Algae Problem

[Steve9877]

Hello,
Hopefully someone can help me out. I have a 125 Gal reef that has been set up 6 years. Recently Ive been having either an algae or diatom problem. My rocks and gravel get a brownish coating of gunk that looks like a light layer of mud has settled onto them. It can easily be brushed off the rock with a toothbrush. After it has been cleaned away it comes back quickly. Probably within a week or less.

Ive tested for phospate and nitrate and they are both very low. My Ph is low at about 7.9. I just changed the elements in my RO/DI unit in may. I have vho lights and the bulbs do need to be changed, they are 18 months old. Other than this my bio load is fairly low. I have about 11 small fish a few crabs and a few snails

Anyone have any ideas to help me out?

Thanks in advance,

Steve in Louisville

 

[kmk2307]

Steve,

It sounds like cyanobacteria. Phosphate should be undetectable. What kind of filtration do you have? Do you have live rock? What kind of substrate do you have? Do you keep corals? Do you grow any macroalgae like Caulerpa? I think it is recommended that VHO bulbs should be changed every 12 months. How much total VHO wattage do you have? Though you have a large tank, I don't know if I would consider eleven fish a small bio load. Do you have a picture of your current setup? Please answer the questions I asked and I will try to give you advice if I can.

Kevin

 

[JRoweNole]

Based on my experience:

Check your ALK levels, keeping them a little higher than sea water levels (2.8 mq/l)

Check Magnesium levels

Siphon the stuff off

Stay consistent w/water changes

 

[billsreef]

Boosting alk and pH can help. Any level's of PO4 high enough to detect are too high. So perhaps increasing nutrient export with better skimming or growing macro's in a fuge would be benificial. Phosphate remover's are another option. Also diatom grazing snails such as astrea's and turbo's are quite usefull for control.