Brown dots in sump. What is this?

[Kieko250]

These brown dots started to appear in my sump. Never seen this before. Please help. Tank is about 1.5 years old. It’s hard and I can scrap it off. Any ideas?

 

[fishguy242]

poss sponge??

 

[vetteguy53081]

As your sump collects detrious, diatoms also form. diatoms are some of the most abundant organisms and surface in the aquarium as a brown powdery like substance, within a week or so after a tank finishes its cycle. Diatoms feed on available silicates in your system and will run their course in time. Similarly, because they feed on silicates, anytime you add new sand, rock or something plastic they can pop up.
This should come off easy with the edge of a credit card- just don’t let it reach the return pump which will deposit it in the main tank
Reducing light over the sump will help also

 

[Kieko250]

My tank is 1.5 years old. Diatoms can still form?

 

[vetteguy53081]

My tank is 1.5 years old. Diatoms can still form?

If there is presence of silicates. . . absolutely

 

[Barnabie Mejia]

yes they can, my 29 gallon is 11 years old and I built a holding cage from eggcrate to hold marine pure spheres, I hung it on the tank and after a few days I saw them forming.... rode it out and they went away.

 

[Kieko250]

Thanks for all the info! Should I scrape them off or wait til it dies out?