You should be fine. When you put it in your tank, just throw a peppermint shrimp or 2 into your tank if you are still concerned. Also, you have to remember, there is very little chance of it having spread. You only had it in your tank for a couple of hours.
When we set up our 1st tank we had gotten other rock from a local fish store, we had a few aptasia on it. We never had it spread at all over a span of a month and a half. (and since we had very few tank inhabitants we actually fed these aptasia because out kids thought they were anemones and they were cool) So, try not to make yourself nuts over this. You have probably already gotten it under control with the lemon juice.
Here is a portion of a responce to a person who had aptasia in there refugium....
I know the cases are not identical. But, it gives you a so called "experts" 2 cents on the control of aptasia.
You can also search wetwebmedia.com (
Bob Fenner's site) if you are nervous about it.
"who knows if there aren't some small ones lurking in your live rock from when you bought it that you never saw. Personally, I think it is as futile to hope to keep Aiptasia completely out of a tank as it is for Michael Jackson to avoid getting colds by wearing a surgical mask (most cold viruses actually enter the body via the eyes.) Yes, you should do your best to avoid it, but without panic and paranoia. Keep an eye out and kill what you can get at if you see any. Keep nutrients under control. Like hair algae, Aiptasia only thrive in tanks with excess nutrients. If you have no shrimp eaters in your tank, you could consider adding a Peppermint shrimp. It would probably find and eat smaller Aiptasia before it can become a problem. If there's no Aiptasia, it will find other things to eat"
Good luck, Dawn