I had heard and seen horror stories of this item scratching the inside glass of your aquarium .  There are techniques and ways to prevent that from happening especially if you are using a sand substrate .

WHAT HAD HAPPENED FOR ME WAS NOT THE CASE

THIS ITEM SCRATCHED THE OUTSIDE OF MY AQUARIUM GLASS.

WHY ON GODS GREEN EARTH CAN SOMETHING LIKE THIS HAPPEN???

I noticed the felt on the bottom of the outside layer WAS NOT ALL FELT MATERIAL.

There are small gaps on the CORNERS that are just PLASTIC and when I run my fingers along the corners.. I can FEEL a SHARP SCRATCH.

This ended up SCRATCHING MY OUTSIDE GLASS OF MY AQUARIUM...

I am SO DISAPPOINTED, DISATISFIED, AND REGRETFUL THAT I BOUGHT THIS PRODUCT.

See my photos and you can see this damage done.

I CANNOT USE THIS ITEM and STRONGLY DO NOT RECOMMEND THIS PRODUCT..

I do not recommend this to anyone. Just take a scrub and sponge to clean your tank...

Very pissed off about this whole ordeal.
I had heard and seen horror stories of this item scratching the inside glass of your aquarium. There are techniques and ways to prevent that from happening especially if you are using a sand substrate. WHAT HAD HAPPENED FOR ME WAS NOT THE CASE

THIS ITEM SCRATCHED THE OUTSIDE OF MY AQUARIUM GLASS. WHY ON GODS GREEN EARTH CAN SOMETHING LIKE THIS HAPPEN??? I noticed the felt on the bottom of the outside layer WAS NOT ALL FELT MATERIAL. There are small gaps on the CORNERS that are just PLASTIC and when I run my fingers along the corners.. I can FEEL a SHARP SCRATCH. This ended up SCRATCHING MY OUTSIDE GLASS OF MY AQUARIUM... I am SO DISAPPOINTED, DISATISFIED, AND REGRETFUL THAT I BOUGHT THIS PRODUCT. See my photos and you can see this damage done. I CANNOT USE THIS ITEM and STRONGLY DO NOT RECOMMEND THIS PRODUCT.. I do not recommend this to anyone. Just take a scrub and sponge to clean your tank... Very pissed off about this whole ordeal.