It's me again need a ID

[seeds369]

I'm guessing this isn't good to have growing on my rocks but I don't know what it is or how to get rid of it. I am currently fighting with hair algae and wonder if this goes hand and hand.

[54seaweed]

the blue looks like sponge but its hard to see for 100% id my eyes are going waiting on my new glasses

as for algae large water changes to remove nutrients from water column ,
do you use RO/DI water

you can use a tooth brush to remove hair algae during water change

[Sniperhank]

Both appear to be sponges.
I wouldn’t say hand in hand, but a lot of nutrients in the water column will lead to lots of filter feeders like that.

[seeds369]

Originally Posted by 54seaweed

the blue looks like sponge but its hard to see for 100% id my eyes are going waiting on my new glasses

as for algae large water changes to remove nutrients from water column ,
do you use RO/DI water

you can use a tooth brush to remove hair algae during water change

I’ll try larger water changes. I use zero water during my changes. I’ll try once a week also instead for every other. Thank you for your help.

[Sniperhank]

Zero water? As in from the commercials on TV? Well, I personally struggle with their claim of 0 TDS from a set of filters without something like a DI resin involved to remove the remaining impurities that filters can't touch.
Though with that said, I'd say that water source is 10x better than tap water.
That said, algae still feeds off of light and nutrients in the water column. Can't live without one, so there are nutrients in there...most likely in the form of phosphates that are tough to detect on a hobby level. They would either come from the water source itself or simply aren't being exported from the system after being added from when you feed your tank.
The large water changes will get you in the right direction. Just remember that even a 50% water change will only cut the levels in half, not remove them totally. It will take a series of large water changes along with manual removal of the algae to solve this issue. It takes time, patience, and in the end some frustration.

[Wwidener]

I have this on my rock also. My LFS store guy has 20 years in the industry and said it is a nuisance sponge and will not hurt anything. He said it will take over coral but will not kill it. Take a toothbrush and scrub it off.