Ada beberapa hal yang lupa saya masukkan di update terakhir. Yaitu tentang konsep refugium yang saya impikan, dan kutipan-kutipan berkesan dari survey data DSB.
Konsep Refugium:
Konsep refugium yang akan saya buat adalah tempat yang khusus untuk mahluk-mahluk mikro, filter feeder dan makroalgae.
Tujuan utama dari refugium ini adalah untuk menjaga populasi dari mahluk-mahluk kecil ini, sehingga ketersediaan pakan alami selalu terjaga. Baik yang hidup didalam sedimen pasir maupun yang di permukaan.
Untuk mencapai tujuan tersebut, dibuatlah setting sebagai berikut:
- Tank terpisah baik dari sump dan main tank.
- Input air dari ruang return pump-nya sump dan output air dari refugium keluar ke depan suction return pump.
- DSB setinggi 10cm, dari pasir aragonite yang telah mengalami tiga kali proses saringan sehingga didapatkan butiran terhalus (kurang dari 1 mm).
- Penambahan pasir dari tank yang sudah running selama setahun di lapisan teratas DSB.
- Tidak mencuci pasir untuk DSB. Karena dari 2 kali apikasi DSB yang pernah saya lakukan (satu tanpa dicuci, dan satunya dicuci bersih dengan air tawar), yang menunjukkan tanda pertumbuhan infauna tercepat dan terbaik adalah yang tidak dicuci terlebih dulu.
- Penanaman makro algae dari jenis anggur hijau. Bertujuan baik sebagai filtrasi biologis (hususnya Nitrate) maupun sebagai tempat tinggal infauna.
- Tidak akan menambahkan mahluk-mahluk yang dapat menjadi predator bagi infauna (sand stirrer starfish, kuda laut, ikan-ikan benthic feeder, dll).
- Teknik pencahayaan reverse-daylight. Tujuannya menghemat listrik dan menangani fenomena penurunan PH di malam hari, dengan mengharapkan oksigen tambahan yang dihasilkan tumbuhan.
Kutipan-kutipan dari DSB:
TENTANG UKURAN PASIR:
In all of my discussions about sand beds I have made a point of specifying one particular parameter, that of the average size of sediment particles in the sand bed. Why should this one factor be so important? The answer simply is that sediment particle sizes determine the acceptability of the sediment to the organisms. Perhaps an example might illustrate this statement better. One of the common amphipods found along the west coast of North America is a species called Rhepoxynius abronius . This small bug has been investigated in some detail as an organism to use to test the toxicity of sediments, has been found to prefer sediments of a specific particle size, 0.113 mm in diameter. If given a choice, it will move to and live in sediments of that one specific size, not sediments 0.110 mm nor sediments of 0.115 mm, but only of that one size. If individuals are experimentally confined to other sediment sizes, they neither live as long, nor reproduce as well, nor tolerate stressful conditions as do individuals kept at the optimum grain size (Ott, 1986).
Most sediment-dwelling organisms appear to have similar precise preferences. However, most will also live at least marginally well in mixed-sediments with sizes around their optima, and most sediment particle size optima seem to be in the range of 0.050 to 0.200. Consequently I suggest a range averaging about 0.125 as a good compromise. It isn’t specifically the best for most infaunal species, but it will allow a diversity of species to live pretty well.
Sumber : http://www.ronshimek.com/deep_sand_beds.html
The surface area for bacteria and microalgae in live rock or on other surfaces is insignificant compared to the area in a sand bed four or more inches in depth.
Sumber : http://www.ronshimek.com/deep_sand_beds.html
Salah kaprah mengenai ‘sifting / stirring the sand’:
Within a week, you should notice bubbles in the sediment next to the glass indicating the sand filter is working, within a couple weeks small tube traces should be visible in places in the sediments near the walls, and small bug populations should be evident. After a two week wait – and more time is desirable – fish may be added. UNDER NO CIRCUMSTANCES SHOULD YOU ADD “SAND-SIFTING” ANIMALS SUCH AS BURROWING SEA STARS OR SOME GOBIES. These animals are “sifting” the sediment to eat the sand critters that you need to have thrive. From this point, gradually add more animals up to the desired level.
Sumber : http://www.ronshimek.com/deep_sand_beds.html
Masalah nyata dan masalah berdasarkan dugaan terhadap DSB:
More imagined than real problems bedevil keepers of sand beds. The imagined problems are proposed by people who are ignorant of the sand bed dynamics. Among these imaginary problems are accumulations of hydrogen sulfide and detritus, and the need for sifting. Hydrogen sulfide will indeed be formed in the lowermost layers of a deep sand bed. It will NOT migrate up through the sediments to poison a tank. Hydrogen sulfide is an amazingly toxic gas, but that toxicity is exceeded by its pungent rotten-egg odor. The gas will have an exceptionally strong odor, and will seem overwhelming at levels well BELOW toxic amounts. If you can smell this stuff without it literally taking your breath away, it won’t be at a harmful concentration. There is no real evidence to indicate that it may reach toxic levels in a deep sand bed.
Detritus build up in the sediment is another non-problem. If the sediment fauna is thriving, there will be a slight build up of fine detritus while the rest will be processed by the infauna. The final imaginary problem, the presumed need for sifting in a healthy sand bed, simply does not exist. Small organism movements “sift” the sand sufficiently. Any other sifting of a healthy bed will cause serious harm.
Sand beds recycle materials and export many of the excess nutrients in an aquarium. Some excess nutrients are mobilized by becoming soluble through metabolic processes and need to be exported either as harvestable macroalgae or animals, grown in the main tank or a sump.
The only real problem with a sand bed is the reduction in diversity as the bed ages. This is caused by extinction and replacement problems because the volume of our beds is simply too small for some species to generate self-sustaining populations. This is remedied, by purchasing a detritivore or recharge kit or two every year or so to give a boost to the fauna.
Sumber : http://www.ronshimek.com/deep_sand_beds.html
