Allright, I know that all of us at one point or another have battled nuisance algae. namely cyno.
I decided to do some homework and see what I could find to pass along to you guys. I actually learned quite a bit about this.
The thing that I found out that is the biggest help in eliminating these nuisance diatoms was to actually promote the controlled population of diatoms!!! BEAR WITH ME!!!

Most aquarist intro to diatoms is as an unsightly reddish brown coating of their sand and rocks in the first few weeks of a new tank. at that point, most of us decide that diatoms are a bad thing. and from there on the battle began. When diatoms are out of balance (like a bloom) they dont do anyone much good. but when diatom populations are in a stable balance with other proceses in your tank, they are very good for the whole system.
Good thing:
Diatoms compete with blue green algae for resources
Diatoms are much easier to remove from glass and acrylic and less unsightly than blue green algae.
diatoms are part of PLANKTON and just like planton products that you can buy, they provide a healthy natural food for filter feeders.
Diatoms consume nitrates and phosphates from the water column and fix them into their tissue where it can be filtered out of your system via your protein skimmer.
Diatoms on your sand are some of the best possible food for your cleanup crew and are likely to contribute to their longevity and increased health.

I am not going to go into how to dose sodium silicate, if you want to know PM me and I will tell you how to step by step

A couple other pointers
In any closed environment with animal life and light you are going to get plant life. Our tanks are not exception. so the only choice is whether you get the plant life you like, like corraline algae, macro algae, sea grasses, mangroves, or corals. or you get the plant life you dont like such as hair algae and cyno.
Every bit of ammonia, nitrate, phosphate, toxin, heavy metal, and carbon dioxide consumed or bioaccumulated by plant life you like is one less bit to feed the plant life you do not want or to adversly affect other life you like.

As long as the speed of phosphate removal is greater than the speed of production, all nuisance algae will eventually have to die off, as the phosphates are removed from the system.

the 2 things that confuse aquarists are that:
1. the resulting die off of algae takes time
2. zero test levels from the water column is not the same as zero production, or uptake, of PO4

The aquarist needs to enable the system to dump phosphates BEFORE they can get used by algae, if 5ppm of PO4 is produced, and 5ppm uptaken by algae, one will still test a level of zero, as this only measured excess that builds up in the water column.

The easiest way to eliminate one major source is via RODI water
the second, is to use a phosphate sponge, like phosguard, or rowaphos.

Since algae require phosphates to grow and thrive, PO4 removal is not only the true root CURE its also the least complicated treatment around, for dealing with nuisance algae.

Clean up crews (especially snails) merely recycle the algae, releasing the PO4 in their poop, to begin the process anew.

combine that with what most of us allready know:

increased flow in the tank
a good skimmer
not over feeding

and that nuisance algae is a lot easier to get a hold on than you think.

sorry for the long read. thanks for tagging along!!!

GREG

Thanks for that post Greg. I never thought of snails recycling the PO4 but that makes sense.

Out of curiosity, have you ever heard of someone injecting CO2 into a container filled with macroalgae to promote its growth and out compete the nuisance algae? I see this done all the time with planted freshwater tanks, but always wondered if anyone has tried it with macroalgae.

I have not but it would be neat to try, might have to give that a go and see what happens. I will let you know.

Very nicely done. Lots of good info, and in an easily understandable form. I'd like to add that if the algae already has a hold, and is taking up PO4 as fast as it's produced (or introduced, if you will), manual removal of the algae (pulling it out) after you're running some form of phosphate removal is especially beneficial. Reducing the biomass of the algae allows the phosban or what have you to absorb more of the PO4 from the system.

Phurst, your correct sir thank you for adding that!!!!

Thanks, I've, uh, been a few rounds with the algae monster in the past....
:D

Nice post! Very informative :)

A couple other pointers
In any closed environment with animal life and light you are going to get plant life. Our tanks are not exception. so the only choice is whether you get the plant life you like, like corraline algae, macro algae, sea grasses, mangroves, or corals. or you get the plant life you dont like such as hair algae and cyno.

Just wanted to point out that corals are not plants, they are in the Animal Kingdom.

yes you are correct sir. thanks for pointing that out.

What are your thoughts on turning the lights out for a couple days when first introducing GFO. I think it could give the upper hand to the GFO so that it can uptake the PO4 before the algae can?

I have heard of people doing that with positive results.

Beautifully put graphixx.
You nailed it.

As for Co2 injected planted systems. I had a 55 packed with macro algae. Nitrate consumption alone was my limited factor. I could not dose enough.

CAUTION.

(If your new to saltwater DO NOT TRY THIS!!!!! )

I was dosing an entire 250mL bottle of seachem’s Nitrogen every five days and still could not detect No3. Co2 was not needed. I tried it early on with a yeast reactor but I got tired of unhooking it every night.