I recently answered a question through a pm on an online reef hobby forum about detritus control. This is a rather complex subject because the amount of detritus in marine reef aquariums vary from tank to tank. Detritus is an issue that every aquarium owner has to deal with from time to time, In order to control it you have to know what it is.
Detritus in our reef aquarium is for the most part and without going into specifics; Uneaten food and fecal matter. Now I could go into detail about what else detritus could be as far as mineral grains and what not but I want to keep this short and easily understandable. Since detritus for the most part is uneaten food and fecal matter it is organic in nature and therefore must be dealt with before it becomes a problem for your water chemistry or food for nuisance algae. Detritus in most cases looks like “dust” in many reef tanks. It will settle on rocks, sand and corals if not properly taken care of. A buildup of detritus in the reef tank will cause algae outbreaks and it will effect the reef’s water chemistry.
There are two things you can do when dealing with detritus. Both ways still lead to the same conclusion, that is, detritus removal.
1. Going with a bare bottomed reef tank with minimal live rock and a good amount of flow to keep detritus particles suspended. Blowing off your rocks from time to time and using a filter sock in your sump and/or mechanical filtration of some type will help remove detritus. Since reef tanks like these lack a sand bed, sucking out detritus and removing it in a system like this is vital as there are generally little to no detritivores that will clean it out for you. Having some detritivores will definitly help but they will not thrive without a proper refugium or sandbed.
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2. Buy detritivores such as cerith snails, spaghetti worms, bristleworms, amphipods, copepods, certain starfish and a whole host of other reef inhabitants that will pick up what your fish, corals and you leave behind. Most people opt for this option mainly because they like the look of a sandbed and appreciate the biodiversity in the reef tank. When using a sandbed in your reef tank it is still important to keep it free of detritus or to maintain your detritivore population.
thanks for the article! what is the best placement of laminar powerheads to ensure detritus is kept suspended and as much water exchanged between the main tank and sump? I often read about using powerheads at opposing corners of the aquarium pointing to each other. But I was also told this will create vortix in the middle preventing ‘dirt’ from the tank flowing to the sump?
The best placement really depends on how your aquascaping is and whether or not you are using a sandbed. I plan on blogging about laminar flow in the future becouse its very mis understood. I prefer to place powerheads opposing each other on a wavemaker. Some times its extremely turbulent, but this helps keep particles suspended longer. A vortex may not be a bad thing to have but would be difficult to create since our tanks live rock will block the current and reducing its strenght.
Thanks for the reply and advice. I bough a WaveBox which – is said – will help the de-sedimentation of the entire aquarium habitat plus provide natural water movement for fish and corals. The wavebox comes with a light sensor to switch off the wave generation at night. Would it not be more efficient for detritus removal to have the wavebox on all time? What is the reason for having to switch off at night?
Hi Marco,
There is alot of debate about wether or not we should turn down our wavemakers, powerheads, and overall current at night. Some people think that it gives the fish a chance to rest while other people say that the ocean doesnt “turn down” so why should we do it in our tanks. Now there are going to be quite times in the ocean but its not always at night. So its naturally up to you to decide what you want to do about your tank’s current at night.
I do not use a nighttime mode on my wavemakers and pwerheads. everyonce in a while all the powerheads will be off becouse of the wavemaker they are attached too. This is only for a few moments however.
Congrats on your wavebox, I have seen some of these in action and wow they are a great source of water movement.
The ABC of water dynamics: need a mentor for a good forum discussion
I’m not an expert in water physics / dynamics / properties – and this is my dilemma: To ensure optimal filtration – how can I be sure 100% of the salt water in the tank is “uniformly” flowing through the sump Vs. having water circulation “layers” which hinder proper exchange between tank and sump? From a water “property” viewpoint – does having a lot of water “movement” in the tank directly equate into homogeneous water “exchange” with the sump? (I have a Wavebox, Nanostream in addition to the sump return pump). To facilitate the discussion with a silly example: if I have a 100 G tank and a return pump rate of 500 G/hour, does this mean that each water “molecule” in the tank will go through the sump 5 times an hour, or – subject to the pumps orientation, tank landscape, etc. – certain layers of water might go through the sump more times than others causing disoptimzed water filtration ? Can you get into the extreme situation where circulating layers of water – due to strong currents – don’t commingle with the rest and always stay in the tank (hence preventing phosphate / detritus going into the sump to be collected by the skimmer?). Looking forward to some good feedback and advise
A good solution in addition to all your tips are filter socks. Sometimes when my sump gets too dirty I would just stir it up and let it go to the main tank and let it come down through the sock. This is, of course, the lazy way to do it.
Good Point John I forgot about the filter socks even though i use them all the time lol. In addition to the filter socks you could also use sponges around your pumps intake. I notice a lot of buildup on my mag drive’s sponges.