Hey guys. What the title says. I tried with 2 sps and their tissue receeded and one of them died. The other one is being bullied by my hermit crab. I just need to glue it back down. But, why does the tissue receed? Is it because i bought it online. Should i go to a proper shop and buy it myself? Also, i need help with choosing a SPS coral. Something easy. You can find info about my tank on my build thread. Here is the linkie, https://www.reef2reef.com/threads/my-20g-reef-tank.1138047/. But basically the flow is 2, 3000l/h wavemakers. I have a total of 50w lighting. 20 gallon tank. Please help.

, interesting. But why does the tissue receed. I dont suppose it is because of too little light right. Plus i thought 50watts of light was too much as most of my corals are positioned a bit far from highlight places. I know it reaches like 800 par on the surface of the water. Of course, this was using a phone app that i dont think is too accurate, and par can change depending on how many particles are in the water etc etc. I think i might try again with some easier to keep sps. Last time i was succesful at keeping an orange digitata, until a fireworm attack, and then a gha 'attack'. But i think i will try again with that.