortage of “key concepts,” involved in reef aquarium building. In fact, there are so many, it’s hard to know until you see the results of your ignorance. That is never fun.
But one concept which is much more important to reef aquariums than it is to most any other type of aquatic environment is circulation of the water. I say this because, in most cases, there is very little in the water other than fish to block the flow of water. In a reef tank, you obviously have the reef rock to contend with.
And what’s more, you won’t just be laying down your reef rock once: chances are, as you get the tank settled, you’ll need to move the rocks quite a few times. Every time you do this, you’re going to need to take circulation into account.
Our personal experience with this came with a fairly significant encroachment of Red Slime Algae. This particularly annoying pest is definitely one worth its own post or three, but suffice it to say that the only cure that worked was a chemical that we needed to add to the water. When we did that, we dumped it in front of the power head to let the chemicals spread throughout the tank.
But unfortunately, one corner of the tank was utterly and obviously without current, and the Red Menace persisted in that corner. Now, it is the farthest reach in the tank from the power head, so to some extent, this should be normal. However, adding to that problem is the fact that we had live rock more or less wedged right into that corner. We didn’t mean to, we’d just needed to do some adjusting after a recent change, and hadn’t noticed how close the rock was to the glass.
So until we made some adjustments to the rock’s location, that corner continued to have Red Slime. But more importantly, that side of the tank might otherwise have continued to lack current. That means less nutrients and oxygen for corals that might otherwise grow there, and in general less life in that corner of the tank. Also, that section of the tank could accumulate waste ammonia and cause a problem farther down the line. I don’t know for sure, but I’ll betcha that there are some nasties that could grow in such an environment also; I’m thinking that an abundance of anaerobic bacteria might gather there.
So the lesson is clear: make very sure when you set your reef rock that you’ve determined where the water will flow and whether or not that circulation is going to work the way you thought it would. In fact, it might even be worth it to pick up half a handful of sand and drop it in front of the power head. Then you can see from the movement of the silt whether or not the full tank is getting the circulation it needs. Just be sure to blow the rocks off when you’re done with a turkey baster or something.
