Gooey stuff on rocks

[ckyuv]

I have been away from the house the past couple weeks and came home to a bunch of gooey stuff on the rocks. It started in small amounts after I started to dose phyto(I think, maybe just coincidence) but even after I stopped dosing the stuff is growing. 
 

siphons off easy as pie, so mostly it’s just visually annoying. I’m chalking it up to me finally getting the uglies in this tank(it’s about 6 months old) but curious if anyone has had/seen this before. I won’t lie, I don’t own test equipment stuff aside from temp and salinity. I might take water up to RCA to test as I’m kinda concerned the dry rock is maybe just leaching crap. 
 

I did have a hammer and a red dragon die while I was out of town but I’m assuming that was due to ato running dry for a few days. 

[Timfish]

I'd guess some cyano like Lungbia or something similar (what I reffer to as "snot" algaes).  As an aside, you definitely need an alkalinity test kit, API is super cheap and easy and when I compared it to two Hanna testers more consistant and as it is about twice as sensitive as the meq/l standard used by many researchers it is more than sensitive enough.  Calcium, pH,magnesium amdPO4 would be helpful too but alkalinity is the one I use frequently.  Use steel straws to siphon it off as frequently as you can but I wouldn't do more than 10% water change at a time.