White cover on marine sponges?

[spongepants]

I had some sponges dying in the aquaria within a couple of days. They were covered with a white layer that looked like some kind of fungus and the tissue was dead (soft and black). We fed them with Spirulina (dry microalgae) twice a week but didn’t measure any parameters, such as nitrate, ammonia, Oxygen etc.,. Does anyone has some advise on what this could be and what did cause the death of the sponges or maybe someone has had the same experience? I really appreciate any advise, thanks!

 

[gemmy]

How long were they in your system? Were they exposed to air?

 

[spongepants]

They were in the system 6 days before the first contamination was discovered and we never exposed them to air at all. We fed them twice in a distance of 2 days with Spirulina (dry microalgae) in a concentration of 0.83g/L and changed the water every day.

 

[flower]

Sponges are difficult. They can't be exposed to air, you can't expose them to light or they get clogged with algae. You have to have very strong water flowing across them to feed them. They need dirty water to absorb the nurients from it...if the tank water is too clean they starve, They grow best in the dark, and what fun is that in a fish tank.