I Think I Have (Bristle) Worms, Eco-Aqualizer Question I think that I have bristle worms in my tank.  <<Not unheard of.>> My Live rock is loaded with them.  <<Ah, EXCELLENT indicator of husbandry (lack thereof), detritus levels. The worms are there in large numbers because they have plenty of food.>> I have taken a picture of one that I caught.  <<Not by hand, I hope. Bristle worms look similar to fire worms, NOT fun! Both can leave these very fine hairs in your skin, not entirely unlike some species of cacti. (Yes, I have been stuck, left little bumps in my finger for YEARS!)>> My question is this, are they harmful to the tank or should I just leave them in the tank?  <<No, they are not harmful at all. There are those who will assert that they can eat your Tridacnids, some corals, etc., but they are misinformed. Bristle worms are specifically detritivores (detritivores?), they eat dead and rotting stuff. Of course, there are species that may attack desirable specimens, but these are not an indicator of tank health/husbandry, and don't usually appear in the large proportions we see with bristle worms.>> Are they beneficial and if so how do they benefit the tank?  <<They're quite beneficial, especially if you haven't got a handle on the detritus, as they will actually help prevent a huge buildup of nitrate within the system by their consumption. However, they're not very pretty, I personally don't find them desirable (not after having been stuck), and would address the husbandry here to get their numbers down. All such issues are posted here on WWM ad infinitum.>> I have attached two pictures.  <<Good shots.>> I am also wondering if anyone knows anything about a product called Molecular Ionization which is an inline Aquarium ionization device. Their web site is www.ecoaqualizer.com  and the product is Inline aquarium ionization.  <<Just reading the drivel on their site gets my hackles up!>> It is supposed to clean the water and help prevent disease and algae growth. <<This product is useless, a waste of time, money, effort. If what they claim were possible, why are municipal water districts not using it? Go to reefs.org, search this product, learn what a hoax it is!>> Thank you, Kathy <<You're welcome, Kathy. Spend your hard-earned on a good protein skimmer, instead. Stay away from these products that promise the world based on pseudo-science. Marina>> P.S. A big hello to Bob Fenner!!! I have not been in this forum for quite a while.