Why hair algae loves a planted tank
Hair algae is a filament algae — long, soft green threads that wave from leaf edges, tangle through fine-leaved stems, and stitch themselves into moss. A planted tank gives it everything it wants when the balance tips: bright light running long hours, carbon dioxide that arrives in bursts or not at all, and plant food supplied in fits and starts. The plants, which should be outcompeting it, grow slowly when any one of those three wobbles, while hair algae seizes every spare ray and nutrient within hours. It often starts where flow is weakest and light strongest — the top of tall stems, the leaves nearest the surface — and a single drifting strand can seed a new patch.
Pull it out by hand, thoroughly
Manual removal is not optional groundwork; every thread left behind keeps growing. An old soft toothbrush twirled slowly through an infested stem gathers strands like candy floss, and fingers work for the rest — grip a thread at its base and ease it away rather than snapping it mid-length. Leaves that are mostly algae, especially on slow carpeting plants and mosses, are better trimmed out entirely, because the algae woven into them will outlast the leaf. Drop removed algae straight into a bucket rather than letting it float free, and finish with a water change that siphons up the fragments your work dislodged. A thorough first session takes time, but it resets the contest to one the plants can win.
Rebalance light, carbon, and plant food together
The three levers only work as a set. Put the light on a timer and trim the bright period back to a steady, moderate day; a tank lit in long, irregular bursts will grow hair algae at any intensity. If you run carbon dioxide, keep the rate consistent from day to day and ensure the diffuser is actually misting — a clogged diffuser silently starves plants while the light blazes on. Feed the plants on a regular schedule rather than in occasional big helpings, because starved plants stall and the algae takes their share; equally, do not stop feeding altogether in the hope of starving the algae, which is hardier than the plants you are trying to protect. Then wait: clean new growth at the stem tips is the sign the balance has turned.
A crew for the strands you miss
Some grazers genuinely eat hair algae. Amano shrimp pick through stems for hours and are the classic choice; young Siamese algae eaters take threads readily, though they lose interest as they grow and fill up on fish food. Rosy barbs will graze it too but may sample fine-leaved plants as well, so they suit some tanks and not others. Whatever you add, keep fish feeding lean — a grazer with a full stomach of flake is a grazer on strike. Snails, by contrast, mostly ignore hair algae, so a snail-heavy cleanup crew will not solve this particular problem.
If it outgrows your plants anyway
Threads returning within days of a thorough clean-out, on a tank with a steady timer and consistent carbon, usually point to sheer light intensity — a powerful light hung close over a shallow tank — or to decaying matter buried in the substrate feeding the water column. Plants melting while algae thrives deserve a closer look at whether the species planted actually suit the light and water you can offer, and an aquatic shop that keeps planted tanks can judge a cutting or a photograph quickly. Scheduling the weekly trim, timer check, and plant feeding as recurring duties in KinsLe's Care Teams keeps the balance from drifting back, with each completed task timestamped so a missed week shows before the threads do.