Help!

[BillyBay]

We have had this saltwater tank for 5 months, every level is perfect, we use RO water, and all of a sudden we have all this red algae growing everywhere, is it good? Bad? What is it? :-(

 

[200 gallon reef]

It is hard to tell but it looks like cyno to me. What do u feed the fish and how often?

 

[BillyBay]

I feed the fish once a day with misces , I make sure I feed them a bit at a time so none falls to the bottom, I don't have many clean up crew, but it's just been in the last couple weeks it is spreading like wildfire, and it's going on my sand too, I always check my levels, the fish are super happy, but the weird thing lately is all my snails are dying. But that is the only thing that won't stay alive, so I'm scared to buy a cleanup crew, even one day after I bought a sand sifter star fish last week and 2 days later it died, also bought 3 scavenger snails at the same time and they died too, I just bought an RO filter to see if that's the problem, I have only done 2 -25% water change so I guess there is still some tap water left in there, I'm just stumped.

 

[200 gallon reef]

The tank is how old? But you said u just started using ro water?

 

[BillyBay]

Yes my tank is 5 months old, and yeah, I just bought the RO filtration system 3 weeks ago, this red stuff was creeping up slowly, and now it is outta control . I got the RO system because I thought that maybe all the bad chemicals from tap water was building up in my tank, and heard Tao water is the worst for saltwater tanks, like I said my fish have never been healthier looking, but this red stuff is taking over and I don't know why my snails are dying , I have 20 hermit crabs and a few emerald crabs that are still alive from the beginning so I just don't get it

 

[200 gallon reef]

Yes, tap water is one of the worst things to a salt water tank. Do u have any powerheads? If so what size?

 

[BillyBay]

I'm not exactly sure the size, i know I totally sound like a noob, but it's the third size up I think it's a 425?

 

[200 gallon reef]

Do u have one, two?

 

[BillyBay]

I just have one

 

[200 gallon reef]

What size is the tank?

 

[BillyBay]

It's a 49 gallon with a 20 gallon sump