ISTA CO2 External Reactor

Specifications

• Type: inline CO₂ reactor with a ceramic diffusion tube and a patented impeller
• Hose connection: 12/16 mm (13 mm) filter hose
• Filter flow rate: suits 600 to 1000 l/h
• CO₂ inlet: 4/6 mm CO₂ tubing
• Body: transparent chamber, acid-resistant and dimensionally stable
• Mounting: external, inline on the filter return; can also be run inside the tank

The impeller is what separates this from a plain inline diffuser: it breaks the bubbles up and holds them in the chamber long enough to dissolve, so very little reaches the tank as visible mist.

What’s in the Box

Reactor body with the ceramic tube and impeller assembly, hose fittings and the manual.

Setup & Use

Cut into the return line from the canister filter, after the filter and before the tank, with the unit vertical and the arrow following the flow. Connect the CO₂ line from the regulator to the inlet.

Set the injection rate at the regulator, not at the reactor, and watch the bubble count through the transparent chamber. Start low, give it a week, and judge by a drop checker rather than by bubble count alone.

Strip and rinse the ceramic tube about twice a year — in tank water, or in dilute vinegar if it is scaled. A clogged ceramic raises back pressure and drops your filter’s flow before it stops dissolving properly.

Compatibility

Planted freshwater aquariums running pressurised CO₂ with an external canister filter. Takes 4/6 mm CO₂ tubing.

Fits 12/16 mm (13 mm) filter hose. It will not fit 16/22 mm hose without a reducer at each end, so check your filter’s hose size before ordering — EHEIM classic 250 and 350 are 12/16 mm on the return and will take it directly; the classic 600 and larger are not.

Safety & Precautions

Restricting the return line reduces filter flow. Check that your filter still turns the tank over properly after fitting, particularly on a smaller canister.

Fit it where a leak would not reach electrics, and check the hose joints for weeping for the first few days. Turn CO₂ off at night or on a solenoid with the lights — plants stop using it in the dark, and overnight injection is what crashes pH and suffocates fish.

Warranty & Support

This product is covered by warranty as per the manufacturer policy, against material and manufacturing defects from the date of purchase.

Warranty support is handled by us directly. Message our WhatsApp support with your order number and we will diagnose the fault first. Most cases are solved by replacing a single part, so you rarely need to send the whole unit. If the item does need to come back, it ships to our Delhi or Pune warehouse, whichever one served your order, and courier cost in both directions is borne by the customer. Your GST invoice is valid proof of purchase for the claim.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number, or email us if you would rather, and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.