That was my concern too, do they spend most of the time in the rock piles or the algae? Have you experimented with moss? Hoping they eat algae/microfauna in java moss. Still don't have much algae-- I threw in a wafer to seed algae and all it did was make the water brown lol.
I just did a little rescaping, will post a pic soon.
No luck with breeding. I think I lost a few. Not sure how many I have left. Though I see some from time to time picking on the lava rock. They seem to enjoy being in the dark nooks and crannies between the lava rocks than out in the open. The MTS are breeding like crazy and 4/5's of the tank has been smothered by green hair algae. I'm thinking about rescaping when I find a some decent pieces of black lava rock or lace rock.
What type of hydrometer are you using? All of them are pretty inaccurate, but the plastic box type are REALLY bad- they get worse over time. If I ever make it to one of the meets bring a sample of your water and I will bring my refractometer and check it for you.
You should pick up a few pieces of dry live rock, better than the lava rock... It is a 2.5 gal tank, right? I may have a few pieces I can spare from my 180 Gallon reef sump.