Water change and testing

[SunfishFun]

I found your article greatly informative - thank you! I do have a couple of questions about maintaining a Q tank.

First, do you have recommendations for performing water changes, either regarding quantity of changes or frequency? For the changes do you favor using water from the main tank over "new" saltwater?

Also, in addition to the nitrogen compounds and pH, do you think one needs to test any other parameters such as Alkalinity/KH or Calcium?

If I set up my tank using PVC or ceramic pots as hiding places, do I just use no substrate at all?

Lastly, does one generally need to quarantine invertebrates such as a newly purchased cleaner shrimp? Also, having a cleaner shrimp in the Q tank will not help larger new fish? In a different situation, if I hope to facilitate a goby-shrimp commensal relationship, can I place the shrimp in the Q tank (with a noncalcareous substrate for burrowing) as long as copper is not used?

Thank you again for explaining the importance of quarantining fish!

[ATJ]

Thanks for the kind words.

The important thing about the water is quality, so you will need to perform some changes to ensure the water quality is good. As fish are generally less sensitive to water quality issues and as you will tend to have a lower bioload, water changes need not be as frequent in a Q tank as in your display tank. While the tank is fishless I would not worry about water changes at all. If the Q tank has been fishless for an extended period, I'd recommend a largish (20-50%) water change just prior to adding fish. When I have fish in mine, I tend to keep the same routine as with my other tanks (10-15% every 2 weeks) but you could easily take that to once a month.

If you do regular water changes on your main display, using this water for the Q tank changes is a very good idea. This means you can do larger and more frequent water changes on the Q tank at no extra expense (other than time). The quality of the water will be more than adequate.

You don't need worry about calcium, but you may want to keep an eye on the alkalinity. As this is the buffering system of the water, if it falls your pH may not be stable. I find my alkalinity does not have to be all that high - maybe 2-2.5 meq/L - to give me stable pH.

You won't need any substrate for most fish. However, most wrasses bury at night and it would be stressful for them not to have substrate. Sand sifting gobies are in the same category to some extent and may be difficult to get feeding without some kind of substrate.

In theory, all organisms should be quarantined before placing in the main tank. However, the risk of introduction of parasites or other pathogens with invertebrates is quite low and in my opinion does not warrant another tank - an invert quarantine tank would best be a separate tank. Now, corals are a separate category of inverts again, and there are good reasons to quarantine them - but that would be a whole other article.

There'd be no reason (other than if copper had been previously used) that you couldn't put the shrimp in the Q tank with the goby as you suggest.