{"product_id":"red-sea-salt-20kg-refill-box-600ltr","title":"Red Sea Salt 20kg Refill Box 600ltr","description":"\u003cp\u003e\u003cstrong\u003eOne 20 kg refill box mixes 600 litres of stable, moderate-alkalinity reef seawater.\u003c\/strong\u003e Red Sea Salt is Red Sea's original marine salt mix, formulated to a natural, reef-stable alkalinity so it suits fish-only systems and reef tanks running on natural or lightly dosed nutrient levels. This refill box is the format for topping up a bucket you already own, rather than paying for a new bucket each time.\u003c\/p\u003e\u003ch3\u003eKey features\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eMakes 600 litres\u003c\/strong\u003e — one 20 kg box mixed to reef salinity (35 ppt), roughly twelve 50 L water changes.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModerate, reef-stable alkalinity\u003c\/strong\u003e — 7.7–8.1 dKH at 35 ppt, closer to natural seawater than the elevated alkalinity of Coral Pro Salt.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDissolves fast and clean\u003c\/strong\u003e, with no cloudy residue left once fully circulated.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRefill box format\u003c\/strong\u003e — less packaging than a bucket, and no empty bucket to store afterwards.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003ctable\u003e\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003ePack weight\u003c\/th\u003e\n\u003ctd\u003e20 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMakes\u003c\/th\u003e\n\u003ctd\u003e600 L at reef salinity (35 ppt)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAlkalinity at 35 ppt\u003c\/th\u003e\n\u003ctd\u003e7.7–8.1 dKH\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCalcium at 35 ppt\u003c\/th\u003e\n\u003ctd\u003e415–430 mg\/L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMagnesium at 35 ppt\u003c\/th\u003e\n\u003ctd\u003e1,230–1,290 mg\/L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePotassium at 35 ppt\u003c\/th\u003e\n\u003ctd\u003e375–395 mg\/L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFormat\u003c\/th\u003e\n\u003ctd\u003eRefill box — no bucket included\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\u003c\/table\u003e\u003ch3\u003eWhich pack size do I need?\u003c\/h3\u003e\u003cp\u003eWe stock Red Sea Salt in three pack sizes. Cost per litre doesn't scale with pack size the way you'd expect, so it's worth checking the numbers rather than assuming bigger is cheaper:\u003c\/p\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003ePack\u003c\/th\u003e\n\u003cth\u003eMakes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e10 kg bag\u003c\/td\u003e\n\u003ctd\u003e300 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e25.2 kg bag\u003c\/td\u003e\n\u003ctd\u003e750 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e20 kg refill box (this listing)\u003c\/td\u003e\n\u003ctd\u003e600 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003eThis refill box is priced for topping up a bucket you already own, not for the cheapest litre on the shelf — the 10 kg bag currently costs less per litre. If cost per litre matters most and you don't need the box format, it's worth comparing against the other two sizes first.\u003c\/p\u003e\u003ch3\u003eDosage and directions\u003c\/h3\u003e\u003cp\u003eMix into clean RO or RO\/DI water with circulation until fully dissolved — allow around 20 minutes. Aerate before use, and match temperature and salinity to your display before adding. Use freshly mixed saltwater promptly rather than storing large volumes of made-up mix.\u003c\/p\u003e\u003ch3\u003eSuitable for, and not suitable for\u003c\/h3\u003e\u003cp\u003eSuited to fish-only systems and reef tanks running natural or lightly dosed nutrient levels, where a moderate, stable alkalinity is preferable to an elevated one. Reef tanks with heavy calcium and alkalinity demand from fast SPS growth are usually better matched to Red Sea's Coral Pro Salt, which mixes to a higher starting alkalinity and calcium level.\u003c\/p\u003e\u003ch3\u003eCare and maintenance\u003c\/h3\u003e\u003cp\u003eStore the unmixed salt sealed and dry — moisture reaching the box before mixing throws off the mix ratio. Once mixed, use within a few days rather than holding large volumes of made-up saltwater on hand.\u003c\/p\u003e\u003ch3\u003eWarranty and delivery\u003c\/h3\u003e\u003cp\u003eSold subject to Red Sea's standard product guarantees, which apply in addition to your consumer guarantee rights under Australian Consumer Law. Ships as a standard parcel — no special freight handling required.\u003c\/p\u003e\u003ch3\u003eCommon questions\u003c\/h3\u003e\u003ch4\u003eDoes the refill box come with a bucket?\u003c\/h4\u003e\u003cp\u003eNo. It's designed to be decanted into a bucket or sealed container you already own, which is what keeps the cost per litre lower than buying a new bucket every time.\u003c\/p\u003e\u003ch4\u003eWhat's the difference between this and Red Sea Coral Pro Salt?\u003c\/h4\u003e\u003cp\u003eRed Sea Salt mixes to a moderate alkalinity, around 8 dKH, suited to fish-only tanks and naturally-run reefs. Coral Pro Salt mixes to a higher starting alkalinity and calcium level for reef tanks with heavier coral growth demand.\u003c\/p\u003e\u003ch4\u003eHow far does 600 litres actually go?\u003c\/h4\u003e\u003cp\u003eIt depends on your tank size and water-change routine — as a guide, that's around twelve 50 L water changes, or considerably more if you're only topping up a smaller system.\u003c\/p\u003e\u003ch4\u003eIs this the cheapest way to buy Red Sea Salt per litre?\u003c\/h4\u003e\u003cp\u003eNot necessarily — compare the current cost per litre for each pack size on the product page before deciding. Choose the refill box if you already have a bucket to decant into; choose the 10 kg bag if cost per litre is the deciding factor.\u003c\/p\u003e","brand":"RedSea","offers":[{"title":"Default Title","offer_id":54774151676195,"sku":"RED129","price":164.95,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0972\/7236\/5347\/files\/Red-Sea-Salt-20kg-Refill-Box.jpg?v=1782108693","url":"https:\/\/nicksaquariumoceanariumterrarium.com.au\/products\/red-sea-salt-20kg-refill-box-600ltr","provider":"Nicks Aquarium Oceanarium Terrarium","version":"1.0","type":"link"}