Cloudy water isn't one problem — it's four different problems that look similar. Match your water's colour to the cause below and you'll fix it in days, not months.
White or milky water = bacterial bloom
Cause: excess nutrients — usually a new tank cycling, overfeeding, or a deep gravel clean that disturbed waste.
Fix: feed less, wait. Blooms exhaust their food and clear in days. In a new tank this is normal — don't restart. Persistent bloom = you're overfeeding (see our feeding guide for portions).
Green water = algae bloom
Cause: light + nutrients. Usually direct sunlight or lights running 10+ hours.
Fix: lights to 6–8 hours on a timer, tank out of direct sun, bigger water changes. A clean-up crew from our algae eaters and snails keeps surfaces spotless — full strategy in our algae control guide.
Yellow or brown water = tannins
Cause: driftwood or leaf litter releasing tannins.
Fix: only if you want — tannins are harmless (shrimp love them). For crystal water, add activated carbon and do regular changes; pre-soak new driftwood for 1–2 weeks.
Grey haze or floating particles = mechanical
Cause: fine debris the filter isn't catching — new substrate dust or an under-powered filter.
Fix: add fine filter floss to your filter, rinse new substrate before adding, vacuum gravel weekly.
A natural clean-up crew working clean gravel — shrimp and snails process leftovers before they can cloud the water.
The keep-it-clear routine
- 10–15% weekly water change, temperature-matched
- Feed only what disappears in minutes — overfeeding causes 90% of cloudy tanks
- Lights 6–8 hours on a timer
- Live plants to outcompete algae for nutrients
- Test water weekly — clarity problems usually show in the numbers first (see the water quality guide)
FAQ
Do clarifier products work?
They clump particles so the filter catches them — cosmetic, not a cure. Fix the cause or the cloud returns in a week.
My water is clear but smells — why?
Clear ≠ clean. Smell means organics building up — usually overdue water changes or something decaying. Test, change water, investigate: why does my tank smell?
Build your clean-up crew
The easiest clear-water insurance is biological: shrimp, snails and algae eaters working around the clock — all Sydney-conditioned, shipped with our Live Arrival Guarantee.
