Odd organism growing in sump

[taylorspinuzzi]

Hello all. I have seen a weird transparent organism growing in my sump. I first noticed it growing in my in tank hydrometer but now it’s in my sump. My tank perimeters are perfect and my tank has been running for 6 months with no issues. The organism looks like a stalagmite growing only on my live rock in my sump. There is nothing in the tank. Should I be worried or is it something that is just there? I tried to take the best pictures of it but they are super small

 

[little_sardines]

It looks like sponge to me - IME its good to have, shows the tank is maturing