algae on substrate

[Clint3240]

i am getting a carpet looking algae with a red ish brown color, it is taking over my sand bed. any ideas?

40 gallons
over 1000gph
backpack skimmer
4 inches sand
50 lbs rock
190W light on 10 hours
few haermit crabs and snails, 3 shrip, 2 clownfish, birttle star

nitrate - 0
ph - 7.8
ammonia- 0
salinity - 1.027
temp - 78
alkalinty - 2.8 milli equilavent per liter
mag - 1200
calc - 500

i know my ph is low, for some reason i can not raise it. are these diatoms? i was thinking about getting some macro algae and a in take refugium. i was using tap water and was told not to unless treated, so i started buying the water. i will be getting an r/o.

 

[bawel]

That's diatoms, so please cut your hours from 10 to probably like 6-7hours per day... the longer the hours, it's blooming faster and your snails can't clean it faster than it blooms.

Wait... purplish, sorry I misread... I might not be right... experts chime in please...sorry....

 

[Clint3240]

i was thinking about cutting the light for 2 days and then shortening the time it is on. i added a picture in my first post to help. i guess you could say its a little more red-brown than purple..my mistake, i changed it above

 

[roka64]

Diatoms are nothing to worry about, they will burn themselves out. They thrive off of silicates and light.
I would be more worred about the cyano (red) that looks like it might be taking a hold.

 

[Clint3240]

it grows so fast that if i remove a dense part of it, it grows back just as thick in a few hours

i have a ro/di in the mail as we speak

 

[Clint3240]

if its this cyano, how do you get rid of that?

 

[roka64]

Additional PWCs, less light, more water flow to those areas, less feeding.
I feed every 2 days and sometimes every third day.

 

[melosu58]

It looks like the beginning of cyano to me. Read this

http://www.aquariumadvice.com/articles/articles/20/1/Cyanobacteria-AKA-Red-Slime-Algae-/Page1.html

 

[Snookster]

I'm fairly new to saltwater and I was pretty much farming the stuff. I got some red leg hermits and some astrea snails - they're mowing through the stuff like it's candy.