Not that I am trying to raise them, far from that~ I have the green hair like algae growing on the back of my 24G that houses my seas horses and Manderin, it is VERY thick. I have been testing the water for 3 weeks and the Nitrates would not surpass 10. I know the test is valid as I used it on my FW and eel tanks and they registered where they usually are between my WC's. To be sure, I took my son`s kit and retested just to be sure. Since Nitrates don`t exsist in the ocean, I always wondered why and assumed something has to be eating, processing them. Sea Fans and other marine life had to be doing this. My question then is, is it harmfull if I keep it just to the back of the tank. I clean the tank sides and face daily so it does not spread. It kinda looks good too in my opinion, better than the black plastic of the cube, gives it a more natural look. Thanks as always gang and look forward to the reply`s...BTW, my Manderin spends alot of time in the `Grass` and seems to enjoy hunting in it...I keep the salt, calcium etc levels up with doses of the Marin stuff...