There's this white stringy stuff between 2 live rocks and also between the Rock and back glass. You can barely see it. The pics aren't great either. They seem rather crusty, and easy to scratch off but impossible to reach. What are they? Are they safe? What are they and should I bother getting rid of them? ![ImageUploadedByAquarium Advice1460408304.740896.jpg ImageUploadedByAquarium Advice1460408304.740896.jpg](https://www.aquariumadvice.com/data/attachments/245/245778-10629c5e40022992575bbf197f33349d.jpg)
![ImageUploadedByAquarium Advice1460408321.589195.jpg ImageUploadedByAquarium Advice1460408321.589195.jpg](https://www.aquariumadvice.com/data/attachments/245/245779-2a0786210a5859e110794e61f8feed04.jpg)
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![ImageUploadedByAquarium Advice1460408304.740896.jpg ImageUploadedByAquarium Advice1460408304.740896.jpg](https://www.aquariumadvice.com/data/attachments/245/245778-10629c5e40022992575bbf197f33349d.jpg)
![ImageUploadedByAquarium Advice1460408321.589195.jpg ImageUploadedByAquarium Advice1460408321.589195.jpg](https://www.aquariumadvice.com/data/attachments/245/245779-2a0786210a5859e110794e61f8feed04.jpg)
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