Every reef tank hits rough patches. The difference between a panicked tear-down and a quick fix is knowing what you're looking at and what to do next.
Red slime (cyanobacteria) is usually the first crisis new reefers face. It thrives on excess nutrients and low flow. Fix it by increasing flow to any dead spots, reducing feeding, and running a refugium or carbon dosing. Chemi-Clean works as a last resort, but solve the root cause or it comes right back.
Aiptasia anemones spread from hitchhiker frags. Kill them with Aiptasia-X or a dedicated peppermint shrimp before they take over. Never try to rip them out — broken pieces regenerate into dozens of new pests.
Rapid Tissue Necrosis (RTN) on SPS corals almost always traces back to an alkalinity crash or swing. Test immediately, stabilize alk to 8 dKH, and frag the healthy tissue to save the colony. A two-part dosing pump prevents this from ever happening again.
Algae blooms in new tanks are normal — they're called the 'ugly phase' and last about three months. Don't panic, don't chase low nutrients, and don't add more chemicals. A clean-up crew of snails, hermits, and a tuxedo urchin will work through it naturally.