D'oh!

[Anonymous]

I have a diatom spike going on right now, it is really bad. My question is, I just did a 8 gallon water change on a 27 hex with 35 pounds of LR. I never used RO water before, and now I am using RO from a brand new coralife 24 gpd RO filter. I don't skim, but usually change 5 gallons every 1-2 weeks. I have a maxi jet 1200 for circulation and an empty eheim for a pseudo-refugium. What can be causing my diatom bloom, when I haven't had one for the 10 months of heavy coraline algae growth? I haven't checked my nitrates, because I figured with 5 gallons coming out every 1 or 2 weeks, there shouldn't be any.

 

[Simon1]

IMO, five gallons every week or two is not enough for a tank that size when you have an algae bloom. Have you checked your phosphates ? How old is the tank ? Everyone is also going to want to know your nitrate level as well. You may also want to get a TDS meter to check the RO that you are producing. I was fighting diatoms for a while, and it turned out to be silicates in my water. I used Kent Phosphate sponge (also removes silicates) and the problem cleared in a week. Hope this helps.

 

[Len]

For the purpose of dilution, you might want to aim for 10 gallons semi-weekly or monthly. But algae tends to work in mysterious ways If it's a sudden diatom bloom that you haven't experienced before, and if you haven't changed anything significnant about your tank to cause this bloom, you might want to give it one or two weeks to settle down on its own. What I did with my sudden diatom explosion is to let it grow out for 2 weeks, then I took a small powerhead to the rocks and glass to blow off the diatoms. I had a filter sock in my sump to catch as much of the diatoms as possible (you can fill your eheim with mechanical filtration). After 24 hours, I removed the filter sock. The diatom levels returned to normal thereafter.