By Bob Goemans
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Bob Goemans corresponds with Carlos Mateos

Carlos Mateos writes...

Dear Mr. Goemans,

I am the owner of a pet shop, and we are specialized in marine aquariums and have read with great interest your new book, 'Marine Fish Health & Feeding Handbook, which has been inspiring! In your book you indicate that the quarantine tanks should be kept a 1.010 - 1.013 Specific Gravity (SG), and the fish sale tanks at 1.017- 1.018.

A great percentage of our customers are reef keepers, and their SG is about 1.024 - 1.026. If we kept the sales tank at 1.017 - 1.018, how should our customers perform the acclimating when they take home their choices? They generally use a slow drip method. How long should it take to go from 1.018 to 1.024?

We are going to put in operation the system described in your book, as we think it's excellent!

Thank you and best regards,

Carlos Mateos


C/Arzobispo Doménech 40

50006 Zaragoza


Bob replies...

Dear Carlos,

Thanks for your email and nice words about the book. You have a very good question, as many shops normally maintain their fish-only systems at lower SG levels because it reduces the chances for parasitic infestations, provides somewhat greater dissolved oxygen content, and slightly reduces the level of salt mix they have to use to maintain the system.

Nevertheless, in the book you'll notice the recommendation not to raise SG more than .002 - .003 units per day was in the section devoted to 'Hyposalinity' treatments, where animal's are experiencing/being treated with a SG of 1.010 - 1.013 for a 'specific' reason. Not shop systems having a somewhat lower SG than home aquariums. Keep in mind there is a difference between 'Quarantine' (an area where the animal is observed for possible problems/usually maintained at near normal SG) and/or shop systems, and treatment/hospital tanks where specific problems are treated.

Therefore, when treated with the Hyposalinity method, again for a specific disease problem, the rule applies - do not raise more than what is mentioned above. But quarantine differs from a treatment for a defined malady. Animals in quarantine/local shop main systems are not subjected to such a radical drop in SG. Selling a healthy fish to a customer that maintains a SG of about 1.024 and uses the drip method for acclimating should not be a problem when shop systems are reasonably lower, such as yours. Keep in mind the SG can always be dropped, even to Hyposalinity levels immediately without any harm to fishes, but recovery from this level must proceed as mentioned above.

As to the length of time it would take to raise your shop SG level to the home aquarium that is not the major factor of interest here in my opinion but what is, is the quality and temperature of the water the animal is going into. Therefore, it's the 'Stress' factor that is really important when acclimating between shop and home aquarium. In fact, its sometimes simply best to slip the animal, especially large animals, out of the bag into the home aquarium (no water from the bag should inter the aquarium), preferably at dusk when the main lights are about to go out or after feeding those in the aquarium. And that stress factor, which includes a lot of variables, e.g., such as time between shop and home, how the animal was bagged, the size of the bag and its water content, the temperature of the aquarium water in relation to bag water, is what the aquarist needs to take into consideration as he or she monitors short drip acclimation timeframes. And it should go without saying, that any specimen showing undo stress during this acclimation should directly be placed into the main aquarium unless quarantine quarters are readily available.

Hope this helps,



Salinity; Acclimation Protocol

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