Questions before you build.

It depends on the plants. Low-light plants like Anubias, Java fern and Cryptocoryne do well at roughly 20-30 PAR at the substrate. Carpeting plants and demanding stems generally want 50+ PAR, which usually also means CO2 injection. Running high light without CO2 and fertiliser is the most common cause of algae.

No. Plenty of beautiful low-tech tanks run without it. CO2 becomes worthwhile when you want fast growth, dense carpets, or red-pigmented stem plants. If you are running high light, CO2 stops being optional, because the plants cannot use the light without the carbon to match it.

Match the bar to the tank length, not the volume. Our Aurora bars have extendable brackets, so the 20in unit covers 20-24in tanks and the 30in covers 30-36in. If your tank falls between sizes, size up rather than down.

No. Pressurised gas cylinders are dangerous goods and cannot go by standard carriers. We sell everything except the gas: regulator, diffuser, drop checker, tubing and valves. Cylinders are cheap to source or refill locally at a welding supplier, homebrew shop or paintball store.

It measures dissolved CO2 indirectly. The 4dKH reference solution plus indicator turns blue at low CO2, green at roughly 30 ppm, and yellow when CO2 is too high. It lags real conditions by an hour or two, so read it as a trend rather than a live number.

Use an active aqua soil if you are growing rooted stem plants or keeping shrimp, since it holds nutrients and buffers pH downward. Use inert sand or gravel if you mainly keep epiphytes like Anubias and moss attached to hardscape, or if you want your tap water parameters unchanged.

We ship worldwide. Orders are packed within 1-2 business days, then delivery is 8-16 business days to Australia and New Zealand, 7-14 to the US and Canada, 9-20 to the UK and Europe, and longer to some other destinations — the full table by destination is on the Shipping & Returns page. Every order is tracked from dispatch. Stock ships direct from our supplier, which is why the windows are quoted in weeks rather than days. Freight is charged by weight, so one combined order costs materially less than several small ones.

Unused items in original packaging can be returned within 30 days for a refund or exchange. If anything arrives damaged or faulty, contact us within 14 days and we will replace it.