I usually have very specific reasons for things I do, and this applies to using hydrogen peroxide and NOT bleach (sodium hypochlorite). Why?
Bleach has many undesireable attributes, both during the 'bleaching' process and afterward.
1) During bleaching, the chlorine can cause substitution reactions with organic compounds, which are everywhere in living tissue. Some of the resulting compounds can be extremely toxic. Many of you may have heard of dioxins and PCB's, but furans are also a concern. These groups are particularly nasty, even in small quantities. I have some knowledge of these from my days in R&D.
http://www.ejnet.org/dioxin/">http://www.ejnet.org/dioxin/</a>
[IMG]http://www.pacelabs.com/assets/documents/dioxins-furans-literature/TEF.pdf">http://www.pacelabs.com/assets/documents/dioxins-furans-literature/TEF.pdf</a>
In short, I am not a fan of playing chlorine (halogen) chemistry in my tanks.
2) As to the byproducts of bleach after drying, it does form a blend of the two salts below.
(BTW-there are [B]thousands[/B] of salts in chemistry, besides the one we eat-sodium chloride).
[B]Reactions[/B]
Sodium hypochlorite reacts with metals gradually, such as zinc, to produce the metal oxide or hydroxide:
NaClO + Zn → ZnO + NaCl
It reacts with hydrochloric acid to release chlorine gas:
NaClO + 2 HCl → Cl2 + H2O + NaCl
It reacts with other acids, such as acetic acid, to release [IMG]http://en.wikipedia.org/wiki/Hypochlorous_acid"><span style="color: #0645ad">hypochlorous acid</span></a>:
NaClO + CH3COOH → HClO + CH3COONa
[B]It decomposes when heated or <u>evaporated</u> to form <u>sodium chlorate</u> and sodium chloride:[/B]
[B]3 NaClO → <u>NaClO3</u> + 2 NaCl[/B]
In [B]reaction with hydrogen peroxide it gives off molecular oxygen[/B]:
[B]NaClO + H2O2 → H2O + NaCl + O2↑[/B]
3) So, if you do use bleach, I strongly suggest that you add a little hydrogen peroxide after the bleaching and then rinsing several times, to drive the reaction to get NOTHING BUT salt (NaCl), as in the step above. Then rinse some more. Why?
4) *FYI- [B]sodium chlorate [/B](above)[B] is a nonselective herbicide[/B]. Guess what's in our corals? Yep, symbiotic algae, which are plants and can be killed very effectively by any residual sodium chlorate.
[IMG]http://en.wikipedia.org/wiki/Sodium_chlorate">http://en.wikipedia.org/wiki/Sodium_chlorate</a>
Also, FYI- there is NO hydrogen peroxide in common household bleach.
If you have a choice, why would you choose the one with greater potential hazard? Hydrogen peroxide is nothing but hydrogen and oxygen and breaks down into water and oxygen.
Hope this helps clear up any misunderstanding.