Husbandry & Evidence Review – 5 September 2026
This older article has been retained for useful context, but its husbandry claims have been checked and corrected where necessary. For Frogfather’s current evidence-led position on water, use Water for Dart Frogs and Tadpoles UK (2026).
Introduction
Water chemistry matters in amphibian husbandry, but the correct water depends on the job. Low-mineral RO can be useful for misting equipment, whereas aquatic larvae and some water-contact systems may require appropriate ionic/mineral content. It is too broad to say that all unremineralised RO water is inherently harmful in every frog application.
This article now distinguishes misting water from egg/tadpole water and explains when remineralisation may be appropriate rather than treating it as a universal requirement.
What Is Reverse Osmosis (RO) Water?
Reverse osmosis is a filtration process that strips water of virtually all dissolved solids, including:
- Chlorine
- Fluoride
- Calcium
- Magnesium
- Iron
- Trace minerals
RO water contains very little dissolved mineral content. That does not make it automatically “too pure” for every use: the welfare relevance depends on whether the water is being used for misting, soaking, eggs, tadpoles or another system. Long-term aquatic larval rearing deserves particular attention to water composition.
Why Pure Water Can Be Dangerous for Frogs
RO water, when used alone, can lead to:
- Osmotic stress – cells swell or burst due to a lack of balancing minerals.
- Electrolyte imbalance – frogs cannot regulate hydration or nerve function properly.
- Potential physiological problems in inappropriate water systems — but these signs are non-specific and should not be attributed to RO/mineral content without broader assessment.
Anecdotes of losses following water changes cannot by themselves establish RO/mineral composition as the cause. Use measured water chemistry, species-specific evidence and the complete clinical/husbandry picture rather than assuming causation.
What Is Remineralisation?
Remineralisation means adding safe, amphibian-appropriate minerals back into RO water. It restores water hardness and essential trace elements.
Common products include:
- SaltyShrimp GH+ (for soft-water species)
- Seachem Replenish
- DIY mixes with calcium chloride, magnesium sulfate, and potassium
Always use a TDS meter (Total Dissolved Solids) to measure mineral levels. Most frogs do well in the 80–150 ppm range, but this varies by species.
How to Safely Prepare Water for Frogs
- Start with RO or distilled water.
- Add remineralising product, per the label or custom ratio.
- Check with a TDS meter — adjust if needed.
- Let water sit for 24 hours if using in misting or reservoirs (to reach equilibrium).
- Use consistently for misting, top-offs, and water bowls.
When to Use Tap Water
If your local tap water is low in chlorine and not too hard, you can:
- Dechlorinate it using a product like Seachem Prime or ReptiSafe.
- Mix it 50/50 with RO water to balance minerals naturally.
For species such as Theloderma corticale, use clean stable water appropriate to the species and rearing system. Frogfather does not claim that one RO-plus-mineral recipe is proven to be the universally safest option.
A Cautionary Tale
Frogfather previously experienced a Mossy Frog loss around a change involving fresh RO water. That experience prompted stricter water checks, but it was not a controlled investigation and cannot prove that lack of remineralisation caused the death. The practical lesson is to avoid abrupt, unmeasured changes and to monitor water chemistry appropriate to the species and use.
Recommended Products
✅ TDS Meter – check your water’s mineral levels.
✅ GH+ Replenisher – restores calcium, magnesium, and trace elements.
✅ Safe Water Storage – store water in clean, labelled containers.
✅ Digital Thermo-Hygrometer – track changes if water chemistry causes stress.
