I have one miniature named Ally's Rosy baby, it has pretty pink flowers and cute little heart shaped leaves, I'll have a good digital camera in a few days here and I will be able to send you pictures, I also have one called Leprechaun's Day dream which has stayed small for a very long time even though it's in a pretty big pot, so I think it might me a semi-miniature too. I'd trade leaves with you if you'd like, I'm looking for new flower colors so if you have any light purple, white, or yellows that would be awesome.

Your plant looks healthy. Repot with new soil would be my first suggestion. Sometimes heat kind of makes old leaves go brown and limp. I had a few plants show the same 'glassy' brown leaf drop. I keep the central air on all the time when it's hot, but occasionally open windows to air out the house. And I enjoy the heat once in a while. If more leaves would of dropped, turned rotten- I would of said too heavy soil, overwatering. But, your plant looks ok. Outer leaves die naturally- so it's expected. Variegated plants love cooler temps or they lose the variegation. So, you seem to be doing everything ok. ;) Deb

Some past tips have been to let the plants dry out (larvae live in the damp soil), putting a layer of sand on top of the soil to discourage the egg laying, sprinkling cinnamon...none of them worked for me when I brought home gnats in a new prayer plant and they invaded every plant in my home. What did work was buying a package of mosquite dunks, floating a piece of the dunk in a container of water overnight, then using it to water my plants. The BT in the mosquito dunk kills the gnat larvae and stops the cycle...it may take more than one treatment if the infestation is heavy. The same BT (bacillus thuringiensis subspecies israelensis) is in Gnatrol, & Knock Out Gnats, probably others...I just found the dunks better priced locally (and passed the rest of the package on to a friend with a water feature in their garden)

I never quite understood why you'd need vermiculite if you're wicking. Except it gives you a bit of a buffer between the reservoir going dry and the pot drying out completely... I use sulfur powder (garden sulfur from Canadian tire) against mildew and it's quite successful. I've also read you can microwave your soil or rinse it before use and that'll get rid of mildew. Haven't really tried it myself... My wicking mix is about half and half perkite and potting soil. Have tried several and wasn't 100% happy with any of them. Seed starter makes your plants stay small, promix A/V and MG have too much fertilizer etc. My best results yet were with the blue bag of potting soil from Schultz. Moisture control I believe. A friend of mine uses it straight up for wicking. I don't dare.... As for 2 or more ply yarn, I don't believe that should make a difference. If your mix is light enough, anyways. If it isn't, limiting the water supply via small wick might help, but it wouldn't be dependable. Fwiw, your brown spots look like water marks to me... the curling under may be a reaction to PH or light...