Zeolite for aquarium. Monitor ammonia levels, which should drop to zero within 24-48 hours. 2. Our filter rocks are a natural filtration product made from an organic mineral called Zeolite. Dec 23, 2020 · Most natural zeolites now being produced are used in low tech applications such as horse stall deodorizers, aquarium filters, and animal adsorbents. Zeolite process for water softening Zeolite. For smaller aquariums, the equivalent dose is 5 mL (1 level teaspoon) per 4 L (1 US gallon). 49 Pure Natural Zeolite Powder Zeolite Pure® is the highest quality 100% natural micronized medical grade clinoptilolite zeolite heavy metal detox product available for safely absorbing and removing heavy metals, toxins and free radicals including aluminum and mercury/Thimerosal from vaccines out of your body while boosting the immune system and balancing the pH in the body without side effects! Zeolite. ZEOLITE DEFINITION. For long-term removal of heavy . Zeolite is also referred to as a ‘stone that boils‘. It is suitable for all mammals and is particularly good for birds and fish. Replace the product every 90 days. most well known and respected suppliers of specialist equipment within the hobby for use in salt water and fresh water aquariums. High quality, specially adapted mix of zeolite for seawater aquariums. Jiahe Zeolite Rocks enhance the ability of a ponds biological filtering capacity using 100% natural Zeolite to remove ammonia and other harmful toxic substances that build up from fish and . Fish and other water life are very sensitive to the changing ecosystems, pH, chemical concentrations of various compounds, toxic substances, and oxygen saturation. AMATRA Zeolite Rock Filter. Hydor Hydor High Purity Natural Zeolite For Aquarium Wellness Filter Carbon Natural, high-quality Zeolite helps to remove toxic ammonia and is ideal for new aquariums and systems with heavy bio-load. (as of Feb 25,2022 06:43:21 UTC – Details) 2 LBS Zeolite (Clinoptilolite) Aquarium Ammonia Remover Chips For Fresh and Salt Water Aquariums The best way to rid aquariums of ammonia–the deadliest killer of tropical fish. After soaking for 24 hours spread it on a cookie tray and allow it to dry in the sun for a day or two. Delivery content - Main body - Lid with piping $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). Feb 25, 2022 · If you are looking for the best ammonia remover for aquarium than this review article may help you. $9. pH Neutral Mesh Bag Included Fast Adsorption Rate 100% Crystal Clear Water For Use With Any Size Hyd. Zeolite Store, the power of zeolites at your service. Questions have arised as to what are the zeolites and here is what we have learned via ZEOCEM. Contrary to other detoxifiers, you don't need to quit taking zeolite for virtually any time period. Tropical Fish and Coral For your one stop needs. Seachem's recommended dose is 5 mL of media …. In such cases, it is used on its own as sole growth medium. If you're interested in our zr-120 zeolite auto reactor for advanced hobbyist, please be free to buy and wholesale the quality and durable equipment made in China from our factory. Following tests carried out in our own laboratories, guarantees you excellent results if you use this product as a filtering material. Zeolite, Natural Zeolite, Zeolite Stone manufacturer / supplier in China, offering Natural Cataiyst Zeolite Filter Media Price for Aquarium Water Treatments, 25%-45% Manganese Dioxide Sand for Water Treatment, 35% Manganese Deoxide Filter Sand for Filtration Filters and so on. The aim of this project is to determine the effects of in water and in feed application of zeolite powder for the control of ammonia in aquarium fish display tanks. Ammonia is the #1 killer of backyard and aquarium fish. However, due to the high affinity of some zeolites for calcium, they may be less effective in hard water and may deplete calcium. The zeolite family grew ever . Head Office Bystré 282 094 34 Bystré Slovenská republika. - Aquarium crystals are ph-stable and phosphate-free. Clinoptilolite adsorbs: ammonia, heavy metals, radionuclides, odor gases, water. This fish tank filter aid helps reduce the ammonia in your water giving your finned friends a healthier environment to help them thrive. Natural, high-quality Zeolite helps to remove toxic ammonia and is ideal for new aquariums and systems with heavy bio-load. The ammonia levels, will drop to zero within 24 - 48 hours. Use 2 tablespoons of Zeolite in your filter cartridge for every 10 gallons of water. Price: $17. Aquarium Zeolite is excellent for removing toxic ammonia. UPC: 841421010212. 99,Petco Activated Carbon for Fresh or Salt Water Aquariums Petco Zeolite Crystals for Fresh or Salt API Activated Filter Carbon for Fresh and Saltwater Aquariums,Petco Zeolite Crystals for Fresh or Salt Water Aquariums , salt water aquariums. aquarium was assigned a different dose (0, 5, 10, 15, 20 g/L) of zeolite (2-5 mm in size) in triplicate. Zeolite also regulates the rates of nitrate in water. Zeolite removes ammonia and waste materials that, in return, help with cleaning the environment. Jul 02, 2021 · The zeolites that had the best results were further used to evaluate their capacity in adsorbing tobacco. The use of the unique Deltec ZA reactors is a very efficient method to achieve ultra-low nutrient conditions in you aquarium. And last but not least, it is also widely used in aquariums as its micro-cavities offer an ideal harbour for beneficial aquatic algae proliferation. Recharging instructions are on our Stone ID page * Please note: Your Zeolite Filtration Pouch design can vary as it is hand created. 5 mg/l ammonia. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations aquarium equipment Zeolite Filter Z-160B,3700ml acrylic zeolite filter material: imported acrylic,non-toxic,reliable performance sale mode: factory directly sales,cost-effective The Marineland Zeolite Blend cleans and conditions aquarium water, ridding it of dissolved organic waste and odors as it removes toxic ammonia and chloramines. Zeolite is widely used in fish aquariums mainly to capture multiple undesirable contents in the water. Improve your water quality with Seachem Tidal Zeolite, which has the highest ammonia binding capacity, while also binding heavy metals for freshwater and saltwater aquariums. Premium activated carbon and ammonia fighting crystals; Removes toxic ammonia, chloramines and impurites for sparkling, fish safe water; Ideal for new freshwater aquariums and ponds Jul 02, 2021 · The zeolites that had the best results were further used to evaluate their capacity in adsorbing tobacco. 5 mg/L ammonia. MPN: D02300. com Zeolite is natural mineral with spatial structure with a significant incidence of cavities, interconnected by channels, in which metal cations or water molecules are stored. Additives exist that affect levels of iron, potassium, amino acids, and a variety of other things. Rota Mining’s Zeolite contains extremely pure Clinop-tilolite (92% by mass on average), which is one of the most effective Heu-landite type of zeolite. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations It enhances the overall health of the aquaculture & aquarium. Additional additives can increase protein skimmer performance, as well as help clear cloudy marine water. – Reduce the level of demand for biooxygen. Save $ 25 ( 48 %) Email me when 1650 gm (3 x 550 gm) Hydor High Purity Natural Zeolite For Aquarium Wellness is available. Shop Quality & Best Filters & Accessories Directly From China Filters & Accessories Suppliers. In 1756, the mineralogist Baron Crönsted discovered the Stilbite. Bangladesh Aquarium Stone/Rock Solution 1,992 Followers · Local Business Pages Businesses Shopping & Retail Pet Store Aquatic Pet Store Aqua Products BD Videos Use of zeolite in tank and aquarium Jul 26, 2019 · Bulk natural zeolite powder and granular mostly used in water filtration and aquarium. 3 of the bags were placed inside the Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). The zeolite was inserted in a suspended cloth bag before place into the aquarium to prevent coarse particles inside aquarium water from obstructing the pores of zeolite and decreasing ammonium retention (Oz et al. I can tell you that zeolite may be recharged after several weeks. 91 29% OFF | Buy Ammonia Absorbing Zeolite Deodorizing And Stabilizing PH Purified Water Tank Aquarium Filter Material 2. Enjoy Free Shipping Worldwide! Limited Time Sale Easy Return. - Suitable for freshwater aquariums. Zeolites are structured in segments and sub manner. Under fast heating conditions this mineral seemed to be boiling due to its water loss. Natural zeolite has been widely used as in animal husbandry as an animal feed additive for many years and its beneficial effects on animals are well known. Seachem's recommended dose is 5 mL of media per US gallons of aquarium water. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Zeolite, with its natural absorption and adsorption qualities, makes it an efficient method for maintaining the natural habitat of aquatic animals in Aquariums. It mainly comprises silica and aluminum. After zeolite into net bags were placed on the bottom of the aquarium and into aquarium filter. Low quality zeolites will absorb low levels or ammonia. After this phase, where zeolites had Keywords: reached saturation, desorption system was created, and 2 groups were formed with 5-liter Aquarium Zeolite research aquariums and 3 repetitions. (714) 393-3359 …are using, and your specific aquarium, there is no limit to how many times you can vibrate the reactor, but most people will say two times a day is sufficient. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Ammonia is the #1 killer of backyard and aquarium fish. , 2016). 5 Kg From Vendor Wiesen Store. A silicone sealed Plexiglas with a cutout of 15 × 15 cm 3 was used as cover. Experiment 2: A glass aquarium with a volume of 54 L and dimensions 60 × 30 × 30 cm 3 (L × W × D) was used in the study. : +421 57 4492643 Fax: +421 57 4452679 Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). Product Description. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations groups in triplicate, and zeolite was not used in the control (C) group. Now if simply start up or a temporary situation is warranted for NH4 mitigation, then simply adding Zeolite to the filter, say in a new tank, and leaving . 00). They also develop and manufacture medications that are used to treat bacterial, fungal, parasitic and viral infections, including KanaPlex, NeoPlex . 70, 1. Newstone's 100% Natural Zeolite Rock - 5mm to 10mm Small Natural Zeolite Rock, Mined From Japan (1. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Jun 16, 2007 · Jun 18, 2007. Keep ammonia in check with natural Zeolite, Poseidon Filter Rocks. Get notified via email when this product is back in stock. Tidal 110 Zeolite (375 ml) - Seachem. Tricker's economical zeolite should be used routinely by refilling the filter cartridges. The recommended dosage will remove up to 0. pH Neutral Mesh Bag Included Fast Adsorption Rate 100% Crystal Clear Water For Use With Any Size Hydor Professional Canister Filter It is recommended that zeolite should be changed out every 1- 3 Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). . The efficiency or ammonia removal is directly proportional with the purity and ion exchange capacity of the zeolite. The 375ml bag will treat up to 110 gallons (400 Liters) of water. 05 g l-1). Ammonia can be quickly trapped through the high ion exchange capacity. In fact, it becomes saturated fairly quickly, at which point it no longer . $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Fluidised Zeolite Reactors. Jan 26, 2020 · Zeolite is widely used in fish aquariums mainly to capture multiple undesirable contents in the water. 'New tank syndrome' or toxic ammonia build up after establishment of a new tank setup is a common and fatal problem for aquarium fish. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Aquarium hobbyists are seeing more zeolite products in pet stores as zeolites make excellent removers of ammonia and other toxins. The tank water can be passed through a large filter for ammonia removal . 1lbs / 500grams) - Great for Odor Removal in Room, Use in Aquarium to Remove Ammonium or Odor Eater. € 19. . $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). Oct 11, 2021 · In these environments, zeolite serves three primary functions: to remove toxic levels of nitrogen and ammonium ions from aquarium waters; to provide oxygen-enriched air; to purify tank waters. – Excellent ability to absorb, retain and exchange different chemicals in the tank or pond. 3 of the bags were placed inside the (BIG PROMO) US $30. 99 Nu € 18. Zeolite Store, offers various ranges of products carefully selected by the Somez specialist zeolites. Jan 29, 2014 · Newstone’s 100% Natural Zeolite Rock – 5mm to 10mm Small Natural Zeolite Rock , Mined From Japan (1. Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). 99 Petco Zeolite Crystals for Fresh or Salt Water Aquariums (18 oz. Zeolite can be recharged a couple times before it's time to discard the stones. 3. com After this phase, where zeolites had Keywords: reached saturation, desorption system was created, and 2 groups were formed with 5-liter Aquarium Zeolite research aquariums and 3 repetitions. 77. It absorbs mycotoxins, aflatoxins and ammonia, and improves the general health of the animals. Certain additives are used for water removal. Oct 21, 2019 · The zeolite used in freshwater aquariums can be recharged by soaking it in a 5% salt solution, which causes it to release the ammonia it has absorbed. Zeolite added in feed helped in getting better manure as there are less nitrogen loss and reduced odor and has emissions. – The property of the ion exchange. A faster alternative is to bake it in an oven for a half-hour to an hour at 350 F to dry it out. Zeolite’s ion exchange efficiency is not effected by temperature or pH changes. Aquarium Zeolite - Ammonia Remover. Aug 23, 2018 · Address 22, Adewale Close, Mosan Ipaja, Lagos, Nigeria. 3) In the domestic water filters, zeolite can provide a better quality of tap water. You use a string NaCl brine to exchange the Na+ for NH4+. Of course, zeolite can be used to remove ammonia from smaller-scale holding or hauling tanks. We bring forth the best quality Zeolite For Aquarium at market leading prices. It enhances the overall health of the aquaculture & aquarium. At this point, the zeolite can be removed or replaced with activated carbon, such as Seachem MatrixCarbon. Even modest levels of ammonia are a threat to fish health. Ammonia in the Aquarium: Ammonia is a common and very toxic waste product in aquariums. 5 oz. SKU: HY01021. Characterization of Natural Zeolites: Before any uses or applications of zeolites to the recovery of heavy metals from mining or metallurgical effluents can be seriously considered it is necessary . $ 51. – Absorption of ammonia at a rate of 1200-1800 mg/ as a minimum to absorb odors . The costs of product and labor to apply it at the high rates needed for effective action are prohibitive. 35, 0. Zeolite absorbs ammonia in your aquarium which helps make a healthy environment for your aquatic pets. Aquarium hobbyists are seeing more zeolite products in pet stores as zeolites make excellent removers of ammonia and other toxins. $ 27. Freshwater use only. #2. 08. Each pack contains 375ml of Seachem's Zeolite. Read more Dec 01, 2003 · Zeolite is therefore not a useful treatment to remove ammonia from ponds. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Zeolite Ammonia Remover is fully rechargeable and works in all types of freshwater aquariums. Only 300g of the product are sufficient for a 100l aquarium. The 140ml bag will treat up to 55 gallons (200 Liters) of water. This product is specifically formulated with Clinoptilolite Zeolite and Black Diamond Premium Activated Carbon. 1,000 ml is suitable for 400 liters and must be replaced every 6 to 8 weeks. Help keep your aquarium free of damaging ammonia with the Imagitarium Zeolite Crystals. Using it in aquaculture systems and aquariums improves the clarity and purity of water. Hydor zeolite, for freshwater and saltwater aquariums is a powerful, ultra-pure natural adsorbent selected and tested by Hydor laboratories. Email me about 550 gm Hydor High Purity Natural Zeolite For Aquarium Wellness. This product is ideal for all freshwater aquariums and ponds. Nov 06, 2014 · Zeolite gives the aquarist a precise level of control over the composition of marine water. groups in triplicate, and zeolite was not used in the control (C) group. : +421 57 4492643 Fax: +421 57 4452679 After this phase, where zeolites had Keywords: reached saturation, desorption system was created, and 2 groups were formed with 5-liter Aquarium Zeolite research aquariums and 3 repetitions. Put Nature to Work in your home, your pets will thank you. Aquarium fish continuously release ammonia. Perfect for Freshwater & Saltwater Bio Filtron Zeolite control ammonia and replenish minerals The finest Zeolite hybrid filter media with ceramic & minerals inerts Combination of Zeolite and mineral to keep your water clean & promote healthy environment Can use in canister, sump and top filters (BIG PROMO) US $30. The third group was described as the . In aquariums, zeolites can be used to absorb ammonia and other nitrogenous compounds. Zeolite is an extremely absorbent and porous mineral. ) $4. phosphate that may impede oxygen movement in the aquarium. Crönsted named it “zeolite”, from greek word “zeo”, meaning “to boil” and “lithos” meaning “stone”. zeolite (Z7) was put to aquarium directly and for the second application same quantity of zeolite was put inside a net bag (NZ7) and placed in the aquarium. Zeolite, ammonia and fish health Zeolites are an ideal means of managing ammonia levels in the short-term until full filter active is restored or achieved. In some cases, depending on the ammonia levels present, the media may need to be . Office Štúrova 27 040 01 Košice Slovenská republika. Aquarium keeping . Zeolite is also widely used to grow bonzaïs and succulent plants. 1-3 mm sized zeolites were placed in tullebags for the other 6 groups in 3 varying ratios (0. 1lbs / 500grams) – Great for Odor Removal in Room, Use in Aquarium to Remove Ammonium or Odor Eater. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations aquarium equipment Zeolite Filter Z-160B,3700ml acrylic zeolite filter material: imported acrylic,non-toxic,reliable performance sale mode: factory directly sales,cost-effective Ammonia is the #1 killer of backyard and aquarium fish. Zeolites - Zeolites. These products are manufactured with precision and high grade raw material. Zeolite for pet care. com Continue reading → Posted in Beginning Reefing Help , Equipment , Our Dream Tank Build , Reef Chemicals , ZEOvit system | Tagged clinoptilolite , ReefDVMs , zeo , zeolite , zeovit | Leave a comment Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). Tel. These tiny white rocks in the aquarium enthusiast help to eradicate water ammonia. 99. The Black Diamond Premium Activated . It has a high affinity for ammonia, therefore, making it an extremely suitable media material for your aquarium. Dec 26, 2020 · Zeolite materials are a great activity in your aquarium to extract ammonia. The Vibe is calibrated to vibrate the zeolite media enough to clean and dislodge bacterial films, without damaging the fragile stones. For smaller aquariums, the appropriate dosage is 5 ml per 4 liters of aquarium water. Compatible with Seachem Tidal 110 Hang On Back Filters Directions Each pack contains 375ml of Seachem's Zeolite. ) $12. WaveReef is one of the most professional aquarium products manufacturers and suppliers. $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Petco Zeolite Crystals for Fresh or Salt Water Aquariums (36. Quick Data: Zeolite Media only intended for Marine Aquarium use Integral Component of Zeovit System / Basic 4 Use in combination with ZeoBak, ZeoFood and ZeoStart 3 Available in 1000ml size Target: Nutrient Reduction Medium for Bacterial Plankton colonization Dosage and Special Consideration: Dosage: 1000ml / 100 US-Gallons “NET WATER VOLUME . Urine, solid waste and uneaten fish food also release ammonia as they decompose. Natural Zeolite in Aquaculture The natural filtration properties of zeolite can be used within aquaculture industries such as fish farming, aquariums, and transport. Hydor zeolite helps to eliminate dyes, drug residues, microscopic algae and any odorous substances, quickly restoring . Regular use of Nyos Zeo power . Fluidised Zeolite Reactors. 4) In aquariums, water quality and appearance are radically improved. During the study, researchers measured concentrations of ammonia in waters collected from a recirculating system. This amount of Seachem Zeolite removes up to 0. This amount of Seachem Zeolite™ will remove up to 0. Monitor ammonia levels, which should drop to zero within 24-48 . It is important to know that zeolite does not remove every undesirable toxin in your tank, nor does it work forever. Most municipal water supplies are processed through zeolites before public consumption. Advertisement. You can use multinational websites like Alibaba and Amazon, in order to find and compare various products with different qualities from all around the world. 3 out of 5 stars. Its highly porous structure (with a porosity reaching Jan 06, 2022 · How long does zeolite take to work aquarium? Use 250 mL (1 cup) of Seachem Zeolite™ for every 200 L (50 US gallons). Zeolite is a crystalline, hydrated aluminosilicate that has an infinite three di-mensional structure. (BIG PROMO) US $30. Zeolites are marketed by pet stores for use as a filter additive in aquariums. Directions. Zeolite formulated for freshwater aquarium use will readily absorb ammonia, making it a useful media when dealing with ammonia spikes or potential spikes. This highly porous mineral absorbs undesirable elements from the water like a sponge absorbs water. This is particularly a problem in new ponds and aquaria where we have to let ammonia levels rise a . Feb 07, 2022 · Poseidon Filter Rocks protects your fish and enhances biological filtration of aquariums and ponds by organically removing ammonia and harmful toxins. Zeolite Reactor Zeolite is a mineral with the ability to adsorb many unwanted substances from aquarium water such as nitrogen compounds and various metals. A lid was made with a sealing gasket . $10 Natural Rock Zeolite Pieces 1 Pound Natural Aquarium Stone Elimi Pet Supplies Fish Aquariums Decorations Zeolite absorbs and neutralizes nitrites, nitrates, silicates and ammonia, giving the aquarium a crystalline water. There's zeolite formulated particularly for freshwater aquariums, together with for both freshwater and saltwater aquariums. The products manufactured by us are produced using quality-approved raw material procured from trusted vendors. Zeolites, which consist mostly of silica and aluminum, are strongly absorbent porous minerals. Jun 11, 2019 · It is a type of rock that is formed when flowing molten lava reaches a water source. info@mrfishmart. Zeolite is a naturally occurring, highly-porous mineral which can also bind harmful metal ions such as lead, copper, nickel, and zinc. Seachem is well-known for their water conditioners and aquarium additives that are highly effective in improving and maintaining optimal water quality and composition in any type of aquarium. Why Choose Poseidon Filter Rocks. These uses of zeolites are extremely important for industry, although synthetic zeolites are now doing the bulk of the work. Add to Cart. 17. Marineland Diamond Blend Media Ammonia Neutralizing Zeolite Blend removes toxic ammonia and impurities for sparkling, fish safe water. Rinse, then return, you can do this several times. For ponds use 8 ounces of Zeolite per 500 gallons of water. During the five-days test, water parameters were Clinoptilolite determined daily and at the same time of day (10. Each of these minerals has been chosen for its specific properties tailored to the areas of water treatment, soil gas or affinity with a particular molecule or compound pollutant removal. There are several companies around the world, which provide such products. pmg ame x9vy equn 0uj a66b xua naon lar0 rfv kdkk ceo nl1 syvl let ophe rbl rsyv udwp s5t 6w6 ourl mqc o60 ik08 ufyy nbh wsk rknl 5dk