{"product_id":"api-ph-down","title":"API pH Down","description":"\u003cp\u003e\u003cstrong\u003eA concentrated acid dose that moves pH down in millilitres, not capfuls.\u003c\/strong\u003e API pH Down is a sulfuric-acid-based liquid (under 10% by weight) that lowers freshwater aquarium pH for soft-water species such as tetras, discus and Amazonian community fish. It doses at 1 mL per 10 US gallons (37.85 L), sold here in 118 mL and 473 mL Professional Size bottles.\u003c\/p\u003e\n\n\u003ch3\u003eKey features\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSmall doses, real effect\u003c\/strong\u003e — 1 mL per 10 US gallons (37.85 L) is the full working dose; this is a concentrate, not a diluted conditioner.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwo bottle sizes\u003c\/strong\u003e — 118 mL for routine top-ups, 473 mL Professional Size for larger systems or frequent dosing.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUnder 1c per litre of treated water\u003c\/strong\u003e at API's label dose, on either bottle size.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFreshwater aquariums only\u003c\/strong\u003e — API does not rate this product for marine or reef systems.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCorrosive concentrate\u003c\/strong\u003e — this is an acid product (see Safety) and is dosed by millilitres, not poured freely.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhich size do I need?\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eBottle\u003c\/th\u003e\n\u003cth\u003eDoses at label rate\u003c\/th\u003e\n\u003cth\u003eApprox. water treated\u003c\/th\u003e\n\u003cth\u003eApprox. cost per litre treated\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e118 mL\u003c\/td\u003e\n\u003ctd\u003e~118 doses of 1 mL\u003c\/td\u003e\n\u003ctd\u003e~4,466 L\u003c\/td\u003e\n\u003ctd\u003eUnder 1c per litre\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e473 mL Professional Size\u003c\/td\u003e\n\u003ctd\u003e~473 doses of 1 mL\u003c\/td\u003e\n\u003ctd\u003e~17,900 L\u003c\/td\u003e\n\u003ctd\u003eUnder 1c per litre\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eBoth sizes work out to a fraction of a cent per litre of treated water at the label dose; the 473 mL Professional Size is the better buy per litre if you dose often enough to use it before you'd next need it. These figures are calculated from API's own 1 mL per 10 US gallon dose rate and each bottle's stated volume — API does not publish a pack yield figure itself.\u003c\/p\u003e\n\n\u003ch3\u003eHow much do I use?\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eAquarium volume\u003c\/th\u003e\n\u003cth\u003eDose at API's label rate\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e10 US gal (38 L)\u003c\/td\u003e\n\u003ctd\u003e1 mL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e20 US gal (76 L)\u003c\/td\u003e\n\u003ctd\u003e2 mL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e55 US gal (208 L)\u003c\/td\u003e\n\u003ctd\u003e5.5 mL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e100 US gal (379 L)\u003c\/td\u003e\n\u003ctd\u003e10 mL\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003eTest pH before adding another dose. API's guidance is not to move pH by more than 0.2 in any 24-hour period — dose, wait, retest, and repeat only if needed rather than chasing a target in one application.\u003c\/p\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003cth\u003eActive ingredient\u003c\/th\u003e\n\u003ctd\u003eSulfuric acid, less than 10% by weight\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eForm\u003c\/th\u003e\n\u003ctd\u003eLiquid concentrate\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eDose rate\u003c\/th\u003e\n\u003ctd\u003e1 mL per 10 US gallons (37.85 L)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eWater type\u003c\/th\u003e\n\u003ctd\u003eFreshwater aquariums\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePack sizes sold here\u003c\/th\u003e\n\u003ctd\u003e118 mL, 473 mL Professional Size\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaximum recommended pH change\u003c\/th\u003e\n\u003ctd\u003e0.2 per 24 hours\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eHazard classification\u003c\/th\u003e\n\u003ctd\u003eCorrosive — skin\/eye damage category 1A, corrosive to metals\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFreight\u003c\/th\u003e\n\u003ctd\u003eStandard\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eSuitable for, and not suitable for\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eSuitable for:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eFreshwater community tanks that need a lower, more acidic pH — tetras, discus, rams and other soft-water species\u003c\/li\u003e\n\u003cli\u003eGradual, tested pH correction alongside a KH (carbonate hardness) reading\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eNot suitable for:\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eMarine or reef aquariums — not rated by API for saltwater use\u003c\/li\u003e\n\u003cli\u003eHard, high-KH tap water as a permanent fix — the buffering will fight every dose; lowering KH is the underlying correction\u003c\/li\u003e\n\u003cli\u003eDosing at the same time as a pH-raising product — API warns this can cause erratic pH swings\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSafety\u003c\/h3\u003e\n\u003cp\u003eAPI's Safety Data Sheet classifies this product as corrosive: it may be corrosive to metals and causes severe skin burns and eye damage on contact. Handle it as an acid, not a conditioner:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eKeep in the original container, tightly sealed, out of reach of children\u003c\/li\u003e\n\u003cli\u003eWear eye protection and gloves when dosing\u003c\/li\u003e\n\u003cli\u003eFlush skin or eyes with water immediately on contact and seek medical attention\u003c\/li\u003e\n\u003cli\u003eNever add water to the concentrate; add the measured dose to tank water, not the reverse\u003c\/li\u003e\n\u003cli\u003eDo not dose at the same time as a pH-raising product\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eGoes well with\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/api-freshwater-master-multi-test-kit-5-in-1\"\u003eAPI Freshwater Master Multi Test Kit 5 in 1\u003c\/a\u003e — tests standard-range pH and KH, so you can see why a tank resists adjustment and confirm each dose has worked.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/api-ph-proper-6-5-powder-jar-240gm\"\u003eAPI pH Proper 6.5\u003c\/a\u003e or \u003ca href=\"\/products\/api-ph-proper-7-0-powder-jar-250gm\"\u003eAPI pH Proper 7.0\u003c\/a\u003e — a buffered powder that holds pH at a set point once pH Down has brought it into range, instead of one-shot dosing indefinitely.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWarranty and delivery\u003c\/h3\u003e\n\u003cp\u003eThis is a consumable, so no manufacturer warranty period applies. That does not affect your rights under the Australian Consumer Law: if the product is faulty, unsafe or not as described, you are entitled to a remedy.\u003c\/p\u003e\n\u003cp\u003eShips as standard freight. As a corrosive liquid, it travels in its original sealed packaging.\u003c\/p\u003e\n\n\u003ch3\u003eCommon questions\u003c\/h3\u003e\n\u003ch4\u003eCan I use API pH Down in a marine or reef tank?\u003c\/h4\u003e\n\u003cp\u003eNo. API rates this product for freshwater aquariums only. Marine and reef pH should be managed through the salt mix and buffering products designed for those systems.\u003c\/p\u003e\n\u003ch4\u003eHow much will one dose lower my pH?\u003c\/h4\u003e\n\u003cp\u003eAPI does not publish a fixed pH-per-mL figure because the result depends on your water's KH (carbonate hardness) — harder water resists the change more. Dose at the label rate, wait, and retest rather than assuming a fixed drop.\u003c\/p\u003e\n\u003ch4\u003eWhy does my pH keep drifting back up after dosing?\u003c\/h4\u003e\n\u003cp\u003eHigh KH acts as a buffer and pulls pH back toward its original point. If you're redosing frequently, testing and reducing KH is the more stable long-term fix rather than repeated acid dosing.\u003c\/p\u003e\n\u003ch4\u003eCan I use pH Down and pH Up together?\u003c\/h4\u003e\n\u003cp\u003eNo. API warns against dosing a pH-raising and pH-lowering product at the same time, as the two can cause erratic pH swings rather than settling at a stable point.\u003c\/p\u003e\n\u003ch4\u003eIs API pH Down safe to handle?\u003c\/h4\u003e\n\u003cp\u003eIt's classified as corrosive on API's Safety Data Sheet — it can cause severe skin and eye burns undiluted. Measure it carefully, avoid skin and eye contact, and always add it to tank water rather than adding water to the concentrate.\u003c\/p\u003e","brand":"API","offers":[{"title":"118ml","offer_id":54774195978531,"sku":null,"price":25.95,"currency_code":"AUD","in_stock":true},{"title":"473ml Professional Size","offer_id":55335272022307,"sku":"17163020301","price":75.95,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0972\/7236\/5347\/files\/APH161_4.png?v=1772082145","url":"https:\/\/nicksaquariumoceanariumterrarium.com.au\/products\/api-ph-down","provider":"Nicks Aquarium Oceanarium Terrarium","version":"1.0","type":"link"}