Are you thinking that tap water is good enough for your reef tank?
At first glance, using tap might seem easier, and cheaper, but trust me when I say it’s not worth risking all those beautiful fish and corals you’ve worked so hard to care for!
Starting with pure RO/DI or distilled for your mixes and top-up water ensures fewer headaches down the road, and healthier marine life overall.
Why Tap Water Can Harm Your Reef Tank
Tap water contains several things that makes tap water safe for us to drink, but can actually be dangerous for the delicate life in your reef tank:
| Chlorine and Chloramine | These chemicals make our drinking water safe, but they’re harmful to fish and corals. |
| Phosphates and Nitrates | These feed unwanted algae. Too much algae can take over your tank. |
| Harmful Metals | Things like copper, zinc, and iron. Even tiny amounts can kill sensitive sea creatures. Especially bad for shrimp and snails. |
| Hidden Pollutants | Chemicals from factories, bug killers (pesticides), human medications. These can get into your local water supply. |
What Can Happen If You Use Tap Water
1. Algae Blooms
Tap water is full of fertilizer for algae which can quickly take over your tank and smother your corals.
2. Mysterious Deaths
Corals closing up for no reason? Are fish acting weird or dying suddenly? Tap water could be the culprit because its impurities stress out marine life.
3. Dull Coral Colors
Healthy corals are bright and colorful because they’re thriving in stable conditions with pure water. Impurities can dull their colors over time.
4. Water Chemistry Chaos
Marine tanks need consistent parameters to stay healthy, things like pH levels and salinity matter a lot! Using tap water introduces unknown variables that can throw everything off balance.
What Should You Use Instead?
So now that we’ve ruled out tap water for your saltwater mixes and top-ups, what’s the alternative? It’s all about starting with pure, clean H2O that you control from the start.
Reverse Osmosis (RO) or RO/DI Water
These systems remove almost all contaminants from the water, chlorine, heavy metals, nitrates, you name it! RO/DI units are highly recommended by experienced reef keepers because they give you complete control over what goes into your tank.
If buying a whole unit feels overwhelming at first (or pricey), there are smaller countertop options available too! Brands like Aquatic Life or SpectraPure offer beginner-friendly systems that work well for most setups.
Distilled Water
If you’re in a pinch, like I’ve been before, you can grab distilled water from the grocery store instead of using tap water directly. It’s not perfect long-term since it lacks minerals entirely (which means you’ll need a good salt mix to re-mineralize), but it’s way safer than untreated tap.
Pre-Mixed Saltwater
Some stores sell pre-mixed saltwater made with purified base water, a convenient option if you don’t want to deal with mixing salts yourself yet!
Products That Can Help
If you’re ready to invest in better options for your reef tank setup:
- Look into an RO/DI system like SpectraPure MaxCap or BRS 4 Stage Value Plus. They’re reliable choices many hobbyists swear by.
- A handheld TDS (Total Dissolved Solids) meter is great too, it tells you how “clean” your purified water is before adding it to your tank.
- For emergency situations when only tap is available (but please don’t make this a habit!), products like Seachem Prime neutralize chlorine/chloramine, but keep in mind this doesn’t solve heavy metal issues!
