Help!!!!

[e46er]

my tank has a massive problem right now and im freaking out im going on holidays next saturday morning for 17 days and my tank is falling apart


its been stable for probably 2 years and one of my dosing pump motors crapped out and i didnt notice for god knows how long probably a week to 10 days it was the alk pump
so my alk dropped to like 2.5 dkh my calcium somehow managed to climb to over 600 my mag also climbed to 1500

i know have red algae on like 1/2 my sand and my 2 prized corals are very unhappy my GBTA which is usually 12" or so is now hiding in the corner closed up my 18x18x18 green birdsnest is now slowly going white on the lower branches the ends are green but the rest is brown its always had a little ****e in the middle i always assumed it was lack of light but now its farther out is this STN???????????

my parameters for 2 years

cal 420 elos
alk 7 elos
mag 1350 elos
sal 1.026 refractometer
temp 78 controller
phos 0.00 hanna meter


now its
500 ca salifert
alk 8.3 salifert
mag 1500 salifert
rest read the same but i know i have some phoshate as i now have algae

in the last 3 days ive done 2 40-45 gal water changes
but my salt is mixing up at 500 ppm cal
ive disconnected my cal dosing pump the alk is back online but the calcium doesnt seem to be dropping

tank is 120 G display 40 gal sump vertex 180 skimmer 2 250 MH snapper return also running carbon and GFO snapper CL.

what do i need to do? my anemone and birdsnest are my favorite corals i have and theyre huge and i dont want to lose them but im leaving next saturday for 17 days!!!! ugh could not have happened at a worse time does it sound like i need to frag my birdsnest ???