Closed Loop Pro
The free planner runs one build and forgets it. Pro remembers every build you make, exports it, filters the whole 87-species database at once, and emails you the weekend a water change is due. The teaching stays free; Pro is the tools on top.
Pro is in build. The plan and the pricing are set; the subscribe buttons switch on at launch.
Nothing that is free today moves behind Pro. All 108 guides, the full database, and the planner read stay free forever. Pro adds saves, exports, filters, calculators, and reminders: the tools a keeper who runs more than one system wants, and nothing a beginner needs to build a first tank.
Saved and shareable builds
Keep every build you plan, name it, and share a link. The free planner runs a build and forgets it; Pro remembers all of them.
PDF export
Export the full plan and the shopping list as a clean PDF to print or hand to a partner.
The advanced compatibility filter
Filter the 87-species database by more than one parameter at once: temperature and pH and hardness and setup together, not one at a time.
Water-parameter and stocking calculators
Compute the water change to hit a target nitrate, or the stocking a tank can carry, from the same database the planner uses.
A maintenance scheduler
Set a system up once and get an email that says test your parameters and change 20 percent of the water this weekend. Husbandry reminders, never animal-health advice.
The plans
A subscription earns its keep only if it keeps helping. The maintenance scheduler is the reason to stay: a build is finite, but the weekend reminder to test and change water is a standing reason, and it stays in husbandry language. This is ecosystem design, not veterinary care. If an animal is sick, contact a veterinarian who treats aquatic or exotic species.