Question
We have several ponds- have been using the water treatment known as "Back-up" but can't find a source for it anymore.  I used to buy it on-line- but now it seems to have vanished.  Do you know of an adequate replacement for this wonderful product.  My wife has been asking about it for a year now.  We also have a river otter tank that we need to treat- currently has too much algae and must dump it every three weeks- putting fish in it does not work- the otters go crazy eating them- so we must treat the water organically- we don't wish to use chemicals and hurt the otters.  Thanks for your wonderful input- Brian

Answer
I have not heard of that product.  I tried to search for it but, unfortunately, the words "back-up" are just too common even with pond water treatment added to it.  Do you know who made it?  Do you know what it was (good bacteria, enzymes, chemicals, what?).

You have river otters?  Do you work at a zoo?  I've never heard of any one having them as pets.  They are sure fun animals to watch though.

As far as an all natural water treatment that contains good bacteria and enzymes, I suggest BZT.  I use it in all my aquariums and ponds.  It literally dissolves away animal wastes.  It can help with algae too.  Here's their web site:
http://www.united-tech.com/m-aq-toc.html
http://www.united-tech.com/aq-summary-zooponds.html
It seems expensive but that $76 lasts me a year for 2 ponds and 4 aquariums. You can also get a $35 or so smaller amount called the Ponder's Special if you call them and tell them I sent you.  [I don't get any commission or reward for referrals; I pay full price when I buy it; I really swear by this stuff.]

Good luck!  I'd love to see photos of your otter tank!