White bits on the surface

[LLG]

Suddenly some bits of white stuff appeared on the water surface in my aquarium. They look and feel (when I crush them) exactly like Perlite, those white bits they put into houseplant potting soil. They are mostly in the corners or around the glass but there are a few floating freely.

Ideas? Thanks.

 

[dcutl002]

Interesting. Is your substrate dirt?

 

[LLG]

It's standard commercial fish tank gravel with a thick layer of sand. I have very hard water but can that really be the reason? They appeared so quickly, too.

 

[dcutl002]

If you use commercial tank gravel then it might be the "coating" that they put on the gravel: it is a type of paint. I do not think that it will hurt anything, but I would get it out the best that I could.

 

[LLG]

I had no idea the gravel was coated with anything! I did rinse it well before using it but never thought there would be anything to rinse off except dust. What is the reason for a coating?

 

[dcutl002]

The coating keeps the gravel looking clean, so there are no pores in the gravel for algae to cling to. I usually go to places like Lowes or Home Depot and purchase natural, untreated gravel because it:
1: is cheaper
2: has pores that natural bacteria can breed in
3: gives plant roots something to cling to

It is kind of hard sometimes to find the right size natural gravel at a hardware store garden center, but every now and then I get lucky. I usually look for gravel bags with 2-5 millimeter pebbles. Now, there are companies that make "natural" aquarium gravel, but it is expensive.