@Michael Hans
I have some hammer coral that grew in another tank that’s at a school in Berkeley that I would like to donate to your tank
Hit me with a pm
I would save some of it for a different location
But to kill it, you pull the plug and brush the sponge off and rinse with FW
The combination of air and FW should kill the sponge, IF undesirable
Over the past 25 years, this has been the brand I’ve used the most...
https://hdltd.com/p_tribase.php
Because I do NOT test anything, I cannot vouch for the information on the above site