I would check again for spidermites, they always come back! If when you first got it it was very dry, it is unlikely to make it loose its leaves quickly,most times you can dry them out to dust for a week or so and they still keep all there leaves, If now you have been keeping it damp that is more likely to cause leaf loss than being dry Dropping of leaves is normaly due to the compost being too cold, or root damage / incorrect air temperature / too low humidity / lack of air due to wet compost or to an insect on the leaves . When the compost is too dry the leaves normaly fold or curl slightly more than fall off if you had spider mites they were probably why the leaves dropped, even though you couldnt see them as there were not enough to see, they probably were still there After repotting as aesir32 says, your not supposed to fertilise them for a short time, but i do and have had no problems, with the fertiliser you are best getting a citrus fertiliser as unlike a lot of plants they realy like the correct levels, especialy of micronutrients such as copper,boron,zinc and mgnesium etc. If you are using a growlight, you need to make sure the roots are warm enough or the leaves will fall off as they cant get rid of the heat as the roots are not active enough, you need the roots over 65F better over 70F for normal levels of light , if the lamp is bright/powerfull/close to the leaves you would be better with closer to 85F root temperature.

You're welcome Tracy. LOL, yes it is information overload but you can try using the search box and include pot or potted in your search. Sometimes I have better luck using a Google search and including "Gardenweb" in the search. Your tree in the photo does not look overwatered. The main sign of overwatering is yellowing leaves that drop. Our lemon lives outside on a deck where it gets automatically sprinkled each morning and it does not develop yellow leaves out there. Of course I am in an extremely dry climate. My overwatering problems have all been when the tree is inside for the winter. I hope I have finally learned not to water it too much in the house. My tree is in a much too large self watering pot. That's another thing I learned from reading on the net. I should have left it in the two gallon nursery pot for probably the first two years before increasing the pot size. Another major tip that I got , I think from dcarch, was to use a daylight corrected LARGE CFL bulb for additional light in the house. This is a much cheaper solution than a grow light. I got mine on Amazon and have it in an ordinary clamp light fixture without the reflector. Even though it is covered by shades, it is pretty bright from the outside of our house at night and Max feels it is offensive from the street. I don't think I could get another one for the other side of the tree without a major argument so I rotate the tree, which is on a wheeled stand, every couple of days. Mine is in an East facing window and doesn't get enough natural light. I'll take a couple of photos later in the day of the tree and the food I have been the most successful with. Lee

I agree with the not fed enough thought. Plants will often steal the nutrients from the older leaves to support the new growth and flowers, but it's not good for the long term health of the plant. What brand did you use? It would be better to fertilize on a regular schedule rather than as a occasional quick fix. Osmocote Plus is easy to get and works great for container citrus. Many folks here also supplement with DynaGro Foliage plus. Don't use fertilizer stakes or granular fertilizer, that's more for in-ground plants. I don't use epsom salts (magnesium sulfate)by themselves as it's easy to over or under dose with them. Too much can be a problem. Most quality citrus foods have Magnesium as a micro-nutrient in the correct amount. Also, to me it looks more like a nitrogen deficiency.

That is the very reason I feel so confined to my home until it's time to put all mine outside and hire someone or use a family member to hose them down when ever they want....I don't trust anyone watering mine for that long...I am sorry you lost it and then again you could always start a new) God, just don't let any of the workers from 4Winds see that poor thing, they might have a cry over it..I am sure it once looked spectacular!