HCA: Hermit Crab Association

So my boyfriend has a saltwater setup and was wondering what his protein skimmer was pulling out. I, intrepid Internet delver, went out to find out. My initial reaction to one of my findings was to have a small fit.

Now, mind you, it's only one study and I know that having only a single source isn't really a great way to go about things, but here:

http://www.reefkeeping.com/issues/2002- ... /index.php

For this who don't want to go all the way through this page: There are much higher levels of toxic metals and trace elements in artificial salt mixes than in the ocean.

Now, regarding this, many aquariums keep their denizens for many years without ill effect, and some have managed to even successfully breed things like shrimps (which wouldn't be possible if the juveniles were sensitive enough to die in the presence of these trace elements). However, there is a pretty good point in the study: Most of the creatures that die of "shock" from improper acclimation should not be dying from a difference in salinity - the theory being that the difference in trace elements is too much to take all at once.

What does this mean for our hermies? Probably not much, but for some of the older crabs who just up and die, it may be worth considering toxic buildup in body tissues. Thing is, I really don't see any alternatives to this unless you live in a very clean beach area, in which you should probably get your saltwater from the ocean. Other oceanfront areas are very likely just as bad in pollution and such as artificial saltwater mixes are in toxic elements.

If anything, it's more reason to give them foods that aren't soaked in preservatives and away from aerosols and such. Saltwater is a constant in crabbing, and if we know that that constant may have toxins and detrimental things, then for the sake of our crabs we should keep other toxic elements as low as possible.

I was uncomfortable using an artificially created sea salt. Something just didn't sit right with me in using it. I use Red Sea, which is a natural salt. It's salt that's been extracted from the Red Sea in Israel. All natural.

That's not true about the Red Sea salt mix - it is a mixed formula, though most of the ingredients are natural. Notice they say "excessive heavy metals", which means they are still present.

The end result is pure, white, food-grade crystals of Sodium Chloride that also include 45 of the other elements that are naturally present in the waters of the Red Sea. This element enriched sodium chloride is the basis for both of Red Sea’s salt mixes providing part of the “living reef” inside every grain of harvested salt.

This sodium chloride with its natural array of minor and trace elements, that is free from excessive levels of heavy metals or organics, comprises over 72% of Red Sea’s salts and therefore by definition provides a quality and homogeneity of finished product that is unachievable artificially.

The next stage in the process is to add back to the sodium chloride the calcium, magnesium, potassium and all of the other elements in a consistent, homogenous mix. This is achieved by working in small batches with strict quality control.

The absence of excessive levels of heavy metals in our materials obviates the need for chemical binders that significantly affect the function of protein skimmers

http://www.redseafish.com/uploadimages/ ... %20Eng.pdf



There are excellent charts on About.com since NONE of the salt mixes are perfect in any way.

This gives the natural composition of sea water. However, composition does vary across the globe, and this chart gives a rough average:

http://saltaquarium.about.com/od/planas ... water-.htm


This chart lists how different elements in marine mixes compare to natural sea water, showing if they are the same as, higher, or lower:

http://saltaquarium.about.com/od/planas ... ary-El.htm

As you can see, Red Sea is considered to be extemely high in Boron as compared to natural sea water. Even so, it's still considered one of the best for saltwater tanks.


I think the question of which is the safest salt to use comes down to what is the most harmful for the specific species your keeping. Salt-water fish will be more tolerant of some elements than others, as will corals, and hermit crabs are in a separate class all together. What works best for one type of species probably isn't as good of a choice for another.

My question would be what are hermits most sensitive to and therefore shouldn't be exposed to over great periods of time? (And conversely, what do they need more of so they aren't lacking something important!)

My question would be what are hermits most sensitive to and therefore shouldn't be exposed to over great periods of time? (And conversely, what do they need more of so they aren't lacking something important!)

Unfortunately I doubt much research has been done in this area. Its also possible that what clypeatus need and are sensitive to could be completely different than what compressus need and are sensitive to.