What I'm learning during my cyanobacteria outbreak.

[Rabe]

I have just gotten through a pretty ugly cyanobacteria outbreak.

I set the 120 gallon mixed reef tank up with tap water. I knew using tap water I would be introducing some nasties, but I had plans to buy an RO/DI unit.

I cycled the tank and it went well. I put in a light bio-load of 9 fish, some shrimp, snails, crabs and 4 zoanthid frags. At this time, I just tested basic marine parameters. I have a refugium in my sump that always produces massive amounts of chaetomorpha, about 4 gallons in a month.

So I knew, that phosphates were being introduced into the tank due to my tap water source.

Mind you, nitrates always tested 0 after my cycle, and they still do.

Fast forward to the 2.5 month mark, and my glass cleaning, of an ugly brown film, has increased to every 2 days, sometimes every day and cyanobacteria has started showing up, in small areas around the tank along with a couple patches of turf algae. Again, the nitrates measure 0 with my API test.

I decided that it was time to buy an RO/DI unit to filter my tap water. So I bought one, and started topping off with with RO/DI about 2.5 gallons per day. I told myself, everyone goes through an ugly phase and this is mine. No one knows why the ugly phase happens, but it does.

My glass cleaning and cyano didn't show any signs of receding and actually got worse. So bad, that I had to bubble scrub every day while I blasted the rocks and sand. This helped getting the gunk into the filter socks. It was apparent that I was fighting a loosing battle.

About 2 weeks ago, I decided to buy a Hanna phosphate checker. I check the tank and low and behold.... 0 ppm PO₄. And of course... 0 ppm NO₃. So at this point, I'm like what the heck is going on? And then I decided to trace the water back. I tested the tap water, 1.5 ppm PO₄, I expect that. I draw a few cups of water from the output of my RO/DI unit and sure enough... 0.3 ppm PO₄.

So there it is... My unit isn't removing all the phosphates. Now I'm ticked. This unit has only produced maybe 50 gallons total. So I look into this manufacturer, and my purchase on eBay... Low and behold... It's just an RO unit... No DI. So... I bought the wrong thing... Well.. An easy enough fix.

Last Thursday, I bought some chemiclean and dosed it per instructions. And that has worked as described. No more cyanobacteria. No adverse effects to my zoanthids nor my fish, and I have a twin spot / 4 wheel drive goby. Supposedly, they are difficult but I can't tell.

What have I learned so far during this outbreak? The biggest thing is that testing only shows the 'excess' of the parameter in the tank. Not an absolute, "this is what has been in the tank." It doesn't show what the algae or corals are consuming.

In my case, it's obvious that my tank had phosphate introduced but it was being consumed! If I only consider test results from the tank, I would be dumbfounded as to why I had cyanobacteria everywhere and turf algae in a few spots.

So, to underline: Don't focus only on the test parameters from the tank. Look at what the tank, as a whole, is also telling you. There's turf algae and cyanobacteria? There has to be a nitrate and phosphate issue. Just has to be.

 

[Sashaka]

Hum... Your post has me thinking about the current tank problem in my 180 gal FOWLER. I don't know if I have cyno or dinos or what. I just purchased a microscope to figure out my tank muck mystery. I do know I over feed and that's a big part of my problem. I don't have corals in my FOWLER, so I wasn't too worried about having higher nitrates, until the bubbly muck covered my tank!

I try to stop myself, but I can't seem to kick the habit. It's the curse of the hand having a mind of it's own. My brain tells my hand to feed sparingly, to only feed what the fish can eat before it falls to the bottom of the tank, but my hand ignores this good sense. I have a few "hiders" in the tank and I'm always worried that they won't get enough to eat. So... I broadcast feed and now I have high nitrates. I do 30 to 50 gal water changes every week, suction out as much muck as I can, and I've started adding No3Po4x Algae Management.

Adding the No3Po4x Algae Management is finally lowering the nitrates, but the muck continues to cover EVERYTHING in one week's time. I'm exhausted trying to keep up with it and it's sapping all the fun out of watching my fish. I also worry I might have the toxic kind of slime as well and my fish might be hurting because I can't get rid of the stuff. I used to use Chemiclean but stopped because it was so expensive to buy for all my tanks. I need to rethink that decision I think.

After reading your post I realized that I've probably been adding phosphates and other nutrients using well water in my tank. I can't make enough RODI water to keep up with the nitrate problem, so I've been supplementing the RODI water by using some well water when I need a few more gallons during water changes. I'm sure it's not the only issue, but it's probably one of the problems.

I thought my well water was fine because I use straight, untreated well water in my one 29 gal. tank without problems, and I've had it going for years with no issues, but a water change for that tank is much larger. I usually replace 8 - 10 gal each week. Ding, ding, ding! I'm exporting the problem as fast as I'm importing it so I don't have the same algae problems in that tank as is showing up in the 180 gal. At least that's what I now think after reading your post.

I need to rethink the size of my Brute garbage can water changing station...but that's a summertime job when I'm home and have more time. I also need to figure out how to get the hand to listen to reason and stop overfeeding!