So you use ro/di, still got algae: where's the stuff coming from? An FYI


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RC Mod
In a word---phosphate. And please pass this on.
Corals don't like it. Fish aren't fond of it. And in the presence of phosphate, hair algae takes off in huge sheets and nastiness. Film algae forms on your glass. Unwanted macro takes off and chokes things.

So where's it coming from?
Number one source: water. Tapwater is treated only to remove what makes it unfit drinking water. Phosphate tolerances for US are quite high. Got the picture? Your tapwater may or may not be loaded with it and other things we tolerate.

Number two source: sadly, live rock. Live rock may bring in phosphate. You have to have it. There you are.

Number three source: bought algae---as fishfood. Even dry red flake or pellet fishfood has it. If you are feeding a herbivore, you are importing stuff that has phosphate in it. Kind of ironic: you get a tang or lawnmower to eat the algae you don't like, and when it runs out, you add more algae to feed the tang or lawnmower. Unfortunately corals really don't like phosphate. This is a problem.

And never mind buying a phosphate test: it will almost always show negative if you have a lot of algae. Why? It can't 'read' phosphate that's bound up in the algae. So save your money: if you have algae in your display, you have phosphate. When it gets loose from the algae, it harms your corals. It's a vicious cycle.

Now that I've delivered depressing news---how do you fix it?
There are chemical absorbents, an iron preparation called variously Phosban, Phosguard, etc. These are ok. But my favorite, and the one that works best, is setting up a meaningful fuge.
Lit 24/7, its algae, usually cheatomorpha, sucks up the loose phosphate that decays out of the main tank and makes it harder and harder for algae in the main tank to make a decent living. Eventually it gets discouraged out of existence. If you do have an algae-eating fish, it grabs the phosphate released by that fish's poo and does not let all of it get back into your display tank.

Once you understand the transaction, you see how it works: the fuge 'binds' the algae up, you keep cutting your cheato ball in half and selling half of it off, or just tossing it, and your water stays phosphate-free.

A fuge CAN'T outcompete tapwater. You have to improve that. But if you have an algae-eating fish, get a fuge going, and you should be in great shape to maintain healthy water, feed your fish, and even raise some lowlight soft corals like mushrooms (saying you have low lighting). If you have high level lighting, no reason you can't get such corals to thrive right alongside your fish. You'll have better than average water and one of the biggest reasons corals don't thrive in some tanks will just be cleared up to a no-problem.

Long post, but HTH, friends, so you understand why we keep saying "refugium."
You said you run your refugium 24/7, is there any benefit to that compared to a regular or even reverse lighting cycle? Right now I am running in reverse because I have heard this helps with PH swings but if 24/7 is better I can make the switch.
<a href=showthread.php?s=&postid=12844348#post12844348 target=_blank>Originally posted</a> by OAD
You said you run your refugium 24/7, is there any benefit to that compared to a regular or even reverse lighting cycle? Right now I am running in reverse because I have heard this helps with PH swings but if 24/7 is better I can make the switch.

Excellent question. There is no benefit to running a fuge 24/7 unless you employ a type of macroalgae, like Caulerpa, that can go sexual and foul your water. By running the lights 24/7, you can reduce (not prevent) the possibility that the Caulerpa will go sexual. If you use something like Chaetomorpha which does not go sexual, then you need only light it 12 hours a day and doing so on a reverse daylight cycle will help stabilize O2 and pH.
actually some say yes, some say no. The latest report is no: a small dark period benefits the algae. Mine is very, very dark green, so I'm doing ok. Don't see how it could grow faster. But I should actually amend that to about 20/7.
I understand you're right about the ph swing: that's not a problem in my tank, thank goodness, but if it is in yours, I'd say do as you're doing.

And yes, one of my reasons is that my cheato ball has caulerpa in it: the cheato outcompetes it, but it's a pest, and dangerous. If you have no caulerpa, a rest period is going to do you no harm.

I do keep a spare lightbulb so I can be sure the stuff behaves. It's that serious for a tank.
Wait a sec, the Chaeto colour matters? All the growth on my Chaeto is light green, does that mean I should tone down my lighting period?
abulgin, that is what I figured: I will continue running my lights on a reverse cycle. Thanks for the write up sk8r.
I use a reverse cycle 18/10 with chaetomorpha a garacilaria.
FBNitro, if it's growing, it's good. i do note that when mine gets stressed it goes lighter.
Yup, it grows but I still have algae issues, brown algae is taking over. I was hoping I was doing something wrong with the fuge.
I would trim the Chaeto periodically to remove the light green growth. That should fuel new growth.
If you've got that red-brown stuff with bubbles in it, that's not algae---it's a cyanobacteria sheet in the making. It thrives on the odd parts of the light spectrum: indirect light coming in from windows, a fading MH bulb (they never burn out)---all these things fuel cyano. Note that 'bacteria' part of the name. So regular algae-control methods can't get it. Best way I've found to tame it is the 3-day lights-out method. Plus curtain the windows near the tank during certain seasons of the year. I have a sneaky sunbeam that manages to reach my tank from the kitchen for a few months a year. I see it's starting up again. So I will be using this method myself. It throws its substance back into the water stream so your skimmer can have a go at it. If you have Mh lights, do the 4th day as actinic. Feed your fish as per normal.

Additional notes on cyano: it's what saved the planet's bacon after the Permian extinction; it grows on bad sunlight and releases oxygen, so it's nice our planet has it. It's a PITA in a marine tank. It starts as a brownish blush on the sand or brownish red film on a rock, and pretty soon it's thick and full of bubbles. Also known as red slime.
The red slime removers like Chemiclean are NOT for new tanks. It's Erythromycin, an antibiotic (read: bacteria-killer, do you see the problem?)
You just spent weeks cultivating bacteria in your sandbed and live rock and you're going to dose the tank with erythromycin? Nonononono...don't. Use the lights-out method. One caution: if you've got bad levels of cyano, all that dieoff happening that fast can push your skimmer hard. Watch your chemistry. Unfortunately, with Chemiclean, it includes part of your sandbed and rock bacteria, so the dieoff is even worse, and a young tank can't take that kind of roughness. I've used it. I wouldn't advise it.
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Sorry, should have been more specific... I wasn't expecting a response since I derailed the thread slightly.

I trim my Chaeto every 2-3 weeks. My problem is not Cyano. I have problems with Lobophora. It's taken over 2 out of the 4 rocks in my system, and working on it's third. The one rock (touching others that have it) has not shown signs of it yet. I have a small amount of hair algae also, but in comparison it's nothing.

Nitrate/Nitrite both sit at 0.