GHA, Hydrogen Peroxide, and Chaeto

[Klyph]

So I continue to battle green hair algae in my 150 gallon tank. I shut down my refugium 6 months or so ago, while I’ve been fighting the GHA, since my primary weapon was hydrogen peroxide and it was definitely killing off my chaeto.

Well over the past 6 months I’ve been spot treating the GHA with hydrogen peroxide. About once a week, I turn off all pumps and skimmer, and spot treat with about 40ml of 12% peroxide. After about an hour, I turned the pumps back on. Theory being that the peroxide becomes inert “eventually” (let me come back to that)

I declared success about a month ago, as I couldn’t find any little tufts of GHA, so I have reintroduced my refugium with very clean and very healthy chaeto. Haven’t added any peroxide since. My refugium uses an AO prime fuge light at 80% for 16 hours a day, and has a pump spinning the ball of chaeto.

Here’s the problem, although still alive, it’s a little weaker and most of the outer edges are turning gray. It looks just like it did when I started adding peroxide earlier this year (even though I haven’t added any in weeks). And now my GHA is coming back again.

My primary question, is peroxide truly inert, or is there a chance it leaves some residual that negatively impacts chaeto? Is it safe to spot treat the main tank with pumps off for an hour, or will the residual peroxide make the chaeto even worse?

Btw my parameters are all fine
Salinity 1.026
Ph 8.1
Temp 78
Dkh 9.5
calcium 450
Mg 1450
Phosphate 0.09 (a little high at the moment. Usually in the 0.03 range)
Nitrate 3
Last 32g water change last week
Triton icp test- all others elements in normal range

I’ll get the following advice if I don’t share, so want to note that I already run a skimmer, carbon, and now my fuge is back online. I have 3 tangs, four tuxedo urchin and other cuc. I do regular water changes.

So with all that said, My primary question/concern is with my balance of fighting GHA in the display, while also trying to re-establish my chaeto in the fuge. That balance of using peroxide in the tank, while also supplementing things like ChaetoGrow for iron and iodine is tricky, you know.

I’m actually considering just giving up on the fuge, and stick with weekly spot treating peroxide in the display, basically forever.
Thoughts?

 

[Reefahholic]

I’d do some water changes and get the H2O2 out. It dropped my pH for weeks, but every system is different.

Just get it out, run some carbon, and start the fuge again to outcompete the GHA.

 

[Subsea]

Nitrate is low in your tank. I suggest adding a nitrogen source. I use ammonia.

With respect to hydrogen peroxide used in tank, I use a toothbrush to spot treat. Also, peroxide is very effective in eradicating Aptasia. I see little need to worry about decaying organics from GHA. Use granulated activated carbon to remove DOC.

 

[Subsea]

“Well over the past 6 months I’ve been spot treating the GHA with hydrogen peroxide. About once a week, I turn off all pumps and skimmer, and spot treat with about 40ml of 12% peroxide. After about an hour, I turned the pumps back on. Theory being that the peroxide becomes inert “eventually” (let me come back to that)”

@Klyph,
Curious as to how your micro inverts like pods & mini starfish handled that much peroxide.

Peroxide in not inert, it is a powerful oxidizer. It will deplete itself as it breaks down with light.

 

[Dburr1014]

I’d do some water changes and get the H2O2 out. It dropped my pH for weeks, but every system is different.

Just get it out, run some carbon, and start the fuge again to outcompete the GHA.

What do you mean "get it out"?
H2O2 is water, once the 2nd O molecule is gone so is the oxidizer. It's just water again. Unless the OP used a bottle that had something else in it.

 

[Megaloptera]

What do you mean "get it out"?
H2O2 is water, once the 2nd O molecule is gone so is the oxidizer. It's just water again. Unless the OP used a bottle that had something else in it.

Agreed, H2O2 spontaneously decomposes when exposed UV light. That's why it's sold in dark bottles. Within 24 hours all H2O2 has turned into H2O and O2.

 

[Klyph]

“Well over the past 6 months I’ve been spot treating the GHA with hydrogen peroxide. About once a week, I turn off all pumps and skimmer, and spot treat with about 40ml of 12% peroxide. After about an hour, I turned the pumps back on. Theory being that the peroxide becomes inert “eventually” (let me come back to that)”

@Klyph,
Curious as to how your micro inverts like pods & mini starfish handled that much peroxide.

Peroxide in not inert, it is a powerful oxidizer. It will deplete itself as it breaks down with light.

I still have a few mini starfish, but I can’t keep a pod colony. I’ve seeded the tank with algae barn pods, but never see any. I’ve assumed that the result of the peroxide. That is another negative consequence of peroxide.