Hi,

I just got back from my LFS and have an itemized price list of all the equipment I need for my new 55 - 70 gallon FOWLR tank.

A question - The owner/salesman insisted on an RO unit (I am on a city water system) and UV filter. I read "The Conscientious Marine Aquarist" and the author seemed to indicate that neither was a necessity.

Is there a general consensus on the value or need for RO and a UV filter? Or what are the determining factors?

I think you will find that most here use either an RO filter, or go and purchase water at the local stre (not a good idea for a tank your size). The amount of phosphates and the like in city water will cause algae blooms amoung other things. As for UV filters, many here use them, but not all. i for one do not have one, however I am in the market for one at the time.

Welcome and hope that helps!

if i had to choose between the two i would pick RO.
unless you know exactly what's in your water, you want to filter it.. your LFS is giving good advice..

as for the UV filter, i agree they are of great benefit, that said they are best used in tanks with a medium to high bioload and/or have a need for extra filtering, polishing, or parasite control

While the quality of your city water should always be fine for drinking it does vary. You could use it for a while and be OK and then some parameter changes and it knocks your tank out of balance. (I worked in the lab for our Public Utilities for several years.) I'd go with the RO for sure.

It seems that most reefers use and RO unit. Use of a UV is split. I use RO and like Wildeone, I too am looking for a good UV sterilizer. Any suggestion anyone? Tank is 120 gallon turning over about 1000 - 1200 gph through sump.

I personally use RO/DI filtered water in my aquarium. A year ago I never had one and used tap water. What a battle fighting off Red Slime Algae. As for a UV Filter I have one, my thoughts on it are like a condom. I rather have and not need it... then need it and not have one! :-)

Get the RO unit, save yourself some headache!

Can i throw in a "Ditto" here? When I had a bunch of guppies/mollies (fry for the seahorses) I used treated tapwater. Then one time there was excessive rain on the other side of town and the city treated the water more than usual to fight contaminents.... lost most of the fish.

I never trusted city water again... I don't let anyone else have control over any aspect of my obsession but me.