{"product_id":"seachem-flourish-phosphorus","title":"Seachem Flourish Phosphorus","description":"\u003cp\u003e\u003cstrong\u003ePhosphorus is the nutrient planted tanks run short of first, and Seachem Flourish Phosphorus lets you correct it without touching nitrate.\u003c\/strong\u003e It's a concentrated potassium phosphate solution formulated for the Flourish planted-aquarium range, dosed to a target phosphate reading rather than a single fixed schedule. It suits any freshwater planted aquarium — high-tech CO2 tanks and low-tech alike — where plants are showing stunted growth or dark, phosphorus-starved leaves.\u003c\/p\u003e\u003ch3\u003eKey features\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTargeted phosphorus, no nitrate\u003c\/strong\u003e — corrects a phosphate deficiency without adding nitrate, so the two nutrients can be dosed independently.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDose to your test kit, not a guess\u003c\/strong\u003e — Seachem recommends adjusting the dose to a phosphate test result rather than dosing blind, because dosing without testing is the main cause of pest algae with this product.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision dosing formula included\u003c\/strong\u003e — for aquarists who want an exact phosphate increase rather than the standard maintenance dose.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConcentrated\u003c\/strong\u003e — every size treats water for under 1c per litre, and the cost per litre drops further as pack size goes up.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReported safe for shrimp\u003c\/strong\u003e — Seachem states it is safe for invertebrates such as shrimp when dosed as directed.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eSize\u003c\/th\u003e\n\u003cth\u003eBarcode\u003c\/th\u003e\n\u003cth\u003eApprox. litres treated per bottle\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e100 mL\u003c\/td\u003e\n\u003ctd\u003e000116019507\u003c\/td\u003e\n\u003ctd\u003e~3,200 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e250 mL\u003c\/td\u003e\n\u003ctd\u003e000116019606\u003c\/td\u003e\n\u003ctd\u003e~8,000 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e500 mL\u003c\/td\u003e\n\u003ctd\u003e000116019309\u003c\/td\u003e\n\u003ctd\u003e~16,000 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e2 L\u003c\/td\u003e\n\u003ctd\u003e000116019804\u003c\/td\u003e\n\u003ctd\u003e~64,000 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e4 L\u003c\/td\u003e\n\u003ctd\u003e000116019903\u003c\/td\u003e\n\u003ctd\u003e~128,000 L\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003cp\u003eActive constituent: potassium phosphate solution, supplying available phosphate (P₂O₅) 0.3% and soluble potash (K₂O) 0.2%.\u003c\/p\u003e\u003ch3\u003eWhich size do I need?\u003c\/h3\u003e\u003cp\u003eAll five sizes cost well under 1c per litre of water treated, and the cost per litre falls as the bottle gets bigger — the 4 L pack works out cheapest per litre treated, the 100 mL bottle the most expensive. Buy small if you're testing whether your tank needs regular phosphorus dosing at all; buy the 2 L or 4 L if you're already dosing weekly across a large or heavily planted system.\u003c\/p\u003e\u003ch3\u003eDosage and directions\u003c\/h3\u003e\u003cp\u003eStandard maintenance dose: 2.5 mL (half a cap) per 80 L, once or twice weekly, or as needed when plants show deficiency signs such as stunted growth or dark-green colouring. Seachem's own guidance is to dose against a phosphate test kit reading rather than a fixed schedule, targeting a phosphate level of roughly 0.15–1.0 mg\/L.\u003c\/p\u003e\u003cp\u003eFor a precise increase, Seachem publishes a dosing formula: 0.8 × tank volume in US gallons × desired phosphate increase in mg\/L = mL to dose.\u003c\/p\u003e\u003ch3\u003eSuitable for, and not suitable for\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eSuitable for freshwater planted aquariums, including high-tech CO2-injected setups and low-tech tanks.\u003c\/li\u003e\n\u003cli\u003eReported safe for freshwater invertebrates such as shrimp when dosed as directed.\u003c\/li\u003e\n\u003cli\u003eNot intended as a stand-alone fertiliser — most planted tanks also need a nitrogen, potassium and trace-element source; Seachem does not publish reef or marine dosing guidance for this product, so treat it as a freshwater planted-tank product only.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eSafety\u003c\/h3\u003e\u003cp\u003eA minor overdose is typically not harmful, but a large one can shift nutrient levels quickly enough to stress fish, plants and beneficial bacteria — measure doses rather than pouring by eye, and keep dosing tied to test results rather than a guess.\u003c\/p\u003e\u003ch3\u003eGoes well with\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/seachem-flourish-potassium\"\u003eSeachem Flourish Potassium\u003c\/a\u003e — corrects potassium deficiency, the nutrient most often short alongside phosphorus.\u003c\/li\u003e\n\u003cli\u003e\n\u003ca href=\"\/products\/seachem-flourish-trace\"\u003eSeachem Flourish Trace\u003c\/a\u003e — covers the trace elements this product doesn't supply.\u003c\/li\u003e\n\u003cli\u003eA phosphate test kit — needed to dose this product against a reading rather than a fixed schedule.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eWarranty and delivery\u003c\/h3\u003e\u003cp\u003eCovered by your rights under Australian Consumer Law in addition to any manufacturer guarantee. Ships Australia-wide from North Lakes, QLD.\u003c\/p\u003e\u003ch3\u003eCommon questions\u003c\/h3\u003e\u003ch4\u003eWill this cause algae?\u003c\/h4\u003e\u003cp\u003eOnly if it's dosed without testing. Phosphate is a plant nutrient, but oversupplying it relative to what your plants can use is a common cause of pest algae — dose against a test kit reading rather than on a fixed schedule alone.\u003c\/p\u003e\u003ch4\u003eDoes it add nitrate?\u003c\/h4\u003e\u003cp\u003eNo. It's formulated to supply phosphorus without nitrate, so it can be dosed independently of your nitrogen fertiliser.\u003c\/p\u003e\u003ch4\u003eIs it safe for shrimp?\u003c\/h4\u003e\u003cp\u003eSeachem states it is safe for invertebrates such as shrimp when dosed as directed.\u003c\/p\u003e\u003ch4\u003eWhat size should I buy first?\u003c\/h4\u003e\u003cp\u003eStart with the 100 mL or 250 mL bottle if you haven't dosed phosphorus before — it lasts a long time at the standard dose, and lets you confirm your tank needs it before committing to a larger pack.\u003c\/p\u003e\u003ch4\u003eHow is the dose measured?\u003c\/h4\u003e\u003cp\u003eBy volume against your tank size — 2.5 mL per 80 L as a maintenance dose, or Seachem's formula (0.8 × US gallons × desired mg\/L increase) for a precise target.\u003c\/p\u003e","brand":"Seachem","offers":[{"title":"100 mL","offer_id":55244169871651,"sku":null,"price":17.95,"currency_code":"AUD","in_stock":true},{"title":"250 mL","offer_id":55244169904419,"sku":null,"price":26.95,"currency_code":"AUD","in_stock":true},{"title":"500 mL","offer_id":55244169937187,"sku":null,"price":43.95,"currency_code":"AUD","in_stock":true},{"title":"2 L","offer_id":55244169969955,"sku":null,"price":150.95,"currency_code":"AUD","in_stock":true},{"title":"4 L","offer_id":55244170002723,"sku":null,"price":279.95,"currency_code":"AUD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0972\/7236\/5347\/files\/0198-flourish-phosphorus-2-l_9676e7e1-0f39-425e-9658-5b040b532521.png?v=1782710700","url":"https:\/\/nicksaquariumoceanariumterrarium.com.au\/products\/seachem-flourish-phosphorus","provider":"Nicks Aquarium Oceanarium Terrarium","version":"1.0","type":"link"}