Adding to the UV discussion..

["Adam Shaw" <adams1 at comcen_com.au>]

Just adding to the UV discussion...

I run a Rainbow Lifegard 8w UV module on my 70g planted discus tank.
Recently I have had to move my tank due to a canister filter leak which
lead to 100L of water being drained onto the carpet overnight (but we
won't go there...). As such, since I was running my UV from the outlet
of the canister, the sterilizer has been offline for 2 weeks now. The
water clarity has gone down somewhat (I have to say, the UV module does
make a lovely difference to the crystal clarity). It is not putrid but
it is noticeably less clear than with the UV module working.

Some time ago when the UV module was running, I managed to get an Ich
infestation. Whilst noting that UV can be a great safeguard, I'd advise
against the idea that UV is a miraculous disease cure. When looking at
the amount of UV needed to kill some water-borne parasites, and
comparing them with the usual sorts of sterilizer specifications, in a
lot of cases the UV sterilizers available to the aquarist do not suffice
anyway. Noted however, discus are notorious little buggers for that kind
of thing, and the ich parasite itself is a damned hardy little critter.

However, I never regret buying my module - the clarity and peace of mind
it has provided for what disease prevention capabilities it possibly
has, has been invaluable. I wouldn't have discus without them.

As far as nutrients and iron photo-reduction etc etc..... *shrugs* who
knows. I use the seachem range at the moment (switching soon to generic
stuff from a hydroponics store because the seachem range are so damned
expensive here in Oz), and only really when I do water changes with
Seachem Flourish Iron. I test weekly usually for iron and do not notice
substantial changes - only small amounts which I attribute to be being
used by the plants (my tank is fairly heavily planted). So... Personally
I'm not too worried about it.

Cheers,

Adam Shaw
Australia