uv and flow rates

[gypsy3]

hi...i'm getting a 36w pondmaster uv. i understand the slower the flow rate, the better the uv works. will the flow rate from an aqua one 2400 be too high to operate with the uv? if so, can someone advise what would be compatible to run the steriliser with.what would be the ideal flow rate to run thru the uv be? its a 6x2 tank

[tzwms]

The directions with the Pondmaster UV will state the max flowrate. If it is less than your filter, you can either do a bypass around the UV for the extra flow or just throttle down on the filter. Either of these requires that you have some means of determining what the flow is through the UV. If the flow exceeds that recommended for the UV, its effectivity will be greatly reduced.

HTH

[gypsy3]

that's what i'm wanting to find out. the lph on the 2400 is supposedly just that, 2400 litres p/h, although no doubt it's a lot less than that. what in people's experiences would the real flow from that filter be and if it's too high, what would be a good filter to maximise the uv capability?

[tzwms]

We are pretty much back where we started. I can't say anything about what the actual output of the pump will be; too may variables. You would almost have to take some container that you knew the volume of and with similar tubing diameters and lengths see how long it takes to empty or fill. But in the end, you are still going to have to look at the packaging for the UV lamp and see what the recommended maximum flow is.

HTH

[tzwms]

If this is what you are getting, the stated maximum pump size is 36000L/H.


http://www.thereefshop.com.au/index.php?main_page=product_info&cPath=30&products_id=302&zenid=97a61c1c21793111c989eb263871e3b6

If this isn't it, what exactly are you buying? I'll hazard a guess, site unseen, that your pump will not bee too large.

[ILLUSN]

output of the 2400 is ~1190-1310L/hr depending on hose length

[tzwms]

I guess we will have to hear from Gypsy3 on whether I identified the correct UV unit, but it looks like there is no problem with regard to flow.

:)

[ILLUSN]

it will work fine, i use a 36w but i have it "T'd" in so as 1/2 of the flow goes through the setilizer, the other 1/2 strait to the tank.

a 36w is only really good at a flowrate of about 720-900l/h or less if you want to kill most things.

[tzwms]

Hmmm! I wonder why the manufacturer says max pump size of 36000l/h then. Even the data on the 20W was double what you have stated. :?

[Merrilyn]

We've come across this before tzwms. Flow rate is measured without any media in the filter, and without taking into account head height. I'm pretty sure all the manufacturers measure it that way.

Once the filter is filled with media, the flow rate drops by around 50% and drops even further as the filter pads become dirty.

A UV can either be rated as a clarifier or sterilizer. A clarifier will work at a higher flow rate, because all you're doing is killing the algae spores in the water. If you want to kill the bacteria and other nasties in the tank water, then you need more exposure time to the UV globe. In other words, a slower flow rate.

[gypsy3]

yep tzwms, that's the one. just one more question tho. so does that mean that if the flow rate was only say 3-400, would the uv be even more effective, that is, the slower the rate the better it works?

[taksan]

Slower the rate the better it works

[gypsy3]

cool....so i might just be better off buying a cheap canister filter , load it up with media and have it run exclusively with the uv...say a 1000L, with media and travelling up about 1.5 metres, that should result in a pretty slow rate shouldn't it? by the way, thanks to you all for your help...and patience :)

[gypsy3]

hi all ...this may sound like a silly question, but if the slower the flow rate the more efficient the uv system, why wouldn't you run it at say 1-200 l/h to get an even better performance, or is that TOO low?

[tzwms]

You need to match the flow against the size of the tank. Too slow and the organisms can reproduce faster than you are killing them. Thus if you are trying to take care of an algea bloom, if the flow is too slow, the tank never clears up.

HTH,
:)

[gypsy3]

ok, thanks for that.so what do people think would be an effective flow rate for a 700 litre tank? i'm hooking mine up to a (supposedly) 2000l powerhead with sponge filter that is dedicated to the uv only. i figure that once it goes thru the intake, travels down about a metre to the uv, then back up about 1.5 metres, the flow rate will be significantly reduced. Any opinions?

[ILLUSN]

if your flowrate is really at the 2000L mark you'll need a 72w uv or bigger to STERILIZE the water.

on a 700L tank i'd go for something like 1000-1200L/hour and a 36w or 55w unit

[mich]

sorry to jump in your thread :shock:

just wanna ask if 1x eheim 2217 flow rate would be about 1000/1200 lh
after substrate and head height of approx 1.5 ? any clues

thanks heaps

[ILLUSN]

at that height the MAX output of a 2217 will be 550-600L/hour. at 1m height the best i got was around 660L/hour