UV Sterilizer Sizing, best practice.

[Reeflux]

If I size the UV based on the needs of my tanks flow rate, but in doing so, have to use the smaller 25w model, (which is rated for tanks up to 130g) and my tanks 150g + 30g sump.... should I not even install it?

Brs videos seem to reiterate either go big or don't use it at all.

Basically, I'll be 30 or 40 gallons under the pentair guide....but I can't go up in flow. I don't have the flow coming out of the dt to go up to the next size. I'm running 1 inch lines. I'll get a max out of the tank of 930gph on the siphon + the open channel. Going up in size just doesn't work.

So should I spend $400 on something possibly flawed in the first place. Or am I getting $400 worth out of it even if I'm a bit undersized.

 

[DaddyFish]

My head is spinning trying to read your post numbers!

You have 180 gallons of working volume, correct?
And you're looking at running a 25 watt UV??? No way, no how! WAY undersized.

You can run a larger UV at it's minimum recommended flow rate without much problem. Heating of the water column will be about your only concern. You will probably want to cycle the UV On/Off, running it something like 12-hour intervals, and that will shorten the lamp life expectancy quite a bit. But that sure beats plumbing in a UV that's going to be way undersized the first time your water gets cloudy, or the lamp is 8-months old.

 

[Reeflux]

Yea I guess I do. Minus volume loss of maybe 80 lbs of rock.

It has its own dedicated return.

The suggested flow rate on the 25w for algae is 472 gph. I'm pulling on a full siphon 930 maybe, then add the open channel, whatever that is.

You go up in size and I'm way out of bounds.

So I'll have the u.v. return set on 472 gph and I'll consume the rest with the main return.

I didn't think shooting for 10x turnover rate through the sump would be needed. I thought that was overkill.

 

[DaddyFish]

Yea I guess I do. Minus volume loss of maybe 80 lbs of rock.

It has its own dedicated return.

The suggested flow rate on the 25w for algae is 472 gph. I'm pulling on a full siphon 930 maybe, then add the open channel, whatever that is.

You go up in size and I'm way out of bounds.

So I'll have the u.v. return set on 472 gph and I'll consume the rest with the main return.

I didn't think shooting for 10x turnover rate through the sump would be needed. I thought that was overkill.

You don't have to have 10x turnover rate for algae. 8-10x is better, but 4-6x will get it done.
For parasites 2-3x will get it done.

 

[Reeflux]

You don't have to have 10x turnover rate for algae. 8-10x is better, but 4-6x will get it done.
For parasites 2-3x will get it done.

Yea, no I mean with my drains through the whole system.

In order to be sized right for this my only option is to replumb it in a bigger diameter.

So let's say I'm running a 25w on 160 gallons, when it's rated for 130g. (I'm still hitting it's required flow rate perfectly). I'm just undersized on the gallons recomendations. You think that's bad?

 

[DaddyFish]

Yea, no I mean with my drains through the whole system.

In order to be sized right for this my only option is to replumb it in a bigger diameter.

So let's say I'm running a 25w on 160 gallons, when it's rated for 130g. (I'm still hitting it's required flow rate perfectly). I'm just undersized on the gallons recomendations. You think that's bad?

As long as you do not exceed the maximum recommended flow rate, it's doing some good. Much depends on water quality/clarity and age of the bulb. Keep in mind that the maximum recommended flow rates are for optimum conditions where the water is clear and the bulb is new.