[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: UV

Subject: RE UV wattage question
> If you have fish in the planted tank, do you think that 50%
> water
> changes weekly could be more stressful than lesser changes? 

No, it'll hurt algae more than plants and give an easy
estimation for adding nutrients back into your tank which if you
keep in good supply, will set the algae way back. Most folks do
not test all anal, all the time. Doing big water changes like
this helps "re set" your tank with far less testing each week. 
This means you'll be more likely to do it each week too.

This helps the plants to grow better.
Fish like water changes as far as I've ever seen.
Why would you think they do not(Generally here-not some specific
Killi from Ghana etc)? Happy plants equals happy fish which
equals happy owner. Nothing builds(say too much NO3) up by doing
this and all the dosing mistakes you've made all week long are
reduced and kept in check in this manner. A stable tank is good
and water changes helps this. Clean water and healthy plants.  
> Do you
> recommend 50% weekly changes as a temporary or a permanent
> measure?

Depends on your tank and tap and method. It's just one and it
works very well. Do you use CO2, Do you have high NO3 and PO4 in
the tap etc etc etc? It's not quite that simple:)
Doing a 50 % water change is easier than testing for 2-5 water
parameters and is better for most tanks....even in some cases
with all the NO3 and PO4's in the tap. The non CO2 tanks can go
months without water changes and do very well.
Some folks cannot do it for other reasons so they go longer or
some of us are just lazy and put it off:)We all fall into that
> Do you recommend a 15 watt UV for any size tank? 

Huh? No:)

> If so, why
> 15 watts
> rather than some other size? 

For a 120 gallon tank? Yes that's about a good size that will
kill whatever in about a day or so(GW, spores etc). 

> It seems that, since the
> lethality is a
> direct function of total effective exposure, which is a
> function of
> lamp intensity, and total exposure time, some cases require
> larger and
> others smaller lamps?  Of course, if the exposure rate is
> above the
> lethal minimum for algae, and all of the water makes it
> through the UV
> lamp during the period that it is turned ON, the lamp will be
> effective.  Based on the charts that I have seen for single
> pass
> lethality, 15 Watts is probably overkill for most tanks using
> a small
> water pump, say, a filter output.  This seems all the more
> true if the
> lamp is being left on for a day or two, so that all of the
> tank water
> cycles through the lamp many times, given that repeated
> exposures are
> lethal at somewhat lower intensities and durations than single
> pass
> exposures.

I'd rather have a silghtly higher/stronger light than a lesser
one. It's up to you but that's my take about it.

> The difference in price between 8, 15, and 30 watts is
> considerable. 
> If a person had only tanks smaller than 60 gallons, an 8 watt
> lamp
> might be more than adequate and less expensive to purchase and
> maintain.

Well yea......even a 4 or a 5watt. But as a temporay thing an 8
might be fine. If it goes through slower that's fine. Even if
there's less than 98-100% kill rate after some more time being
"on" this will make up for exceeding the flow rate etc. If it's
slower than the flow rating, it just kills better is all with a
single pass.

It's a very simple thing/concept. Many UV companies say what a
great thing they have etc yada yada...............
Some say two passes will be better(U shaped flow pattern) some
say a 3 inch dia tube is better etc...some have all these so
called helpful charts and other techinical info which really
seems to confuse rather than making it easier to buy one.......

Some folks seem to think that it is imperative that a 99-100%
kill rate is needed with each pass for these things to work.
It kills most of the stuff that passes through them within the
flow rating but it still kills some amount of suspended water
borne critters/algae that pass through it. It'll just longer to
see the effect. If you have overkill then it'll take less time
etc. Do you want to leave it on all the time etc. Personally, I
think that's a waste. Run it one day after the water change then
dump in your traces....that's about all anyone needs to run a UV
Some folks want it installed in line with their return so they
can simply flick a switch to turn it on then turn it on/off when
they add the traces. Some want to set it all up each time or on
a certain tank that "needs" it. I have just have one for myself
and use it on a bunch of different tanks when I feel the need to
which is not often.

Diatoms filter are nice for this too and do the trick. I use
both of these methods. But both are only a temporary thing run
once a week at most for a day or so.  
Tom Barr

> Scott

Do You Yahoo!?
Get personalized email addresses from Yahoo! Mail