pulse69 Posted January 22, 2004 Share Posted January 22, 2004 Hi, I've been looking on reef forums as I am in the process of setting up a 3ft reef tank (dont worry I still have my 6ft african tank ). During my research on these forums, I have found that reefers use a refugium as a method of nitrate and nutrient export, meaning they rarely perform water changes as they are no longer necessary. This method of filtration has only become common place over the last couple of years. What is it? Basically they have another tank hanging off their sump which water flows through. In this tank they have macroalgae (really big algae) growing. This algae absorbs excess nitrates and disolved organics from the water and uses it to fuel its growth. The macroalgae is regularly harvested to remove the nitrates from the system. Basically its a natural filtration system. sounds pretty cool to me. Now my question is - has anyone tried to set this up for themsleves with plants in place of macroalgae? has it worked? If so, this could spell the next era of filtration for freshwater tanks too! martin Link to comment Share on other sites More sharing options...
searlesy Posted January 22, 2004 Share Posted January 22, 2004 There is no reason why it wouldnt work, I know Andy was going to set up a tub with a 250w MH over it for just this purpose. If you stocked it full of something relatively fast growing, and easy to harvest, such as Java moss, you could just chuck it out when you prune, or you could grow something a little more desireable, and perhaps make a bit of money for your effort. A refugium though, dosent negate the need for water changes, it just keeps your water cleaner between changes, and may perhaps allow you to have longer between changes if the need arises. The method has been employed as a wastewater treatment technique for a long long time, using natural or artificial wetands/reedbeds to strip the nutrients from wastewater before discharge to a waterway, or before reuse for irrigation. Link to comment Share on other sites More sharing options...
PHL Posted January 22, 2004 Share Posted January 22, 2004 I've read a report of this being used in a big freshwater setup using a rather large but low tank (more pond like) in another room, and using fast growing plants. An interesting part was the lighting was counter cyclic to the main tank, so that one or the other tank will be lit all the time, to maximise O2 and CO2 usage. A smaller tank was also placed in the centre to act as a breeding tank (ideal as water quality etc was exactly the same). Water change, although rare, must still be done, as there are still accumulated waste that are not removed by plants. And te sizes were rather big, so I don't think this would be a common practice (something like 100G main tank, and 20G secondary). Link to comment Share on other sites More sharing options...
CThompson Posted January 22, 2004 Share Posted January 22, 2004 If I remember correctly, a refugium is more than just an area where macroalgae grows. If a reefer has an area where only algae grows they refer to it as an “algae turf scrubber”. A refugium is an areawere indeed plant life is found, but moreover it is an area separated from the main tank (as a algae turf scrubber is), and has a host of invertebrates that live and breed in safety from predation. As time goes on, and the invertebrates increase in numbers (which they do in excess), they go “with the flow” and some end up in the main tank as food. Obviously very beneficial to the more delicate and fussy of the marine feeders. Either an algae turf scrubber or a refugium (which I take it is some deviation of “refuge”) as mention DOES NOT remover the need for water change, it just means the water stays in better condition between changes, as was so well said. They are however, I don't believe, "rare", just not as frequent.... Craig Link to comment Share on other sites More sharing options...
Peter_Gun_Riff Posted January 22, 2004 Share Posted January 22, 2004 they also use them to feed heir saltwater fish. Link to comment Share on other sites More sharing options...
DanceswithDingoes Posted January 23, 2004 Share Posted January 23, 2004 Just to further what Craig was saying, in an algal scrubber you still have to 'harvest' the algae to remove the nitrates and phosphates as the algae only traps it, it doesnt convert it. If you have an African setup then perhaps a plenum would be worth investigating, look up the "Jaubert" method on your reefing site but keep the dsb (deep sand bed) at 6-7cm rather than 6 inches. These have been used in nanno-reefs with months between water changes. Link to comment Share on other sites More sharing options...
Brett4Perth Posted January 23, 2004 Share Posted January 23, 2004 I don't see that an algea scrubber/refugium really adds much to a planted tank, unless you have a lot of vegetarian fish that are going to eat all of your plants (koi). You might as well grow the plants in your tank and "harvest" them from there. Cheers Brett Link to comment Share on other sites More sharing options...
trofius Posted January 24, 2004 Share Posted January 24, 2004 we used a system similar to this at uni in the aquaculture recirculating system, we had 10 400liter tanks pretty heavily stocked (1000's of fry )with silver perch flowing through sand filters and into a macrophyte bed. the macrophyte bed was about 4 meters in diameter 1meter high,( outside ) and had heaps of weed in there, elodea, but changed this to floating weed water cabbage???, which we thinned out every week, nitrites ammonia etc was allway like 0000, even after 6 months without a water change!!!!! just a float valve for top up when water evaporated... Link to comment Share on other sites More sharing options...
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