Is this aptasia?

Yep! Peppermint shrimp, Berghia nudibranchs are known to eat them. You can also inject it with some kalkwasser or hydrogen peroxide, and it should kill it.

If that is the only one, which is almost never the case, and if you can remove that rock or get a pair of wire cutters or tin snips to it, snip/cut/break that little portion of the rock off, most other methods will leave some form of life behind and soon more will pop up....I have had success with pepperment shrimp when added in groups of 3 to 4 as far as would they live based on your cycle I am not sure of your parameters and im not sure what you mean by a ammonia spike unless you plan on adding ammonia, what you should be looking for is a nitrite spike followed by a nitrate spike and then when you can add ammonia to 2 or 3ppm and it can be removed by your system in 24 hours (ie nitrite and ammonia are zero) your tank is completing the nitrogen cycle fast enough for fish...you will want to then focus on nitrate removal before you add coral

Edited by Bryce - January 10 2015 at 10:31am

Just my .02 here, if you're at 0 ammonia and 0 nitrite with 20 nitrate I'm going to say you missed the ammonia and nitrite spikes along the way. Water changes will export the nitrate and or some macro algae. I belive you have completed the cycle. I would ask others to weigh in on this as well. Nitrate is what happens after ammonia and is converted to nitrite and then nitrite converted to nitrate. Again just my .02 worth. Aptasia I would try and either chip a part of the rock off or something as they can take over a reef which leads to unhappy aquarist.

Haha, omg, two weeks ago ago after first getting these readings I posted (http://utahreefs.com/forum/forum_posts.asp?TID=74176&KW=20+ppm&PID=580325&title=end-of-our-cycle#580325) asking if I was correct in assuming that we had completed our cycle, and the consensus was that, without having seen diatoms (still haven't), we had not completed our cycle and the problem was a lack of bioload. So we started feeding the crap out of the tank with fish food, and there's a rotting deli shrimp in there as we speak. Still, the readings sit at 0 ammonia, 0 nitrite, and 20 nitrate.

I'm pushing for snipping the rock--we really only have seen one, and my fiance stares at that tank all day--but he's pretty stubborn and wants to go the peppermint shrimp route. We just had a little argument about it. :) He really doesn't want to snip the rock, and he's convinced from what he's read on other forums and websites that a few peppermint shrimp is the way to go. So if I let him get his way, do we need to do water changes or anything first, or just go ahead and get a few peps and see how it goes?

Also, Reefer4Ever, can you clarify for me a little what you're saying about water changes at this point? We should do one before adding new livestock, because we want to get nitrates back down to 0 as well, and get rid of macroalgae (of which we have some, but not a ton)?

I would go the injectable route with aptasia.  If you touch it you will noticed that it will completely retract into a little hole.  You need to completely cover that hole -- that chokes it out and it dies.  You can even use super glue.  Keep up with aptasia and you won't have a problem.  So far in my 90 G tank I have only found 2 aptasia.

Not all varieties of peppermint shrimp will eat aptasia.  You could end up purchasing the wrong kind -- although shrimp are fun to watch even if they don't eat what you want them to eat.

Water changes are done to export nutrients that are not needed (nitrate and phosphate). You will probably never get nitrate down to zero but a lot of in habitants like a little nitrate. Keep the macro algae growing as it use both nitrates and phosphates to thrive. I would find another ammonia test and if the reading is 0 I would safely say your cycle is complete. I'm am thinking that you are going to find out its time for a fish and I would add fish slowly to let the system get used to the new bio load.

Edited by Reefer4Ever - January 10 2015 at 11:38am

So my natural next question is going to be: What is your favorite choice for a first fish to add to a newly cycled tank? What's the best in terms of being hardy/a good tank-breaker-inner/relatively easy for first-time aquarists?

This is a better question, what does your fish list have on it as that would make it easier to know what to add. I am very curious with the water tests at the lfs. I have never had much luck with strips and matching the color is just a best guess. They can give you some info in a pinch but I would look into get a reef kit, salifert, red sea something along those lines and opinions vary drastically. I shall be awaiting post from water test at lfs

Edited by Reefer4Ever - January 10 2015 at 12:02pm

Badfinger, it's VERY tiny, probably just a few centimeters. I'm terrible at estimating length, but it can't be more than a quarter-inch.

How do these other test kits work (API, etc.)? Not color-based? Because I hate trying to read those color strips. My fiance is good at distinguishing colors, but I'm TERRIBLE at it. I once wore a brown belt for years before finding out it was actually black. :)

Once you're done with the cycle you will rarely if ever test for ammonia and nitrite again as I don't test either of those at all now. Don't go crazy spending much money on tests for ammonia and nitrite as you will be moving in the direction of testing other parameters (calc, alk, mag, phosphates, nitrates).