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You are browsing the archive for salt.

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by Stacy

The importance of the right kind of salt

February 21, 2013 in General

written by Jennifer Nielsen

The existence of an ocean water dish is a source of great controversy in the world of hermit crab owners. Why the importance of this type of water is rarely debated, it seems that the products used in the creation of Ocean Water are the source of much debate. Just as all hermit crab owners know not to use table salt for their crabs, there are two types of salt available for aquarium use. Fresh Saltwater as well as Ocean Water Salt, which although made of the same components have vastly different role within the world of fish keeping.

A saltwater dish is offered as a means for hermit crabs in captivity to gain access to the ocean with in the habitat. In the wild, a hermit crab would normally crawl down to the sea side to get sea water to help balance the ph/ion levels within their shells. However, in the man-created environment within the habitat, this cannot happen unless a human is providing this type of water. The product used to create this water is of critical importance for this reason, plus in case of injury, salt water is also naturally defecting that will assist in healing of wounds. Hermit Crabs have been known to be seen soaking an injured claw within the salt water pond. Also, molts tend to go a better in the habitats where salt water is readily available.

In order to understand the difference in the product lines, we need to see what Natural Sea Water (NSW) is composed of. The first ingredient is salt of course. However, it also contains about 70 other trace chemicals within it. So while the primary ingredient is in fact common salt (NaCl) there is also several other elements which are key to the composition of Ocean Water. The major components in addition to Chlorine and Sodium are Magnesium, Sulfur/Sulphur, Calcium, and Potassium. Also, common minor components are Bicarbonate, Bromine, Strontium and Silicon. These are considered to be essential to the creation of artificial salt water. This is in addition to other elements, which are in lower amount but found in NSW, such as Chromium, Cobalt, Copper, Fluorine/Fluoride, Iodine/Iodide, Iron, Manganese, Molybdenum, Nickel, Phosphorus/Phosphate, Selenium, Tin, Vanadium and Zinc. Also it is important to note that in the creation of artificial ocean water mixes also tend to be over in Nitrogen/Hydrogen, Nitrate-Nitrogen, Phosphorus as well as Silcon. So offering just one of these elements, such as just the salt, is not truly providing a Salt Water, for several ingredients are missing from the equation.

Now, this is not to say that the salinity level found around the world is stable. Factors such as weather, heat, and location are also factors in the composition of salt water. The Dead Sea is in fact the saltiest body of water in the world. Water located around the equator is also saltier than that which is found in the artic. While this could be important to different varieties of Hermit Crabs, that is a subject for more research to find out which products mimic different water conditions world wide.

Freshwater Salt is designed to primarily be a treatment of illness in fish. Specifically, freshwater fish can tolerate low slowly introduced salt in their water. Natural Freshwater does contain salt, but compared to the amounts found in NSW water, the volume of this is significantly lower. Products designed with only this purpose in mind, tend to lack the other elements found in Sea Water. The same is true for cooking salt made from evaporated ocean water. For while the salt is sea salt, it is lacking the other components that make ocean water what it is.

Ocean Water salts, however, provide not only the salt needed but the other components as well. In fact, the label Ocean Water mixes might be a better term for these products because of the fact that they are not just containing one part of the water, but a variety of components that are found in NSW. For the Aquarist who keeps salt water tanks, this is of critical importance to their pets. Therefore, they tend to go with mixes that are more than just salt. In trying to offer Hermit Crabs ocean ponds, it is important that a mix with true composition closest to NSW is used which is why ocean water salt is preferred over Freshwater Salt.

Websites used to provide information in this article are:

Gore on Salinity

Dead Link-Page not Found See archive of webpage here.

Sea Salt mixes

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by Stacy

FAQ A Close Look At Salt Products

October 16, 2012 in FAQ, Food and Nutrition

Hermit crab enthusiast Jennifer Nielsen compares several brands of sea salt mix in this article.

Written by Jennifer Nielsen (aka redjln)

While many hermit crab owners realize the importance of providing Ocean Water to their pets, there is a question over which type and which specific product is the best. To answer this, I got Instant Ocean and Reef Crystals enriched blend by Aquarium Systems, Doc Wellfish’s Aquarium Salt, and Aquarium Salt by Jungle. I have gotten a container of Distilled Water to test the products in.

Now, I will disclaim right now that I do not have access to a laboratory of equipment. All I have to test with is a test kit by the name of Marine Master Saltwater test kit. This test kit was not the most expensive, not the cheapest. The test kit can test for pH, Nitrite, Ammonia, and Nitrate. Nitrate/Nitrite is both forms of Nitrogen that is on its way to be coming ammonia. Too much of both of these are deadly to both humans and animals, but are the final stages of the breakdown of waste products from living things. This is a critical part of marine fish keeping, and which is why it was included in the test kit. However for the sake of Hermit Crabs which consume the water, and the fact that nothing is living in this water, testing for pH is the only test that is logical.

What pH is defined as is a measurement of the concentration of hydrogen and hydroxide ions, as well as measures how acidic or alkaline it is. The scale ranges from zero to fourteen. Seven is the ideal number for that is neutral. Less than seven is an acidic solution, and greater than seven is alkaline solution. A good ocean water mix should have between 8.0 and 8.3 pH as that is what the ocean’s pH is. For the sake of this test, I am using this as means to discover if anything else is present in any of the waters.

I also got an inexpensive hydrometer for this testing. What a hydrometer is a means of measuring the amount of salt in water. Natural Sea Water is about 3.5%, yet this is affected by a variety of factors including water temperature. According to my research, marine tank owners tend to want their salinity to be between 1.021-1.024 and since the marine tank owners animals live in imitation ocean water I defer to the range that believe to be best. It has to be tested within a container that allows for the meter to float, which with it being a rather long glass tube posed it own challenges. Eventually I found containers that would work and they were boiled to sterilize them.

For a truly fair test, I decide to use distilled water. Distilled water is water that has no additives in it. Unlike tap or well water which will have minerals or other items in it which I figured could effect the results, I decided to go with as pure of water that I could find.

The first thing about The Doc Wellfish and Jungle products is terms such as “General Tonic and Stress reducers” or “Tropical Fish Treatment or with a remedy” on the packages. The Jungle product even gives a nice set of instructions on how to use this product to clean the tank. Neither the Jungle nor Doc Wellfish products truly give a method of creating ocean water. Which is what the hermit crabs are in of needed. Now the Instant Ocean product just explains that it comes close to being a natural ocean environment. Crystal Reefs also makes the same claims, but that their product also has added calcium.

The looks of the products vary. Doc Wellfish salt is shaped like large crystals. The Jungle Product has smaller crystal. However the Crystal Reef product has tiny crystals and Instant Ocean is a powder. From the standpoint of having to dissolve these products, Instant Ocean would appear to be the easiest to do so with. However, it turns out that all the salts were quickly and easily dissolved, Doc Wellfish only requiring a bit more stirring than the other products in the distilled water.

Now, both Instant Ocean and Reef Crystals give the instructions of a half cup to a gallon of water. There are sixteen cups in a gallon. There sixteen tablespoons in a cup, which meaning eight tablespoons in a half cup. Also there is a ratio of three teaspoons per tablespoon. Now to make a cup of ocean water with these products, I worked out that sixteen cups of water divided by twenty four teaspoons equals about one and half teaspoons. For a cup of water, I would need to use one and a half teaspoons. Now for the Jungle Salt and Doc Wellfish, I figured out that the directions of one tablespoon per five gallons worked out to about less than one-tenth of a teaspoon per cup. Plus, the ratios seemed a bit small, that I was not sure my hydrometer would be able to trace it. So I decided that one quarter of a teaspoon to four cups of water would have to work.

Then containers with the mixtures would also be given a chance to sit overnight to give the salt time to mend with the water and measurements taken. Although the packages claimed that the water would to be pretty much ready to use right away. My research suggested that allowing the water to rest prior to use. Also considering the amounts that most hermit crab owners use, any effects of the ocean water sitting would have an effect. This would show what the levels as if they water had been sitting for a bit. I know that with my thirteen hermit crabs it takes about a week to go through one cup of water.

The first test results were interesting taken after about an hour from the time the water was created. Instant Ocean landed in the center of the 1.020 to 1.030 range. Crystal Reef measured 1.034 to 1.036 ranges. This is higher than the preferred range for salt. Jungle’s salt, in spite of the ratio being higher than what the packaged suggested turned out to be ranking very low salt content of 1.000. Which when I tested my drinking water, is the same amount of this. Doc Wellfish tested to be 1.002. The next day, the hydrometer show no results when I tested the Jungle water. However, the Instant Ocean and Crystal Reef stayed the same with regards to the results I had gotten the day before. I waited a few more days and tried again. The result with Crystal Reef had changed, for the salt level had stabilized within the proper range after four days.

The pH test worked my changing the Ocean Water color. Instant Ocean and Crystal Reef measured a pH of 8.0 after creation and remained stable at this for the next few days. I could not get a reading for the Fresh Water Salt products. They had less than 7.8 pH content in it. The pH for Doc WellFish continued to decrease as well as for the Jungle Product, as I could tell by the color, but was not able to measure with my kit.

I would say the besides the fact the Ocean Water Mixes designed for Marine Tanks do contain more items in it than the products designed for Freshwater tanks. That the fresh water products would require a lot more salt than their packages suggest to create ocean water and are also missing the “something” that cause the pH in the marine products to stabilize. The Jungle Salt even breaks down to not even being in measurable in the water. The fact that Instant Ocean was within range for everything from the start it might be the preferred product to use. Yet, Crystal Reefs could be modified with the addition of some more fresh water to fall within the proper range. However, after sitting four days, it came into range on its own. If I had added the water would have made it back out of range for being too low in salinity.

The main conclusion I came to was that there is something different about the products that are used/designed for Marine Tanks. Something is present in the water that makes the pH stay stable and not decrease. For this reason alone, I advise that people use a Marine Salt mixture, and since most people may not have access to a hydrometer, mix the mixture light so as not to burn the hermit’s gills with too salty of water, considering that tap water also might contain a trace of salt in it.

For further information regarding freshwater salt mixes vs. ocean/sea water mixes that has been recently discovered, please see the end of Ocean Mixes at:
How do I mix ocean water

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by Stacy

FAQ How do I mix ocean water?

October 16, 2012 in FAQ

Special credit thanks to Wendy at Hermit Crabs R Us for compiling and sharing this list!!

After mixing all ocean/sea mixes leave sit for at least 12-24 hours prior to offering to ensure that all the crystals have dissolved.

Crystal Sea Marine mix Bioassy Formula
The site from which I purchased this mix indicates 1/4 lb or 1/3 cup will yield 1 gallon. I found it to only be 1.016 SG when mixed this way. I tested it using 2 different hydrometers-one that was also purchased at the same site as the salt mix. I mixed it using 1/2 cup and got 1.021. (I add an additional tablespoon for my C. Perlatus to raise it 1.023)
* 1 1/2 tsp per 8 oz (1 cup) water
* 1 TBSP per 16 oz (1 pint)
* 2 TBSP per 32 oz (1 quart)
* 4 TBSP per 64 oz (1/2 gallon)
* 8 TBSP per 128 oz (1 gallon)

Instant Ocean
The package indicates to use 1/2 cup (which=8 TBSP) per gallon.
* 1 1/2 tsp per 8 oz (1 cup) water
* 1 TBSP per 16 oz (1 pint)
* 2 TBSP per 32 oz (1 quart)
* 4 TBSP per 64 oz (1/2 gallon)
* 8 TBSP per 128 oz (1 gallon)

Oceanic Natural Sea Salt Mix
The package to make 5 gallons indicates .29 lbs/gallon. I measured the package and it was approximately 2 1/2 cups. Which is 1/2 cup per gallon or 8 TBSP
* 1 1/2 tsp per 8 oz (1 cup) water
* 1 TBSP per 16 oz (1 pint)
* 2 TBSP per 32 oz (1 quart)
* 4 TBSP per 64 oz (1/2 gallon)
* 8 TBSP per 128 oz (1 gallon)

* This is the salt I am currently using and 8 TBSP makes a specific gravity of 1.021. I use an additional tablespoon to raise the specific gravity for my C. Perlatus. I also provide Doc Wellfish crystals in the food dish as well.

Red Sea Salt
The package directions indicate 2.8 lbs. dissolved in 10 US gallons, which is .28 lbs for 1 lb which again is basically the same as Oceanic 1/2 cup per gallon (or 8 TBSP)
* 1 1/2 tsp per 8 oz (1 cup) water
* 1 TBSP per 16 oz (1 pint)
* 2 TBSP per 32 oz (1 quart)
* 4 TBSP per 64 oz (1/2 gallon)
* 8 TBSP per 128 oz (1 gallon)

Tropic Marin Sea Salt
The package instructions indicate 151 grams = 1 gallon. 151gms x .0353 = 5.33 ounces.
5.33oz/8(oz in a cup) = .66 or 2/3 cup per gallon. There are 31.68 or 32 tsp in 2/3 of a cup.
* 2 tsp per 8 oz (1 cup) water
* 4 tsp ( 1TBSP+1tsp) per 16 oz (1 pint)
* 8 tsp ( 2TBSP+2tsp) per 32 oz (1 quart)
* 16 tsp ( 5TBSP+1tsp) per 64 oz (1/2 gallon)
* 32 tsp (10TBSP+2tsp) per 128 oz (1 gallon)

So basically all of the dry salt mixes tend to be 1/2 cup or 8 TBSP per gallon of water. If you are unsure if your sea water is salty enough or too salty you can purchase a hydrometer which measures specific gravity. The specific gravity of sea water varies depending on location, but is generally somewhere between 1.020 and 1.025. To get an accurate result with your hygrometer, the water should be around 77 degrees Fahrenheit.
If you are offering both a de-chlorinated fresh water dish as well as a de-chlorinated salt water dish, you needn’t worry if the mix is too salty. The crabs can adjust their shell water accordingly. If you have C. Perlatus, saltier water is more beneficial as their shell water has been shown to be much higher in salt content than those of other species.
In addition, if the salt water dish is not salty enough, they will need to obtain natural sea salt from other sources such as their diet. One option is to provide a small pile of the Sea salt crystals with their food.
Here is some additional reading about specific gravity (versus salinity)

Saltwater Salinity and Specific Gravity


* CUP tsp TBSP
* ¼————–12——–4
* ½————–24——–8
* 1————–48——–16
* 2————–96——–32

* How many ounces in a:
* 8 cup
* 16 pint
* 32 quart
* 64 1/2 gallon
* 128 Gallon

Conversion Table

Additional information added to Wendy’s compiled Ocean mix, by Marie (aka ladybug15057)

Both the ZooMed Part 2 and HBH hermit crab salt mixes were tested for salinity levels. If mixed per the products instructions, they do not register a salinity level on a hydrometer. Land hermit crabs should be offered an ocean/sea water pond with a salinity level of 1.021-1.024.
ZooMed Part 2 has a yellow dye within it, something a hermit crab does not need within their diet. Within this product, it does not contain an ingredient to remove heavy metals from tap water, as well as ZooMed Part 1 fresh water conditioner does not contain a heavy metal neutralizer.
HBH Hermit crab sea salt Ingredients: sodium chloride, magnesium chloride, calcium chloride, potassium chloride, potassium iodide
It contains the wrong form of calcium and it contains normal table salt ingredients sodium chloride/ potassium iodide. HBH salt mix also contains a highly corrosive magnesium chloride that is used to stabilize the iodine. (Thanks to SUE, RFCrabs for this information regarding HBH salt mix)
It is not known for fact whether either of these Salt mixes for hermit crabs are made with freshwater salt mix or ocean/sea water mix. This includes the Glub Salt water sold for hermit crabs.
Ocean/sea water elements are different than those of freshwater. Hermit crabs need the elements that are found in ocean/sea water to remain healthy:

Advanced Aquarist Salt Mixes Part 1

Advance Aquarist Salt Mixes Part 2

Salinity GPC EDU

Saltwater Salinity and Specific Gravity Algone

Why is the Ocean Salty Palomar EDU

Sea Salt Mixes- About.com

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by Stacy

FAQ Salt Water

September 27, 2012 in FAQ

I hear a lot of discussion about salt and fresh water.

How do I safely get my salty water salty?

How necessecary is salty water to hermit crabs?

Also, I was hoping to get a sloping, deep reptile dish with good traction to let the hermit crabs bathe themselves instead of me misting them or taking them out of their cage to be bathed. Should that dish have salt or fresh water?

Salt water
Originally written by CrabbyJo

To get your salt water salty, the safest way is with an ocean salt mix you can purchase at your pet store. NEVER use table salt meant for humans. There are anticaking agents in them that can be dangerous for your crabs.

Pet stores may have some salt water mix for hermit crabs, do not purchase these salt waters or mixes. Use the salt used to make ocean salt water specifically for salt water fish tanks. There are a few brands you can choose from.

It is VERY important that you get a water dechlorinator, preferably one that removes chloramine, chlorine, and heavy metals if you are using tap water. If your water is fluoridated, it is highly recommended you use distilled water as there currently is no way to remove fluoride from water, and fluoride can be deadly to your hermit crabs.

If you do use distilled water, you will need the properly mixed ocean/sea mix to replace what the distilled water is lacking. Distilled water does not need a dechlorinator to be used as it has no elements or minerals within it.

As for hermit crabs needing saltwater, it’s very important. These crabs live near the ocean, and can adjust the salinity of their body themselves if they have the proper access to both fresh dechlorinated and ocean salt water. Ecquadorians and perlatus are more sensitive and need it more than clypeatus. Often you will see your crab, pre molt, sitting in the salt water dish filling his shell with water. He needs it to help him have a successful molt, as well as for his general all over health.

As for the bathing, I have a deep dish myself full of fresh dechlorinated water so my crabs can bathe themselves, and a slightly shallower salt water bowl so they can dip their shells in if they want to, although it’s not deep enough for them to “swim” in. Bathing practice of hermies is now in question except for in cases of a “need to” situation (such as reintroducing an isolated molter to the main tank, or possible mites or fungus), and many crabbers are forgoing this practice and allowing their hermies to bathe themselves in a large dish as you describe.

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by Stacy

Why is an ocean pond needed?

September 25, 2012 in Caresheets

Originally written by Vanessa Pike-Russell-Updated by Stacy Griffith

All hermit crabs require some access to salt in their diet, no matter what species. The habitat of land hermit crab species differs from location to location, and they have adapted to the environment they live in.

A brackish (between fresh and sea water) solution is recommended for the “Ocean Water” pool within your tank. If you are using distilled or spring water it may have varying amounts of salt already within the water, so take that into consideration.. It is important to note which type of water you use.Varying habitats of land hermit crab species. It may surprise you to know that the habitat of land hermit crabs is rather diverse. Some live in rainforest areas while others exist on coral atolls or inland areas. If you have many species
within the same crabitat then you will notice that some will drink more sea or ocean water than others. It is important that you provide an ocean or sea salt water pond within your crabitat so that each crab can take what it needs and lead a happy and healthy life.

“Although there are relatively few species of Coenobita, individuals are numerous in tropical and subtropical maritime regions particularly supralittoral areas and small islands, although some penetrate further inland. Certain species are restricted to beaches (e.g. C. perlatus (H. Milne Edwards, 1837), C. scaevola (Forskal 1775), C. spinosus (H. Milne Edwards, 1837), C. cavipes (Stimpson, 1838) while several other species may penetrate long distances inland, e.g. C. clypeatus (Herbst, 1791) on Curacao, C. rubescens (Greeff) and C. brevimanus (Dana, 1852) in rainforest, C. compressus (H. Milne Edwards) (de Wilde; 1973; Burggren and McMahon, 1988). Coenobita rugosus (H. Milne Edwards, 1837) may live on the beach or penetrate inland in situations where fresh water is available (Yamaguchi, 1938; Vannini, 1976). stages.” Greenaway (2003 p. 13)

Beach-dwelling Land Hermit Crabs Some hermit crabs live on or close to beaches and would have access to seawater and a diet high in salt. In captivity they will need access to sea water. You will often find hermit crabs which have been denied sea salt water solutions spending a lot of time in the ocean water dish once you get them home. Within the United States C. perlatus and C. cavipes are available in some pet stores and mall carts. According to Peter Greenaway, these species are beach-dwelling land hermit crabs and would require access to sea water to survive.

“Certain species are restricted to beaches (e.g. C. perlatus (H. Milne Edwards, 1837), C. scaevola (Forskal 1775), C. spinosus (H. Milne Edwards, 1837), C. cavipes (Stimpson, 1838)… Beach-dwelling coenobitids drink seawater or extract it from damp sand and often immerse themselves to flush the shell.. ” Greenaway (2003 p. 13-16

Other land hermit crabs despite living away from beach areas most hermit crabs will drink the sea water from time to time or access salt through their diet. You may find your Carribean (Purple Pincer aka C. clypeatus) hermit crabs drinking the sea water. While they may not have ready access to seawater in the wild they do drink it while in captivity, and there is often a link between excessive drinking of sea water and an impending moult.

“Coenobita spp. that live away from the beach do not usually have access to seawater and indeed these species prefer dilute water unless they are depleted of salt (de Wilde, 1973). ” Greenaway (2003 p. 16)

How to create ‘Ocean Water’ from Synthetic Sea Salt

If the package doesn’t give mixing directions you will be safe using this ratio: Mix eight tablespoons (1/2 cup) of Marine Salt to a Gallon (4 Litres) of dechlorinated water. This equates to roughly 2 tablespoon per Quart/Litre.

This solution can keep for up to a week. Once mixed, the solutions should be permitted to sit for 12-24 hours prior to serving to ensure the ocean crystals have dissolved. Make sure that you shake the solution if it has been left to stand thus to dissolve any undissolved salt crystals.

Philippe de Vosjoli recommends 5 tablespoons of synthetic sea salt (such as Instant Ocean) per Gallon of dechlorinated water.

Quality brands which may be used include Instant Ocean, CoralSea, Oceanic, Reef Crystals from Aquarium Systems, and Tropic Marin. Each brand should be mixed according to the instructions on the package.

For further information, and smaller quantity mixing directions, please see the Ocean Mixes page.

Instant Ocean

From the Aquarium Systems website:”Instant Ocean synthetic sea salt contains every necessary major, minor, and trace element and has no nitrates and no phosphates. It was developed through sophisticated biological and chemical testing, and every batch is analyzed to assure consistent high quality. Exceptional solubility, uniform particle size, and outstanding package value have made Instant Ocean salt the choice of aquarists for over 30 years. No other product outperforms Instant Ocean salt. Our guarantee of quality is supported by a history of proven usage. Instant Ocean is the world’s most popular brand of synthetic sea salt.” Add 1 1/4 tablespoons of Instant Ocean to a Litre of dechlorinated water  

Tropic Marin

“Tropic Marin sea salt is manufactured from pharmaceutically pure salts and is based upon the most recent scientific analysis of the tropical oceans. It is free from synthetic additives and contains no nitrates, phosphates or silicates. Tropic Marin Sea Salt turns fresh water into salt water, which is practically indistinguishable from natural seawater.”Add 151 grams or four heaped teaspoons of Tropic Marin sea salt for 1 gallon of de-chlorinated water.



Greenaway, P. (2003)Terrestrial adaptations in the Anomura (Crustacea: Decapoda).
Memoirs of Museum Victoria 60(1): 13-26 (2003).

Aquarium Systems:: Salts


Tropic Marin


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