Broken rocks in the bottom of a pot do not assist drainage. They move the level of the perched water table up in the pot and reduce the overall volume of plant-usable soil.

What does "cactus mix" mean? Was it a pre-bagged product? Do you know the breakdown? Did you recently repot it into that mix?

The easiest way to solve the over/under watering problem is to use the gritty mix. There are some minor complications with the mix for trees indoors (ie: you need a way to deal with the runoff) - but they are easily overcome (ask me if you go that route, I have an easy/cheap solution). You will never have to worry about over-watering again with that mix.

All that said: it's possible that your tree was just adapted to outdoor growing when you purchased it - that it was used to much higher light levels and different humidity conditions. It's possible that it is just shedding leaves that are ill suited for the current environment. You say you have 2 others but have you had them longer? Are they already adapted?

It's also very likely that your soil is supporting a perched water table and that some of the roots are drowning as a result. Combined with the rocks that you seem to have added to the pot you've probably significantly reduced the volume of soil that is usable for the roots.

If you tilt the pot 45 degrees does any water come out?

Some minor leaf curl is normal on clementines.

The mix was a scots mix purchased from lowes and is the same mix that the other citrus is in. I posted the analysis of the bag at the link. I brought the other three inside the same weekend I potted the clementine. The other trees were potted earlier this summer. The clementine was recently purchased via mail order north carolina. Any tips on this one would be appreciated.

Here is a link that might be useful: Mix analysis

Al has given you some very useful tips for success.

Get rid of the gravel at the bottom of the pot. That should be your primary concern.
The gravel is going to ensure that the already inappropriate soil choice will be unworkable.

First, the late-season re-potting probably has a lot to do with the different reaction
between the previous citrus and the current Clementine.

But let's jump right to soil choice. Potting soils that contain high amounts of peat moss,
sand, and unknown "forest products," are inappropriate for citrus (and most other plants, too).
The company packaged that product to make lots of money...not to keep your plants healthy.

Josh

Since it's happened twice now maybe I should point out that my name isn't Al...

Whoops, that's my mistake! ;-0
I've thought your name was 'Al' for half a year or more....
and believe me, this ain't only the second time!
I must have referred to you as 'Al' at least a dozen times.
Good to know, though, since we already have a couple other Als.

Josh

Following some of redshirtcat's previous posts, I want to start moving the plants into the 511 mix. In order to do so, do I need to barefoot the plants. Since I have never taken a plant to barroot status, I am a bit nervous about it and would appreciate any advice or tips on it. I have read that a lot of people injure the root systems very easily.

Z6 in December... it might be too late to try to bare root the plant this year. You'd need a warmer milder day to try.

But yes: the idea would be to get as much of the soil off the roots as possible. I find that the best way to do this is to get a very large pot or bucket with no drain holes and fill it with water. Pull the tree out of its old pot and use a hose-end sprayer to break up any hard clumps of soil. Dip the roots into the bucket of water and swish it around and repeat. You want to be as gentle as possible because if you go overboard with the sprayer or a soil rake or etc you will remove too many roots.

You want to make sure the final pot and pre-moistened soil are ready to go. You will want a chopstick or a skewer to move the new soil into the cavities in the roots. I'd also use a rubber mallet and pound the outside of the pot to make sure the soil is moving into all of the cavities. You don't want any empty space. This can take awhile so be diligent. If you do get a warmer day and try this make sure the roots don't dry out - keep them out of direct sun if possible and if not make sure to mist them periodically.

Why the 5-1-1 instead of the gritty mix?

The plants are relatively small at the moment and I hope to repot them into larger pots in the future. Currently weight is a bit of a concern because they will have to be moved for an upcoming renovation. Also, your trees in the 511 looked to be doing very well.

I do not think we will have a warm day anytime in to attempt to bare root them. I have tested the soil this evening and it is currently not wet. Would my correct next course of action be:

1. Remove the rocks from the existing pot
2. Water the plant at reduced levels
3. Use some of the 511 mix to fill the void left by the rocks to improve drainage

Thank you for all of your assistance. If it does reach the 70's I will go ahead and bear root the plant.