Undoubtedly, you have made the classic error of abruptly changing the light conditions. Meyers are very sensitive to significant light changes, and will drop most or all of its leaves to replace them with new leaves better suited to the new light. The blooms are in response to the stress of the tree... (it thinks it is dying) to produce seeds; lots of plants will do that. On what planet do you live that you cannot get citrus fertilizer, even by internet? Leave the blooms, but if they set fruit, BB size, then take off all the fruit, treat them properly, and your trees will recover. In Spring move them from inside to full shade; after 2 weeks move to part shade; and 2 weeks more to full sun. Reverse this in the Fall and you should avoid the heartbreaking leaf drop that Meyer container growers suffer too often

Thank you, johnmerr. Perhaps a better to have worded my question would have been, what brand of citrus fertilizer is best, and where do the readers here order it from? Usually, forum readers know who has the best price & shipping charges.

I don't grow citrus in pots, so I haven't had to troubleshoot an associated problem. That said, since your post is about to fall off the top rung, I figured it makes sense to offer my 2 cents.

It's almost always more than just one thing that isn't right when problems start happening. Frankly, it's hard to say for certain what is happening without knowing the size of the pots, makeup of the soil, etc. The best citrus resource around is Four Winds Growers. They put their money where their mouth is because their retail sales and risk of potential returns depend on it. I've followed their advice for the most part with my in ground citrus.

The answer I offer to you is to align yourself with the Four Winds Growers recommendations:
Growing Citrus in Containers. As for fertilizer, I recommend the Miracle-Gro Azalea-Camellia-Rhododendron Food (previously known as Miracid).