HGLTA, HCBTA, HGBTA, HMLTA are all not commonly used abbreviations
BTA=bubble tip anemone
RBTA= rose BTA
LTA= long tentacle anemone
A heteractis magnifica is usually just referred to as a magnifica, a mag for short, or a ritteri.
That being cleared up, I'm not sure that what you had was a magnifica. From the body shape and coloration it think it might have been a Heteractis malu. Magnificas in trouble typically flatten out and get mushy rather than retaining any sort of long shape like yours. The cream on top and red on the bottom is typical of a malu, not a magnifica.
regardless, you need to find the source of the phosphates and water problems. If you are putting phosphates into the tank and using a phosphate remover, odds are you are also putting other toxic stuff into the tank that is not being removed. Also, for anemones, variation of parameters can be more of a problem than high phosphate levels.
The best advice I can give you is to strongly urge that you look for a local reef club rather than a store for advice. Stores (even good ones) are notorious for giving simple fixes which involve buying equipment from them, but don't address the real issues.
Take your time and don't rush into buying livestock and you will have a much more rewarding hobby.
Best of luck
Cindy