Re: UV Steril. & Photodegredation

> From: "M. Pearlscott" <pearlsco at u_washington.edu>
> I ponder getting a UV sterilizer for my 100gal, but have read some recent
> posts about them degrading the iron we add for our plants.  Does anyone
> know if you dose your tank daily with fertilizer, would the degredation
> the iron and other chelated elements by the UV ster. be enough to prevent
> the needed uptake by the plants?  Put in a more simple way:  How long
> would it take the UV ster. to break down the chelated elements in the
> water column (assuming usage of PMDD or similar fert. used to achieve
> levels suggested by Colin & Sears, flow rate through UV ster. is 3.5 tank
> volume/hr, and 100gal total tank volume. :) if you stopped dosing the
> tank.  50% gone in 24hrs?  More or Less?  Has anyone experimented with
> this on their tanks?

I tried to counter this effect by adding the drops in the morning
and not having the UV run until evening. Everything on my tank
runs from the central timer. It was really hard to tell if it worked
since I had big problems keeping iron levels up, even with the UV off.

Of course, this only works if you have a UV large enough to
reach a reasonable percentage of water in the time allotted.

Jon Wilson