Wow does this sound familiar. I had the 8g biocube and for over a year I couldn't keep but one type of zoa. Every zoa aside from that one melted within days of adding them to my tank.

I never did come up with a concrete answer. Many here tried to help me also. Some suggested that the tank water was *to clean* others said it may have something to do with it being a *closed system* she will notice she has very little top off that's needed. Some also said it may be the lighting~cf.

Either way ever since I upgraded to my 26 bowfront I've not had one issue with keeping zoa's. What am I doing different with it then I was the 8g? Well for sure I'm topping off at least 2g's a week. I've got a great little fuge filled with cheato. I have a little skimmer also. My lights are now t5's. Instead of the weekly water changes it's more around the 10-14 days. My parameters are more consistent also. I can also feed the tank more since having the skimmer.

I know she can get a skimmer for the 29g. I don't know which 29 she has, cf or mh? Better surface agitation and o2 exchange. There is one reefer here whom I know has the 29g mh. JimsFlies is his name, look him up and see what he's doing as far as zoa's go.

Good luck.