{"title":"Aquarium CO2 Regulators \u0026 Parts","description":"\u003cp data-start=\"142\" data-end=\"509\" style=\"text-align: center;\"\u003e\u003cstrong data-start=\"142\" data-end=\"192\"\u003ePrecision CO2 Regulators for Planted Aquariums\u003c\/strong\u003e\u003cbr data-start=\"192\" data-end=\"195\"\u003eAchieve consistent CO2 levels with our range of high-quality aquarium CO2 regulators. Designed for precision and reliability, these regulators (also known as pressure reducers) control the release of CO2 from your cylinder into the tank – supporting lush plant growth while keeping your aquatic environment stable.\u003c\/p\u003e\n\u003cp data-start=\"511\" data-end=\"747\" style=\"text-align: center;\"\u003eMany models include a built-in solenoid valve for easy integration into automated setups, so you can control CO2 dosing with confidence.\u003c\/p\u003e\n\u003cp data-start=\"749\" data-end=\"945\" style=\"text-align: center;\"\u003eWhether you're setting up a new tank or upgrading an existing system, you'll find durable, easy-to-adjust regulators for tanks of all sizes. Need help choosing? Our expert team is ready to assist.\u003c\/p\u003e","products":[{"product_id":"castle-dawn-aquatics-aquarium-co2-regulator-with-double-gauge-bubble-counter-w21-8-valve","title":"Aquarium CO2 Regulator with Double Gauge \u0026 Bubble Counter – W21.8 Valve","description":"\u003cp data-end=\"671\" data-start=\"307\"\u003eKeep your planted aquarium running efficiently with the Castle Dawn Aquatics Double-Meter CO2 Regulator, complete with a magnetic solenoid and integrated bubble counter. The dual gauge display enables you to easily monitor both tank pressure and output pressure at a glance, while the fine-tune needle valve ensures stable and precise CO2 delivery. Built with high-quality, pressure-resistant materials and a leak-proof design, this tank is ideal for serious aquascapers and planted tank enthusiasts.\u003c\/p\u003e\n\u003cp data-end=\"895\" data-start=\"673\"\u003e⚠️ \u003cstrong data-end=\"688\" data-start=\"676\"\u003eWarning:\u003c\/strong\u003e Cheap CO2 regulators sold on large online marketplaces may not meet safety standards. Poorly manufactured units can pose serious risks.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003eKey Features and Important Notes:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-end=\"914\" data-start=\"782\"\u003e\n\u003cstrong data-end=\"802\" data-start=\"782\"\u003eWhat’s Included:\u003c\/strong\u003e\u003cbr data-end=\"805\" data-start=\"802\"\u003e– 1 × CO2 Regulator (Double Gauge)\u003cbr data-end=\"842\" data-start=\"839\"\u003e– 1 × Built-in Bubble Counter\u003cbr data-end=\"874\" data-start=\"871\"\u003e⚠️ CO2 tubing and canister not included.\u003c\/li\u003e\n\u003cli data-end=\"1035\" data-start=\"916\"\u003e\n\u003cstrong data-end=\"941\" data-start=\"916\"\u003eDouble Gauge Display:\u003c\/strong\u003e\u003cbr data-end=\"944\" data-start=\"941\"\u003eView tank pressure and output pressure – instantly detect low gas or unsafe levels.\u003c\/li\u003e\n\u003cli data-end=\"1160\" data-start=\"1037\"\u003e\n\u003cstrong data-end=\"1065\" data-start=\"1037\"\u003eBuilt-in Solenoid Valve:\u003c\/strong\u003e\u003cbr data-end=\"1068\" data-start=\"1065\"\u003eA magnetically operated solenoid valve allows automated on\/off control when used with a timer.\u003c\/li\u003e\n\u003cli data-end=\"1263\" data-start=\"1162\"\u003e\n\u003cstrong data-end=\"1195\" data-start=\"1162\"\u003eFine Adjustment Needle Valve:\u003c\/strong\u003e\u003cbr data-end=\"1198\" data-start=\"1195\"\u003ePrecisely control CO2 output for stable and consistent injection.\u003c\/li\u003e\n\u003cli data-end=\"1403\" data-start=\"1265\"\u003e\n\u003cstrong data-end=\"1295\" data-start=\"1265\"\u003eHigh-Quality Construction:\u003c\/strong\u003e\u003cbr data-end=\"1298\" data-start=\"1295\"\u003eCrafted from pressure-resistant materials, these regulators have a longer life and superior durability over standard regulators.\u003c\/li\u003e\n\u003cli data-end=\"1512\" data-start=\"1405\"\u003e\n\u003cstrong data-end=\"1430\" data-start=\"1405\"\u003eAnti-Backflow Design:\u003c\/strong\u003e\u003cbr data-end=\"1433\" data-start=\"1430\"\u003eAn acrylic check valve prevents water from flowing back into the regulator system.\u003c\/li\u003e\n\u003cli data-end=\"1583\" data-start=\"1514\"\u003e\n\u003cstrong data-end=\"1523\" data-start=\"1514\"\u003eSize:\u003c\/strong\u003e\u003cbr data-end=\"1526\" data-start=\"1523\"\u003eStandard W21.8 thread (fits most UK and EU CO2 canisters)\u003c\/li\u003e\n\u003cli data-end=\"1630\" data-start=\"1585\"\u003e\n\u003cstrong data-end=\"1598\" data-start=\"1585\"\u003eWarranty:\u003c\/strong\u003e\u003cbr data-end=\"1601\" data-start=\"1598\"\u003e1‑Year Warranty (\u003cstrong\u003e\u003ca title=\"WARRANTY TERMS AND CONDITIONS - Castle Dawn Aquatics\" href=\"https:\/\/www.castledawnaquatics.com\/pages\/warranty-terms-conditions\"\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003eT\u0026amp;Cs apply\u003c\/span\u003e\u003c\/a\u003e\u003c\/strong\u003e).\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Castle Dawn Aquatics","offers":[{"title":"UK","offer_id":51082928324889,"sku":"000028L-1","price":39.99,"currency_code":"USD","in_stock":false},{"title":"US","offer_id":51082928357657,"sku":"000028L-2","price":39.99,"currency_code":"USD","in_stock":true},{"title":"EU","offer_id":51082928390425,"sku":"000028L-3","price":39.99,"currency_code":"USD","in_stock":true},{"title":"Other ( Please Leave a message)","offer_id":51082928423193,"sku":"000028L-4","price":39.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0036\/7679\/9046\/files\/Aquarium_CO2_Regulator_with_Double_Gauge_Bubble_Counter_W21.8_Valve_K-_1.jpg?v=1758455288"},{"product_id":"castle-dawn-aquatics-12v-co2-solenoid-valve-inline-magnetic-regulator-for-aquarium-systems","title":"CO2 Solenoid Valve – Inline Magnetic Regulator","description":"\u003cp data-end=\"679\" data-start=\"265\"\u003eThis compact and reliable CO2 solenoid valve is designed to provide safe, energy-efficient control over CO2 injection in planted aquariums. Crafted from corrosion-resistant aluminium alloy with a high-quality sealing ring, it ensures a leak-proof and long-lasting operation. Ideal for automating your CO2 system when paired with a timer, helping aquatic plants grow while keeping your setup safe and efficient.\u003c\/p\u003e\n\u003cp data-start=\"673\" data-end=\"895\"\u003e⚠️ \u003cstrong data-start=\"676\" data-end=\"688\"\u003eWarning:\u003c\/strong\u003e Cheap CO2 regulators sold on large online marketplaces may not meet safety standards. Poorly manufactured units can pose serious risks.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003eKey Features and Important Notes:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-end=\"819\" data-start=\"716\"\u003e\n\u003cstrong data-end=\"736\" data-start=\"716\"\u003eWhat’s Included:\u003c\/strong\u003e\u003cbr data-end=\"739\" data-start=\"736\"\u003e– 1 × CO2 Solenoid Valve\u003cbr data-end=\"770\" data-start=\"767\"\u003e⚠️ CO2 tubing, regulator, and timer not included.\u003c\/li\u003e\n\u003cli data-end=\"921\" data-start=\"821\"\u003e\n\u003cstrong data-end=\"834\" data-start=\"821\"\u003eMaterial:\u003c\/strong\u003e\u003cbr data-end=\"837\" data-start=\"834\"\u003eMade from aluminium alloy with high corrosion resistance and a durable sealing ring.\u003c\/li\u003e\n\u003cli data-end=\"1018\" data-start=\"923\"\u003e\n\u003cstrong data-end=\"945\" data-start=\"923\"\u003eEasy Installation:\u003c\/strong\u003e\u003cbr data-end=\"948\" data-start=\"945\"\u003eQuick to set up and compatible with standard 4\/6mm CO2 airline tubing.\u003c\/li\u003e\n\u003cli data-end=\"1133\" data-start=\"1020\"\u003e\n\u003cstrong data-end=\"1041\" data-start=\"1020\"\u003eEnergy Efficient:\u003c\/strong\u003e\u003cbr data-end=\"1044\" data-start=\"1041\"\u003eLow-pressure, low temperature design – safe DC input keeps power consumption minimal.\u003c\/li\u003e\n\u003cli data-end=\"1239\" data-start=\"1135\"\u003e\n\u003cstrong data-end=\"1164\" data-start=\"1135\"\u003eMagnetic Solenoid Design:\u003c\/strong\u003e\u003cbr data-end=\"1167\" data-start=\"1164\"\u003eReliable, waterproof coil provides stable operation and easy automation.\u003c\/li\u003e\n\u003cli data-end=\"1345\" data-start=\"1241\"\u003e\n\u003cstrong data-end=\"1257\" data-start=\"1241\"\u003eApplication:\u003c\/strong\u003e\u003cbr data-end=\"1260\" data-start=\"1257\"\u003eSuitable for planted aquariums, aquascaping setups, and aquatic plant growth systems.\u003c\/li\u003e\n\u003cli data-end=\"1417\" data-start=\"1347\"\u003e\n\u003cstrong data-end=\"1356\" data-start=\"1347\"\u003eSize:\u003c\/strong\u003e\u003cbr data-end=\"1359\" data-start=\"1356\"\u003eFits standard 4 mm inner \/ 6 mm outer diameter CO2 tubing.\u003c\/li\u003e\n\u003cli data-end=\"1464\" data-start=\"1419\"\u003e\n\u003cstrong data-end=\"1432\" data-start=\"1419\"\u003eWarranty:\u003c\/strong\u003e\u003cbr data-end=\"1435\" data-start=\"1432\"\u003e1‑Year Warranty (\u003cstrong\u003e\u003ca title=\"WARRANTY TERMS AND CONDITIONS - Castle Dawn Aquatics\" href=\"https:\/\/www.castledawnaquatics.com\/pages\/warranty-terms-conditions\"\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003eT\u0026amp;Cs apply\u003c\/span\u003e\u003c\/a\u003e\u003c\/strong\u003e).\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Castle Dawn Aquatics","offers":[{"title":"UK","offer_id":51082968858905,"sku":"000028L-1","price":21.99,"currency_code":"USD","in_stock":false},{"title":"US","offer_id":51082968891673,"sku":"000028L-2","price":21.99,"currency_code":"USD","in_stock":true},{"title":"EU","offer_id":51082968924441,"sku":"000028L-3","price":21.99,"currency_code":"USD","in_stock":true},{"title":"Other ( Please Leave a message)","offer_id":51082968957209,"sku":"000028L-4","price":21.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0036\/7679\/9046\/files\/CastleDawnAquatics12VCO2SolenoidValveInlineMagneticRegulatorforAquariumSystems.jpg?v=1753322460"},{"product_id":"castle-dawn-aquatics-co2-regulator-pro-extension-dual-manifold-block-add-on","title":"CO2 Regulator PRO Extension – Dual Manifold Block Add-On","description":"\u003cp data-end=\"673\" data-start=\"249\"\u003eUpgrade your CO2 Regulator with this manifold block extension, allowing you to run a second bubble counter and needle valve from a single regulator. Perfect for aquarists with multiple planted tanks, this extension enables precise CO2 distribution to two aquariums from one pressurised CO2 system. Built to high-quality standards with W21.8 threading, it's fully compatible with both domestic and European CO2 cylinders.\u003c\/p\u003e\n\u003cp data-end=\"895\" data-start=\"673\"\u003e⚠️ \u003cstrong data-end=\"688\" data-start=\"676\"\u003eWarning:\u003c\/strong\u003e Cheap CO2 regulator extenders sold on large online marketplaces may not meet safety standards. Poorly manufactured units can pose serious risks.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003eKey Features and Important Notes:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-end=\"852\" data-start=\"710\"\u003e\n\u003cstrong data-end=\"730\" data-start=\"710\"\u003eWhat’s Included:\u003c\/strong\u003e\u003cbr data-end=\"733\" data-start=\"730\"\u003e– 1 × CO2 Regulator PRO Manifold Extension Block\u003cbr data-end=\"784\" data-start=\"781\"\u003e⚠️ CO2 Regulator PRO, bubble counter, and needle valve not included.\u003c\/li\u003e\n\u003cli data-end=\"957\" data-start=\"854\"\u003e\n\u003cstrong data-end=\"879\" data-start=\"854\"\u003eDual Output Function:\u003c\/strong\u003e\u003cbr data-end=\"882\" data-start=\"879\"\u003eSplit your CO2 line to serve two aquariums from one pressurised CO2 source.\u003c\/li\u003e\n\u003cli data-end=\"1066\" data-start=\"959\"\u003e\n\u003cstrong data-end=\"992\" data-start=\"959\"\u003eFine Adjustment Needle Valve:\u003c\/strong\u003e\u003cbr data-end=\"995\" data-start=\"992\"\u003eDesigned for precise micro-adjustments. Not intended for full shut-off.\u003c\/li\u003e\n\u003cli data-end=\"1239\" data-start=\"1068\"\u003e\n\u003cstrong data-end=\"1094\" data-start=\"1068\"\u003eImportant Note on Use:\u003c\/strong\u003e\u003cbr data-end=\"1097\" data-start=\"1094\"\u003eAlways use the \u003cstrong data-end=\"1126\" data-start=\"1112\"\u003emain valve\u003c\/strong\u003e for complete shut-off. Do \u003cstrong data-end=\"1160\" data-start=\"1153\"\u003enot\u003c\/strong\u003e force the needle valve closed, as this may cause damage and void the warranty.\u003c\/li\u003e\n\u003cli data-end=\"1323\" data-start=\"1241\"\u003e\n\u003cstrong data-end=\"1266\" data-start=\"1241\"\u003eThread Compatibility:\u003c\/strong\u003e\u003cbr data-end=\"1269\" data-start=\"1266\"\u003eW21.8 × 1\/14\" – fits standard UK and EU CO2 cylinders.\u003c\/li\u003e\n\u003cli data-end=\"1418\" data-start=\"1325\"\u003e\n\u003cstrong data-end=\"1338\" data-start=\"1325\"\u003eMaterial:\u003c\/strong\u003e\u003cbr data-end=\"1341\" data-start=\"1338\"\u003eDurable metal construction for long-lasting, corrosion-resistant performance.\u003c\/li\u003e\n\u003cli data-end=\"1465\" data-start=\"1420\"\u003e\n\u003cstrong data-end=\"1433\" data-start=\"1420\"\u003eWarranty:\u003c\/strong\u003e\u003cbr data-end=\"1436\" data-start=\"1433\"\u003e1‑Year Warranty (\u003cstrong\u003e\u003ca title=\"WARRANTY TERMS AND CONDITIONS - Castle Dawn Aquatics\" href=\"https:\/\/www.castledawnaquatics.com\/pages\/warranty-terms-conditions\"\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003eT\u0026amp;Cs apply\u003c\/span\u003e\u003c\/a\u003e\u003c\/strong\u003e).\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Castle Dawn Aquatics","offers":[{"title":"Default Title","offer_id":51083149934873,"sku":"000028L-kl","price":26.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0036\/7679\/9046\/files\/CastleDawnAquaticsCO2RegulatorPROExtensionDualManifoldBlockAdd-On.jpg?v=1753325879"},{"product_id":"fish-tank-aquarium-co2-regulator-dual-output-two-bubble-counters-with-solenoid-gauge","title":"CO2 Regulator Dual Output – Two Bubble Counters \u0026 Gauge","description":"\u003cp data-end=\"671\" data-start=\"307\"\u003eThis premium dual-output aquarium CO2 regulator is perfect for aquarists running two tanks from a single CO2 cylinder. Made from high-quality aluminium, it features two precision needle valves and two bubble counters for accurate CO2 control. \u003c\/p\u003e\n\u003cp data-end=\"671\" data-start=\"307\"\u003eThe integrated solenoid valve allows easy connection to a timer, giving you complete control over your CO2 system’s schedule. Includes a built-in check valve and single pressure gauge for safe and stable operation.\u003c\/p\u003e\n\u003cp data-end=\"895\" data-start=\"673\"\u003e⚠️ \u003cstrong data-end=\"688\" data-start=\"676\"\u003eWarning:\u003c\/strong\u003e Cheap CO2 regulators sold on large online marketplaces may not meet safety standards. Poorly manufactured units can pose serious risks.\u003c\/p\u003e\n\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003eKey Features and Important Notes:\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli data-end=\"926\" data-start=\"782\"\u003e\n\u003cstrong data-end=\"802\" data-start=\"782\"\u003eWhat’s Included:\u003c\/strong\u003e\u003cbr data-end=\"805\" data-start=\"802\"\u003e– 1 × Dual Outlet CO2 Regulator\u003cbr data-end=\"839\" data-start=\"836\"\u003e– 2 × Bubble Counters\u003cbr data-end=\"886\" data-start=\"883\"\u003e⚠️ CO2 tubing and cylinder not included.\u003c\/li\u003e\n\u003cli data-end=\"1028\" data-start=\"928\"\u003e\n\u003cstrong data-end=\"952\" data-start=\"928\"\u003eDual Output Control:\u003c\/strong\u003e\u003cbr data-end=\"955\" data-start=\"952\"\u003eIndependently regulate CO2 to two aquariums using the dual needle valves.\u003c\/li\u003e\n\u003cli data-end=\"1121\" data-start=\"1030\"\u003e\n\u003cstrong data-end=\"1060\" data-start=\"1030\"\u003eIntegrated Solenoid Valve:\u003c\/strong\u003e\u003cbr data-end=\"1063\" data-start=\"1060\"\u003eEasily connect to a timer for automated on\/off CO2 dosing.\u003c\/li\u003e\n\u003cli data-end=\"1219\" data-start=\"1123\"\u003e\n\u003cstrong data-end=\"1148\" data-start=\"1123\"\u003eSingle Gauge Display:\u003c\/strong\u003e\u003cbr data-end=\"1151\" data-start=\"1148\"\u003eClearly shows working pressure at a glance to monitor system status.\u003c\/li\u003e\n\u003cli data-end=\"1309\" data-start=\"1221\"\u003e\n\u003cstrong data-end=\"1246\" data-start=\"1221\"\u003eBuilt-In Check Valve:\u003c\/strong\u003e\u003cbr data-end=\"1249\" data-start=\"1246\"\u003ePrevents water backflow into the regulator and CO2 cylinder.\u003c\/li\u003e\n\u003cli data-end=\"1392\" data-start=\"1311\"\u003e\n\u003cstrong data-end=\"1332\" data-start=\"1311\"\u003ePrecision Tuning:\u003c\/strong\u003e\u003cbr data-end=\"1335\" data-start=\"1332\"\u003eSet 1 bubble every 2–3 seconds with reliable consistency.\u003c\/li\u003e\n\u003cli data-end=\"1493\" data-start=\"1394\"\u003e\n\u003cstrong data-end=\"1417\" data-start=\"1394\"\u003eHigh-Quality Build:\u003c\/strong\u003e\u003cbr data-end=\"1420\" data-start=\"1417\"\u003eMade from corrosion-resistant aluminium alloy with a durable finish.\u003c\/li\u003e\n\u003cli data-end=\"1590\" data-start=\"1495\"\u003e\n\u003cstrong data-end=\"1504\" data-start=\"1495\"\u003eSize:\u003c\/strong\u003e 10 × 15.5 cm (W × H) – 3.9 × 6.1 inches\u003cbr data-end=\"1547\" data-start=\"1544\"\u003e\u003cstrong data-end=\"1560\" data-start=\"1547\"\u003eWarranty:\u003c\/strong\u003e 1‑Year Warranty (\u003cstrong\u003e\u003ca title=\"WARRANTY TERMS AND CONDITIONS - Castle Dawn Aquatics\" href=\"https:\/\/www.castledawnaquatics.com\/pages\/warranty-terms-conditions\"\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003eT\u0026amp;Cs apply\u003c\/span\u003e\u003c\/a\u003e\u003c\/strong\u003e).\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Castle Dawn Aquatics","offers":[{"title":"Default Title","offer_id":51085781434649,"sku":"000028L-KI","price":36.5,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0036\/7679\/9046\/files\/CastleDawnAquaticsDualCO2reactor.jpg?v=1753354699"}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0036\/7679\/9046\/collections\/Castle_Dawn_Aquatics_Aquarium_CO2_regulators_Section.jpg?v=1753326347","url":"https:\/\/www.castledawnaquatics.com\/collections\/aquarium-co2-regulators-parts.oembed","provider":"Castle Dawn Aquatics","version":"1.0","type":"link"}