Ferropol is an Fe + trace product (also has extra K). Similar in function to Flourish, CSM+B, TMG etc.
I've tried it in the past and find I get better results with the other products.
And JBL, while it has some very good products, is another one of those European companies that refuses to list the exact contents
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It's difficult to tell from the pictures what exactly this is but could be diatoms. Read some of the links provided by others in this thread and you probably do need to take a look at adding nitrates and phosphates... in small quantities though as you don't have that much light...