UV Sterilizer with Canister Filter?

[MamaP]

Hi, All.

I'm looking to add a 40 watt UV sterilizer inline between my Fluval FX4 canister filter and the output head. My question is about the flow. The filter says it has an output of 700gph, but the max flow for protozoan control is 262gph.

Can the inline work, or do I need to come up with a way to make a closed-loop somehow? What's the best way to ensure I'm treating the most water effectively?

I appreciate any advice!

 

[SaltwaterGuruNeeded]

I'm not an expert but maybe you could make a smaller line off of the fx4 with some type of adapter so that most of the flow would go straight into the water and you would get a lower flow through the uv resulting in the correct gph for the protozoa. So you have a main line and then a split into the uv. The uv tube would be smaller.

 

[MamaP]

I'm not an expert but maybe you could make a smaller line off of the fx4 with some type of adapter so that most of the flow would go straight into the water and you would get a lower flow through the uv resulting in the correct gph for the protozoa. So you have a main line and then a split into the uv. The uv tube would be smaller.

I thought about that. Maybe a splitter of some sort? I just want to be sure I'm treating as much water as possible. I'm tired of ich outbreaks!

 

[SaltwaterGuruNeeded]

I thought about that. Maybe a splitter of some sort? I just want to be sure I'm treating as much water as possible. I'm tired of ich outbreaks!

Going through an outbreak myself. Try to get a quarantine going. That's what I'm trying to do. The sterilizer will help mitigate the ich but I've heard it won't kill it. It will just stop it from reproducing.

 

[MamaP]

Going through an outbreak myself. Try to get a quarantine going. That's what I'm trying to do.

Yeah, they've all been quarantined and I've gone fallow twice in 2 years, but somehow it keeps getting in. The only thing I can think of is that maybe it came in on a macroalgae or snail, even though I dipped and scrubbed everything. Grrrr....

 

[SaltwaterGuruNeeded]

Yeah, they've all been quarantined and I've gone fallow twice in 2 years, but somehow it keeps getting in. The only thing I can think of is that maybe it came in on a macroalgae or snail, even though I dipped and scrubbed everything. Grrrr....

Did you fallow for the full 76 days? This is getting off topic, I suggest you make a new post about your ich getting "into" your tank. But up to you

 

[Nate Chalk]

I ran a jebao off my fx6 it helped rid of some cyano. Uv is about flow rates and the size look up a chart they are available likely

 

[Mywifeisgunnakillme]

Hi, All.

I'm looking to add a 40 watt UV sterilizer inline between my Fluval FX4 canister filter and the output head. My question is about the flow. The filter says it has an output of 700gph, but the max flow for protozoan control is 262gph.

Can the inline work, or do I need to come up with a way to make a closed-loop somehow? What's the best way to ensure I'm treating the most water effectively?

I appreciate any advice!

Add a ball valve and reduce flow. Canister filter wont care and UV will kill ich then.

 

[MamaP]

Did you fallow for the full 76 days? This is getting off topic, I suggest you make a new post about your ich getting "into" your tank. But up to you

Yes.

 

[MamaP]

Add a ball valve and reduce flow. Canister filter wont care and UV will kill ich then.

It won't kill the canister?

 

[Mywifeisgunnakillme]

It won't kill the canister?

Put the valve on the outflow. Most pumps are okay with restricted flow on the out flow side. Not much different than the filter being full of crap, so i presume its design to handle some back pressure.

 

[Mywifeisgunnakillme]

People seem to do it... it is harder on the pump. A valve and splitter would be an easy alternativr.

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[DaddyFish]

Put the valve on the outflow. Most pumps are okay with restricted flow on the out flow side. Not much different than the filter being full of crap, so i presume its design to handle some back pressure.

Sorry, but this is bad advice. Never, ever put a restriction on the outflow of a canister filter. The canister seal is designed to withstand max pressure-X based on the rated maximum head pressure. If you restrict the canister output you can easily reach or exceed that pressure level.

Always place the restriction on the intake side of the canister system.

 

[DaddyFish]

@MamaP What size tank? I will do my best to advise you. I've done many canister systems with integrated UV.

Adding a couple pics of one of my canister systems...

Odd, but I don't have a most recent picture of this system. I've since added a DC return pump to boost the flow from the canister and to give me the ability to tweak the system flow through the UV. Additional pump was added on a stand near the blue circled area.

That's an Oase Biomaster Thermo 850 with a Coralife Turbo Twist 12x (32-watt) UV. 90-gal tank.

 

[Mywifeisgunnakillme]

Sorry, but this is bad advice. Never, ever put a restriction on the outflow of a canister filter. The canister seal is designed to withstand max pressure-X based on the rated maximum head pressure. If you restrict the canister output you can easily reach or exceed that pressure level.

Always place the restriction on the intake side of the canister system.

I doubt that beefy canister would pop or leak even if you restricted flow 100%, but the intake side is fine if the pump does not mind. The review i read said people reduce flow on the outflow side. that said, daddyfish, has logic to what he's saying. I just think restricting either side is not ideal for the pump, but either would work....

I would try both and see if seems over burdened either way.

Better is splitter with a valve on the side that goes to the UV.... But if you're in a pinch and fish need help ASAP then i'd do just about anything.

 

[DaddyFish]

It's been my experience that by the time you buy all the plumbing parts (quality gate valve etc.) and make a reliable bypass setup, you'll wish you had just upsized the UV to match the flow rate of the canister.

It's also very important to realize that the rated flow rate of pumps, especially those on canister filters, is typically WAY overstated. Reality is closer to 65% at a minimal head height on a short tank, and can easily drop to the 40-50% range at 1-meter head height. So don't do the math using the manufacturer's rated gph on the filter, cut that in half and you will be very close to the typical canister under the tank with moderately dirty filter media flow rates.

With almost all canister filters using the same, classic impeller pump designs, my little "cheat" is 1-watt UV per watt of canister pump. So an FX4 with a 30-watt pump, should have at least a 30-watt UV in the typical setup.

 

[Mywifeisgunnakillme]

It's been my experience that by the time you buy all the plumbing parts (quality gate valve etc.) and make a reliable bypass setup, you'll wish you had just upsized the UV to match the flow rate of the canister.

What size tank is this?

I have a 50 gallon tank with a 50 watt pentair and bought 120 watt for 200 gallon. The latter is about 600GPH for ich--but this is a like 5 foot long UV. The former i just did a splitter on my return to get about 240 GPH and that works, haven't touched it since it was set up.

Great point about the stated GPH and the actual flow....

Measure the flow into a bucket and time it for a minute. Then do the math to figure out where the canister stands as to GPH without restriction at the height of the tank. Then go from there.

If it was me, and my fish were sick, i'd restrict that flow (either side--whatever seemed to work better) and get UV going ASAP... but that's just me prioritizing fish over gear. My bet is that beefy canister would be fine with it for a long while. I had a magnum canister (very similar) and it would clog up and run at low flow for weeks.... It didn't care and outlasted my need for it, as in years, through two fresh water tanks (even dirty butt piranha) and then as a water polisher on a saltwater tank...

my 2 cents.

 

[MamaP]

To answer @DaddyFish and @Mywifeisgunnakillme (love that name, lol), this is for a 75g SW tank. It's been up and running for just over 2 years. I've used the FX4 the whole time with no issues other than ich, so I want to add the UV to help keep it in check, and (hopefully) eventually it will die off.

The UV Sterilizer I'm looking at is the Pentair 40 watt. With a slow enough flow rate, it should be quite effective for my size tank. I wanted to get one big enough for when I upgrade to a bigger tank.

For reducing the flow, would it be better to adjust both in and out valves, versus one or the other?

@DaddyFish I'm interested to know what you did on your set ups and how it worked for you.

Thank you, both, for the advice!

 

[DaddyFish]

@DaddyFish I'm interested to know what you did on your set ups and how it worked for you.

One of the challenges with inline UV on a canister system is head pressure. Most setups don't have the vertical space to position the UV vertically and above the canister filter. Many also do not have the horizontal space required to plumb from the nearly vertical canister outlet to a horizontally oriented UV, then out of the UV and make the vertical transition to towards the tank.

That leaves most setups with a UV positioned vertically at approximately the same height as the canister. And that means a "droop loop" leading from the canister output to the UV input. You always want the water flowing in the bottom of a vertical UV, not the top. All that plumbing translates to significant head pressure and reduces the flow rate.

I don't believe you will need any type of restriction or bypass. I'm betting that by the time everything is in place, your final flow rate will be in line with the recommended rate of the 40w UV.

 

[MamaP]

One of the challenges with inline UV on a canister system is head pressure. Most setups don't have the vertical space to position the UV vertically and above the canister filter. Many also do not have the horizontal space required to plumb from the nearly vertical canister outlet to a horizontally oriented UV, then out of the UV and make the vertical transition to towards the tank.

That leaves most setups with a UV positioned vertically at approximately the same height as the canister. And that means a "droop loop" leading from the canister output to the UV input. You always want the water flowing in the bottom of a vertical UV, not the top. All that plumbing translates to significant head pressure and reduces the flow rate.

I don't believe you will need any type of restriction or bypass. I'm betting that by the time everything is in place, your final flow rate will be in line with the recommended rate of the 40w UV.

Thank you for the advice. I'll test the gph out today and see where I'm at and go from there. I'll also play with reducing the in and out together to see the effect.

You're right on the spacing. I had planned to mount the UV on the outside of the cabinet so it's easy to get to for maintenance, so I will have the "droop loop."

As far as parts for the plumbing, what all should I have on my list?