CalReact 5000D Calcium Reactor
RO-CR5000
Dual-chamber calcium reactor for stable alkalinity on demanding tanks. Key specs Dual chamber, large capacity Tank rating Up to 350g Brand Reef Octopus HYDROS compatible No
Or build it into a bundle — save up to 6% ↓What it is, and who it is for.
Dual-chamber calcium reactor for stable alkalinity on demanding tanks.
| Key specs | Dual chamber, large capacity |
| Tank rating | Up to 350g |
| Brand | Reef Octopus |
| HYDROS compatible | No |
Build around the CalReact 5000D Calcium Reactor.
It's already in your system below. Add the flow, filtration and dosing around it and the discount starts working — tiers climb as the build grows, and the reef meter fills with it.
Pick the right one, not the biggest one
The honest line-up from filtration. Most buyers reading this page should buy the middle column.
Asked before checkout
The questions our support inbox actually gets.
Does it ship quickly?+
Orders placed before 2 PM ET on a business day leave the same day. Tracking is emailed the moment the label prints.
What if it's the wrong fit for my tank?+
Return it. 30 days, no restocking fee, refund to the original payment method. Better: tell us your tank first and we'll spec the system for free — half of all returns are sizing problems.
Who handles the warranty?+
We do. Everything carries the manufacturer's warranty and we run the claim for you — one email to us instead of a ticket queue.
How does the bundle discount work?+
Add items in the bundle builder: 2+ items saves 5%, 3+ saves 8%, 4+ saves 12%, and 5+ saves 15% off the whole system, applied at checkout.