Help me keep a nem

[Jekyl]

So my tank is at about the 6 month mark. I check parameters weekly and the only thing out of sorts is my alk is a little high. I think around 9 or 10 which I am checking into options to bring it in range. Temp hovers between 77 and 78 salinity just under 35ppm. I have a 90 gallon. I have tried 2 nems so far. 1 BTA that thrived for a week and then hid in the rocks for 2 weeks before I had to remove it. Recently tried a LTA that I think was just a bad purchase. It only recently came to my LFS and wasn't attached to anything when I bought it. That one only made it a week. For both of them I was using black box lighting and since then have upgraded to 2 kessil a360we. A RBTA is my #1 thing I would like to have but I'm not willing to keep taking chances. So I defer to the experts on here. Could my lighting have been the issue? I cant see anywhere in my water parameters that could have been the issue. Any other things I can look into? Basically any advice would be greatly appreciated. I'd love to drop the money on a large black widow nem but foremost I don't want anything else to suffer from my wants.

 

[OnyxPerc]

You've come to the right place for help and advice mate, props to you for that.

Most people on here will tell you that your tank needs to mature, that 6 months is too young and the tank should be at least a year old before attempting to keep a nem. I've kept nems in tanks that are only weeks old with great success though. The most important thing is stability. They do not tolerate swings in parameters well (temp, salinity, etc.).

If you do not already have one, an ATO is your best friend to keep salinity in check. Also, I'm assuming you're relying on a probe since you gave us conductivity, so make sure it is calibrated. It's not a bad idea to double check it every once in a while with a refractometer. I calibrate ALL my probes once a month and check values with other instruments/test kits to be sure they are accurate.

If your parameters are good and you can keep them stable, then your next step is to make sure that you are getting a specimen that will have the greatest chance of survival. You want to make sure the tentacles and the foot are sticky to the touch. The mouth should be tightly closed and it should not be expelling anything. If you're looking for a BTA, then it should not look translucent / opaque, that is a sign of bleaching / lack of zooxanthellae.

Purchasing an established nem from a fellow reefer is usually a better option than buying from an LFS. A nem from an LFS will be stressed from transport, being handled frequently, etc. Buying from a fellow reefer that has kept the nem for several months/years means much less stress and a much more hardy specimen. Luckily there is no shortage of black widows that you can get from other reefers!

Another important note is that if you're buying from an LFS then you should definitely quarantine the nem. You could observe it for 2 weeks and treat if it is sick. Some people say to treat with cipro no matter what, others say you should observe and only treat with cipro if you observe the nem is sick. I dont think there are many (or any) downsides to cipro though.