Overdosed hydrogen peroxide. Help!

Humble_Reefer · Jun 21, 2020

I overdosed my tank with H202. For some stupid reason I did 30 ml into a 70 gal system, so over 4x the recommended 1 ml per 10 gal for dosing. About 3-5 minutes after dosing to the sump, I realized my mistake and cut the return pump. Then I did a 20 gal water change, 10 from the sump, 10 from the display. I was low on RODI water so I am currently making more. Not sure if it would help, but I forgot to take my activated carbon out of the sump. Im just trying to figure out how worried should I be? LFS is closed. Do I call my buddies for RODI?

Any advice is appreciated.

30-45 mins in, some corals are retracted and closed, but some look fine, so no different than a usual waterchange.

MERKEY · Jun 21, 2020

Its so hard to say how your tank will react...I would get more RODI and do more water changes.

A olus side is algea will die...

What all do you have in your tank?

Retro Reefer · Jun 21, 2020

With the quick water change you may be ok, I think water changes are your best possible option I would do another asap however the hydrogen peroxide will dissipate quickly.

Humble_Reefer · Jun 21, 2020

MERKEY said:
Its so hard to say how your tank will react...I would get more RODI and do more water changes.

A olus side is algea will die...

What all do you have in your tank?

It's my frag tank, so a bunch of corals, many that I don't have in my display, and 2 fish (coris wrasse and blenny, and some CUC.

Humble_Reefer · Jun 21, 2020

Retro Reefer said:
With the quick water change you may be ok, I think water changes are your best possible option I would do another asap however the hydrogen peroxide will dissipate quickly.

Think more activated carbon would help too?

Retro Reefer · Jun 21, 2020

Humble_Reefer said:
Think more activated carbon would help too?

Not a chemist but I don't think carbon will help at all.. depending on the corals you're probably going to be fine, I have seen lots of H2O2 overdoses here on the forum and it typically does little or no damage.

Riphter · Jun 21, 2020

Carbon won’t help. Most corals survive a peroxide dip. Just change some water and get some bacteria.

Riphter · Jun 21, 2020

Also if you have a refugium.. that algae is probably a goner.

Jamesrup0411 · Jun 21, 2020

If you have a display why don’t you move some coral out of your frag?

JoshH · Jun 21, 2020

Retro Reefer said:
Not a chemist but I don't think carbon will help at all.. depending on the corals you're probably going to be fine, I have seen lots of H2O2 overdoses here on the forum and it typically does little or no damage.

I agree, Used more than 1ml a gallon multiple times with no real ill effect...

If you're concerned toss an air stone in the tank and up the flow it will dissipate the H2O2 much quicker. But personally I'd just keep an eye on things. Reacting too quickly and doing multiple WC's could actually do more harm than good...

If you have a Fuge maybe take it offline for a couple hours or overnight, once again if you're really concerned

Riphter · Jun 21, 2020

H2O2 creates O2 as it reacts. It really only stays active for less then a day. The byproduct of peroxide is hydrogen, H2O and O2. The ph can drop when dosing peroxide. Your light will break it down pretty quick. Organic matter will also break it down. People routinely use peroxide as a coral dip.

vetteguy53081 · Jun 21, 2020

Water change is answer as peroxide is mainly water and should not have an adverse effect

Casket_Case · Jun 21, 2020

H202 typically breaks down to O and H20 so it should be okay... if not Oxygen and Water you’ll get some hydrogen. Not sure how you’d take care of hydrogen as I haven’t dove into the chemistry side of reef tanks...

Anchor · Jun 21, 2020

Wow something i have experience with chemically..

Zoas will close up and some LPS.. I dont have experience using it around SPS.. H2o2 is very reactive and will disipate within 4 or 5 hours.. A water change is OK but by the time you do it, most of the peroxide is going to be used up.. It can kill the zoanthalae in your zoas if too heavily over-dosed. but the amount you used should be fine..

Peroxide is going to react mostly with chlorophyll and some colored plant pigments in your corals.. but again.. you didnt really use much.

I have done 200 ml in a 75+sump system and other than stuff closing up and Halimeda dying off. No effects otherwise.

Anchor · Jun 21, 2020

Frigus Reef said:
H202 typically breaks down to O and H20 so it should be okay... if not Oxygen and Water you’ll get some hydrogen. Not sure how you’d take care of hydrogen as I haven’t dove into the chemistry side of reef tanks...

Hydrogen will disipate very fast.. if it comes off as pure H2.. but likely not going to do anything but disappear. too little produced to have any effect. will usually react with what is in the water causing a very small drop in pH if anything..

Anchor · Jun 21, 2020

My experience has been that Zoas will close up with as little as .3 ml per gall on of 3% peroxide.. so it dont take much for them to react.. Usually open back up within 15 minutes.

Doctorgori · Jun 21, 2020

I can sympathize: I JUST posted something similar; I smoked an entire tank of about 1K in SPS frags et. They started had already started encrusting. I’m thinking Peroxide is most damaging when you dose alot at once or over a long period of time (I did both). Again; My SPS frags were smoked, all of them. most of the LPS and fish made it OK. Good luck

hllb · Jun 21, 2020

What percentage of h202? I use 35% which is a far cry from the typical 3%. If you used 3% you’ll be fine.

Humble_Reefer · Jun 22, 2020

Thanks for all the help everyone. Really appreciate the input. I ended up not doing any more than the initial 20 gallon waterchange as other threads on the topic mentioned that the H2O2 will evaporate within an hour or so, and it would have been hours before I got back with any RODI from my buddies.

I did put in an airstone as someone suggested this might increase the evaporation. At lights out last night everything looked fine actually, including sps, acros, and a range of lps and softies. Just the zoas looked mad. I'll update the thread with total casualties just in case anyone following now or poor suckers in the same boat are looking in the future. To clarify, it was 30 ml of 3% H2O2. While 1 ml per 10 gallon appeared to be the recommended dose to me from online instructions (so 7 ml for my 70 g frag tank), it seems others have purposely dosed more with no ill effects. So fingers crossed everything is fine when the lights come on!