While researching an issue I was having, I happened to come across this article - http://www.americanaquariumproducts....Potential.html
- The Rexox Potential (ORP) in Aquariums & Ponds, How it relates to Good Aquatic Health: Effect of water changes, DOC, UV Sterilization, mineralization on a healthy Redox Balance, byt Carl Strohmeyer.
If this article is true, in whole or in part, then Redox (even if it is tricky to measure), is a a very significant water parameter which I'd basically been ignoring at my expense and peril! I thought Redox was mostly a concern for reef aquariums, but supposedly it happens to greatly underpin the very health and success of our freshwater systems and explains a great many things which other water parameters do not.
It seems the author has its detractors on this, such as Tom Barr, but I wasn't sure if that was a disagreement over just certain aspects of the argument or the entirety of it. Tom seems more concerned with the Redox of the substrate for plant health, at the peril of misquoting him based upon having seen some comments of his thus far. He has one or more articles on his report so I should perhaps really get around to subscribing to that now, but which I haven't in any case done so for.
The author has in any case clearly put a great deal of thought and attention into this matter and seems relatively convincing, though there are certain points which I'm also questioning. Then I also found this article which differs somewhat in its recommendations - http://www.koiclay.com/page6.htm
Apparently Redox is a more or less clear indicator of the health of your system and the amount of organic pollution in it with a range between 250 and 400 being desirable. And Redox can be raised by many means including: oxygenation via aeration/flow, removing organic matter, lower stocking levels, water changes, biofiltration?, activated carbon, adding 'fresh' calcium and magnesium, ozone, UV Sterilizers. I have to assume that healthy plants raise Redox levels as well though. Nevertheless, is Redox as discussed in the first article supposedly the key reason why you'd want to have regular water changes and low fish stocking levels, regardless of how low your nitrates are. But are plants a better biofilter than bacteria, as they'll raise Redox more than bacteria do?
And thus, if you have low Redox you'll be more likely to have problems with both algae and fish diseases? Carl's article sounds rather different than the suggestions put forth by Diana Walstad, who seemed perfectly fine with having high DOC, although it might explain why she also suggests maintaining low stocking levels. But then there is also the first article's discussion over Redox balance, which suggests that lower Redox levels than 300 aren't bad actually, but I'll still need to get my head around some of that and reread things through.
I did happen to order some wonder shells from Amazon.com now to try out, although it also now seems that a bag of aragonite or crushed dolomite added to the filter would have also worked. But as I'm not trying to maintain hard water I might need to stick a decent amount of peat into the filter to buffer the alkalinity of those?
And apparently it seems that the use of ozone or a UV sterilizer would greatly help the help of my/our systems by raising the Redox, (so long as controlled properly in the case of ozone to not raise the ORP too high). It sounds as if UV sterilizers are much easier and safer to use though, and help maintain very clear colorless water by also oxidizing whatever DOC's/tannins/etc pass through them.
Please advise! And thanks in advance!