Care: Water - Fresh, Salt, & Why to Use a Dechlorinator

All about freshwater & saltwater - dechlorinators, salt, water bowls, and pool construction & maintenance.
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Care: Water - Fresh, Salt, & Why to Use a Dechlorinator

Post by HCADirectors » Wed Mar 13, 2013 2:11 pm

Links and Quick Reference Lists updated May 2017

Questions about anything on this page - or any question about water that is used with hermit crabs and their enclosure - should be directed to the [Water] section as a new topic. Updates to this page can be made by contacting any Administrator or Moderator.

The products listed here are not all the crab safe products that exist!! These are just the most common ones, and the brands that are mentioned the most. There are many more products out there that are safe. If you have questions about something, ask in Water before you use it.

Basics, Dechlor, and Freshwater

All hermit crabs should be provided with two types of water bowls in their enclosure – saltwater and freshwater. All species of crab are found within one mile of the ocean, and it’s theorized that they can and will make the trip to gather saltwater when they need it.

For Freshwater:
Step one – make sure that the water has no chlorine or chloramines in it (see below)

Step two – make sure the temperature isn’t extremely hot or cold

For Saltwater:
Step one and two - both of the above steps for Freshwater

Step Three – use a saltwater fish salt (NOT a hermit crab product) according to its directions (see below)

Chlorine and Chloramine

All water entering a hermit crab’s tank, or that is used for a final rinse on anything that goes into a hermit crab tank, should be dechlorinated before use. A dechlorinator removes the chemicals from tap and bottled water that would otherwise harm a hermit’s gills. These chemicals could also be toxic to drink depending on the levels in the water. Well water that has not gone through a treatment process does not contain these chemicals and can be used without worry so long as it's been tested and is safe for human use.

Chlorine is very simple to make safe – you can leave a bucket of water uncovered for 24 hours before using it, or bring water to a rolling boil for 5 minutes (cool completely before use), or you can use a commercial fish dechlorinator to make the water safe to use instantly.

Chloramine is a combination of chlorine and ammonia, and it is harder to get rid of. Leaving it sit or boiling it will not remove the harmful chemicals. The only way to make water treated with chloramine safe is to use a dechlorinator specifically made for removing chloramine and ammonia. It has to break the chlorine-ammonia bond, and then it has to neutralize both the chlorine AND the ammonia. Be cautious about the product you buy – some dechlorinators only remove the chlorine by breaking the bond, but leave the harmful ammonia behind – so make sure to read the labels carefully. It needs to say that it either neutralizes or removes ammonia, not just that it treats chloramine in general. You can use any of the regular chlorine/chloramine removers as long as you use a second product that is designed to remove ammonia.

Water filters will remove most of the chlorine and chloramine in the water, but not all of it, so a dechlorinator should still be used.

Chloramine is more commonly used with city water systems than chlorine these days due to the fact that it is so long lasting. If you are unsure what your tap water is treated with, call your water department and ask – it’s a common question since many fish keepers need to know this in order to keep their pets safe. When it comes to bottled water, it’s safer to assume that it contains chloramines.

Heavy Metals

All crustaceans, including hermit crabs, are sensitive to heavy metals that can be in tap and bottled water. Very small amounts that are safe for humans and other pets and are permitted in tap water could cause problems long-term due to a hermit’s long lifespan and extremely small size. Because of this, it’s recommended to always use a dechlorinator that also states that it removes heavy metals along with the chlorine and/or ammonia.

Slime Coat

Slime coat used to be something that was never recommended for use with hermit crabs, but over the years we've found that it doesn't seem to have any effect, and therefore is safe for use. For more information, please see JediMasterThrash's topic - [The Great Stress-Coat Experiment]. Please note that are different types of slime coat that are used - some are aloe, others use a slimy chemicals, and still others use an additive that helps to support the fish in growing their own.

Quick Reference

Each water conditioner removes different things, so here is a quick reference of the major dechlorinating products you can find at the pet store. Fish products are generally safer and cost lest, and they have do not have the extra additives that reptile and hermit crab water treatment products may contain. (Like dyes, or unnecessary minerals.) Remember that if you have chloramine in your water then you need a product that removes both chlorine/chloramine AND removes or neutralizes ammonia, or the water will not be safe.
  • Chlorine/Chloramine means that it removes chlorine and breaks the chlorine-ammonia bond only, it will not remove the remaining ammonia.
    Ammonia means that it also neutralizes that remaining ammonia.
    Heavy Metals means it neutralizes any heavy metals.
    Slime Coat is any type of slime coat.

AquaSafe Plus by Tetra- Chlorine/Chloramine, Heavy Metals, Slime Coat
AquaSafe for Goldfish by Tetra- Chlorine/Chloramine, Heavy Metals, Slime Coat
BettaSafe by Tetra- Chlorine/Chloramine, Heavy Metals, Slime Coat
AquaSafe for Glofish- Chlorine/Chloramine, Heavy Metals, Slime Coat

Prime by Seachem - Chlorine/Chloramine, Heavy Metals, Ammonia, Slime Coat
Betta Basics by Seachem - Chlorine/Chloramine, Ammonia
Gold Basics by Seachem - Chlorine/Chloramine, Ammonia
Safe by Seachem - Chlorine/Chloramine, Ammonia (concentrated powder)

NovAqua by Kordon- Chlorine/Chloramine, Heavy Metals, Slime Coat
AmQuel by Kordon- Chlorine/Chloramine, Ammonia
AmQuel Plus by Kordon- Chlorine/Chloramine, Ammonia

BettaPlus by Nutrifin- Chlorine/Chloramine, Heavy Metals

Aqua Plus by Fluval- Chlorine/Chloramine, Heavy Metals, Slime Coat

Pro-Dechlorinator by Kent- Chlorine/Chloramine, Ammonia, Heavy Metals
Pro-Ammonia Detox by Kent- Chlorine/Chloramine, Ammonia
Betta Bowl Essentials by Kent Marine- Chlorine/Chloramine, Ammonia, Heavy Metals

Tap Water Conditioner by Aqueon- Chlorine/Chloramine, Ammonia, Heavy Metals,Slime Coat
Shrimp Tank Plus by Aqueon- Chlorine/Chloramine, Ammonia, Heavy Metals
Ammonia Neutralizer by Aqueon- Chlorine/Chloramine, Ammonia

Water Conditioner by Top Fin- Chlorine/Chloramine, Heavy Metals, Slime Coat
Betta Water Conditioner by Top Fin- Chlorine/Chloramine, Heavy Metals, Slime Coat
Thrive Hermit Crab Freshwater Conditioner- Chlorine/Chloramine, Heavy Metals

Ammo Lock by API- Chlorine/Chloramine, Ammonia
Tap Water Conditioner by API- Chlorine/Chloramine, Heavy Metals
Stress Coat by API- Chlorine/Chloramine, Heavy Metals
Marine Stress Coat by API- Chlorine/Chloramine, Ammonia, Slime Coat
Goldfish Protect by API- Chlorine/Chloramine, Ammonia

AquaSafe by TetraFauna (for reptiles)- Chlorine/Chloramine, Heavy Metals
(Contains a different kind of slime coat for reptile skin.)

Jungle Labs Start Right- Chlorine/Chloramine, Heavy Metals, Slime Coat

Weco Dechlor- Chlorine, Heavy Metals

Aquatize by Exo Terra- Chlorine/Chloramine, Heavy Metals, Slime Coat

Betta H20 Conditioner by ZooMed- Chlorine/Chloramine, Heavy Metals
ReptiSafe by ZooMed- Chlorine/Chloramine, Ammonia, Slime Coat
(Contains a different kind of slime coat for reptile skin. Use the amount given in the directions for turtle and amphibians.)
Hermit Crab Drinking Water Conditioner by ZooMed- Chlorine/Chloramine, Heavy Metals, Ammonia
(Do not use the Salt version - it's not for use with freshwater, and it contains artificial dyes. It also does not contain the right kind of salt for thier saltwater- read below for more information.)


There are over 70 elements in sea water, and it’s important for the health of your hermit crab that they have access to the right kind salt water that contains all of them. Hermit crabs need this kind of ocean water in order to regulate their bodies and to make molting easier, and all hermit crabs carry around a mixture of brackish water in their shells at all times. Brackish water is the term used to describe salty water that is between ocean water levels of salt, and pure freshwater.

Salt sold specifically for hermit crabs do not contain all these elements, and some even have artificial colors and unneeded chemicals added to them that can be harmful. They are also mixed at too weak of a concentration to be helpful, and are normally drastically overpriced.

Also, do not buy what is sold as “Freshwater Aquarium Salt”. While the salt is safe for use with hermit crabs, it contains only a few elements rather than a full mix that is helpful to hermit crabs. The two major brands that are NOT the right kind of salt to buy are API and Doc Wellfish. These types of salt are not going to be helpful in the long run, but they are not harmful.

Never use table salt or human grade “sea salt” for the same reason. Also, salt for human consumption usually contains anti-caking and anti-clumping agents to make to make it flow freely from shakers, and these could be potentially harmful to hermit crabs.

The correct type of salt to buy is the kind sold in the saltwater fish section. The specialty “reef” salt that many of these brands offer is also completely hermit crab safe, and often contains extra calcium.

Instant Ocean
Instant Ocean Reef Crystals
Kent Marine
Red Sea
Seachem Marine
Tropic Marin

All of the major salt brands are measured the same, depending on how much you need:

1 gallon of water to ½ cup of salt mix

½ gallon (which is 2 quarts) of water to ¼ cup salt mix

1 Pint (which is 2 cups) of water to 1 Tablespoon (which is 3 teaspoons) salt mix

1 cup of water to ½ Tablespoon (which is 1 and ½ teaspoon) of salt mix

Storing Water

Many crabbers mix water in advance and use it as needed, and most keepers can get away with leaving the water at room temperature. However, room temperature, stagnant, dechlorinated water can grow bacteria, algae, and diatoms rather quickly. It’s recommended that if you have problems with this to refrigerate the water for safety and then allow it to warm to room temperature before using it, or mix it up fresh only as you need it.

How Often to Change the Water

For small bowls and pools: the water should be changed every two to three days, or immediately if it becomes dirty or has substrate dragged into it. Ideally, daily water changes would be the best option.

For larger pools: you might be able to get away with a few more days, however any organic material (poop, food, cocofiber) that is in the water will raise the ammonia levels rather quickly which is not good for the hermits to be drinking or bathing in.

For large pools with true filters: water testing should be done to see if the pools have cycled properly. (Please search for "Fishtank Cycling" on the internet or ask in Food & Water if you are unsure what this means.) If uncycled then the water will need to be changed out just as often as you would for an unfiltered pool. If cycled, then maintain as you would a fish tank - vacuum any debris from the bottom and change out at least 25% of the water per week, depending on what your water test results show.