Write to support@aquahelm.com. One person reads it, so plain description beats a formal report.
The app sends nothing on its own, so a bug report only contains what you choose to write. What helps most:
Especially when the app's verdict disagrees with your judgement. Those are the reports worth the most — they are either a real bug or a wrong number in the species data.
The values you entered and the species in that tank. Without them a wrong verdict cannot be reproduced.
Which iPhone and which iOS, plus the app version from the bottom of Settings.
The built-in catalogue covers common freshwater species and will never cover everyone's tank. You do not have to wait for us: in the species picker, choose Add a species that is not listed, give it a name, and fill in only the requirements you are sure of. Anything you leave blank simply does not constrain the target range — a blank is better than a guess, because a guess produces warnings that are not real.
If you would like a species added to the built-in catalogue, send the name — the scientific one if you have it. Suggestions are read by a person and checked against sources before anything is added, because these numbers become advice about live animals.
Tell us, and say what you would set it to instead. The ranges are tolerances that get intersected across every fish in a tank, so one bad number can invent a conflict that is not there, or hide one that is.
Corrections from people who actually keep the species are the only way this data gets better.
Equipment inventories, warranty records, sales logs and maintenance diaries are out of scope on purpose. AquaHelm is meant to tell you what is wrong with your water, not to be a filing cabinet — and every extra thing it stored would be one more thing that could not be kept accurate.
Marine and brackish tanks are not supported yet.