hello there and welcome today I'm talking about brown algae in marine aquariums otherwise known as diatoms so firstly they're not actually an algae they're their own type of organism and they have a hard skeleton diatoms usually appear in new marine aquarium setups or ones where you've added extra nutrients to the water if you added some new live rock or some more sand diatoms are a completely natural normal thing to have appearing in a marine setup and are usually the first in the chain when cycling and maturing a new tank however diatoms can be really unsightly and they can actually take over the entire tank covering every surface in a brown film they can even cover corals and sometimes they can kill off certain types of soft and hard corals which is obviously undesirable in your marine tank the actual cause of diatoms in any aquarium is usually hard to nail down they usually caused by a variety of different problems the first thing you need to look at is your lighting if your lighting is incorrect it's not marine lighting then generally change that over to a marine bulb or marine LED can help also it could be that your lights are on for too long and possibly that they are too intense for your aquarium so make sure your lighting is correct diatoms also are caused by excess nutrients like most algae they'll soak up whatever's available but they very very much like silica and silicates in the water and dissolved organic compounds those two are the main nutrients that diatoms will use but also nitrates and phosphates of food as well so silica can come from using unfiltered fresh tap water so if you're not using our Roe in your aquarium then that's a possible cause also if you don't use correct sand or your added new live rock silica can also come out from there make sure also that any of your saltwater using is not a salt mix that's high in silica a way to reduce the amount of silica in your aquarium is actually to promote the growth of sponges or even to buy some sponges because sponges will out-compete diatoms for silica and then once the sponges are growing the diatoms will go away phosphates and nitrates in the cream is very common especially a marine aquarium to get rid of those you can use the usual kind of absorption based media's or you can use some liquid form of dosing such as a chemical called no pox and that should reduce the amount of phosphates and nitrates in your aquarium also reducing feeding can help and also don't overload your aquarium with livestock any good marine aquarium would be lost without a good cleanup crew these will also take diatoms many of the best diatom eating and organisms are trochus and astrious now so you'll probably just know them as turbo snails but they will happily graze around on your aquarium rock work and eat those pesky diatoms fish such as cole tangs or any other kind of icon Thurid aye or ten Akitas type fish will graze on diatoms or any other algae so it's worth adding a variety of tang another thing which can be good for diatoms is the algae blenny because they will go around and graze basically you want a good grazing community within your aquarium of course that won't hit the cause of the problem which is generally over nutrients but it will help to reduce the visible problem even hermit crabs are a good option so these are all ways of getting rid of or reducing the amount of diatoms in your aquarium but remember diatoms are a natural part of the ecosystem the reason you've got too many of them is because you're promoting them essentially the nutrients are there to feed them also if it's a aquarium it's just part of the cycling process saying see what you want to do is promote the sponges get a good cleanup crew make sure your nutrients and water quality is good and eventually the diatoms should die back it's a normal process if your tank is mature though and you're starting to get diatom blooms you really need to look at the reason why what has changed or what is causing that diet on to take over and usually it's a lighting or a nutrient problem so I hope this has been helpful I hope is also going to help you with your diet on problem so thank you for watching and happy fish keeping