# Filters with flow adjustment, does it lower gph?

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Hey guys,
I got a fluval u1 for a 6.6 tank and has the perfect gph for my planted tank. I was just curious if I lowered the adjustment flow, does that lower the gph?
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Yes.

#### FatherLandDescendant

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GPH is calculated at full output no media and can be affected by factors such as above/below/even with water line, how far the draw/return of water is, media type, clean or dirty impeller..... Even age of a drive motor can affect GPH.

#### DesignZ

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Alright, I was curious cause the current is strong in that particular area.

GPH is calculated at full output no media and can be affected by factors such as above/below/even with water line, how far the draw/return of water is, media type, clean or dirty impeller..... Even age of a drive motor can affect GPH.
So how would I find the modified gph for a lowered adjustment?

#### FatherLandDescendant

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So how would I find the modified gph for a lowered adjustment?
Time how long it takes it to fill a 5gal bucket, divide 3,600 by the amount of seconds it takes and that should be a close enough estimate of your final GPH.

There are 60 minutes in an hour, 60 seconds to the minute, 60X60=3,600 seconds in an hour.

So if it takes you 5 seconds to fill a 5 gallon bucket with your filter (3600/5) would be 720GPH, or 9 seconds (3600/9) would be 400GPH. If you use a digital stop watch you can get it even closer (3600/6.42) would be 560.747664GPH and so on

#### DesignZ

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Time how long it takes it to fill a 5gal bucket, divide 3,600 by the amount of seconds it takes and that should be a close enough estimate of your final GPH.

There are 60 minutes in an hour, 60 seconds to the minute, 60X60=3,600 seconds in an hour.

So if it takes you 5 seconds to fill a 5 gallon bucket with your filter (3600/5) would be 720GPH, or 9 seconds (3600/9) would be 400GPH. If you use a digital stop watch you can get it even closer (3600/6.42) would be 560.747664GPH and so on
Thanks planted tanks should have 10x gph for tank size correct? I'm hearing from 2-10x tank size

#### FatherLandDescendant

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Thanks planted tanks should have 10x gph for tank size correct? I'm hearing from 2-10x tank size
I've heard 4-5, right now I'm around 5 and my new filter will also be around 5, seeing as how I'll probably run both that's around 10. Not taking into account the different variables that can affect flow so less than 10 but greater than 5.

#### AGUILAR3

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I would think 10x or more due to the lower actual rating once media is inserted. I picked up a HOB rated at 160gph(8x) on a 20g and its barely keeping up.

#### Fissure

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Never got that about the x 10 thing. I got a 110G tank and an Eheim 2080, wich is the biggest Eheim canister. With filter media and the shortest possible intake and outblow hoses I get around 700 liters per hour. That would mean i would need around 3-4 eheim 2080 canister filters? Sounds pretty insane to me and those who own even bigger tanks would have a though time matching that "rule"?

#### FatherLandDescendant

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I would think 10x or more due to the lower actual rating once media is inserted. I picked up a HOB rated at 160gph(8x) on a 20g and its barely keeping up.
My power filter is actually rated at 280GPH which on my 40gal is 7 times. It does a fair job of keeping up but I can't direct the flow the way I want and still have my top in place. I have a dead spot on one end of the tank and will until I can direct a flow length wise through the tank. HOBs and power filters push water width wise leaving those dead spots.

#### Ghia

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GPH isn't everything, just a rough rule of thumbs. The effectiveness of a filter depends a lot on how and how fast the water passes through the filter media. Some filters don't have a good flow distribution through the media, .i.e. the water finds the path of least resistance and can thereby bypass some of the media. And if it flows too fast, the bacteria don't get enough contact time with the water to do their job.

Measuring the actual flow of a Fluval U-series filter is practcally impossible unless you use only the direct outflow nozzle (which I personally find less useful).

#### DesignZ

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True GPH isn't everything but circulation in a planted tank is, I modded my U1 and cut half the foam out and placed ceramic biomedia upon the top portion for better growth. I have no problem with bacteria sticking to the media as mode of my ceramic are in the open "ports" where the water gets taken in, circulation was what I was curious about and the 2-10x rule. Mine is exactly 10x (or so they say) but seems a bit strong in that area and was worried if it'd be problematic for my tanks inhabitants.

#### FatherLandDescendant

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True GPH isn't everything but circulation in a planted tank is, I modded my U1 and cut half the foam out and placed ceramic biomedia upon the top portion for better growth. I have no problem with bacteria sticking to the media as mode of my ceramic are in the open "ports" where the water gets taken in, circulation was what I was curious about and the 2-10x rule. Mine is exactly 10x (or so they say) but seems a bit strong in that area and was worried if it'd be problematic for my tanks inhabitants.
Depends on the inhabitants. Do they look like they struggle with the flow? Fish like angles even betas don't like high flow tanks. Does the flow keep fish isolated to one area of the tank? Or do they seem to enjoy it? My albino Cory's have a habit of swimming in a group on the end of the tank where my power filter is about 9pm every night and seem to enjoy it.

#### DesignZ

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Depends on the inhabitants. Do they look like they struggle with the flow? Fish like angles even betas don't like high flow tanks. Does the flow keep fish isolated to one area of the tank? Or do they seem to enjoy it? My albino Cory's have a habit of swimming in a group on the end of the tank where my power filter is about 9pm every night and seem to enjoy it.
I have a betta and 2 ghosts, the betta sometimes swims into it on occasion and swims away quickly my ghost shrimp avoid the area altogether usually. And usually the betta swims around it.

#### FatherLandDescendant

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I have a betta and 2 ghosts, the betta sometimes swims into it on occasion and swims away quickly my ghost shrimp avoid the area altogether usually. And usually the betta swims around it.
Broad bodied fish and fish with long flowing fins don't typically like high flow. Betas come from still waters and can live in mud puddles. It was once put to me that high flow for betas is like a slow death on a non-stop treadmill for them. As for the shrimp I have no idea, never tried keeping shrimp.

#### DesignZ

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Broad bodied fish and fish with long flowing fins don't typically like high flow. Betas come from still waters and can live in mud puddles. It was once put to me that high flow for betas is like a slow death on a non-stop treadmill for them. As for the shrimp I have no idea, never tried keeping shrimp.
He usually avoids that area though and people said he'll get used to it. It's only the top minimal left portion of my tank (basically a little line) so if I lowered the flow, would it hurt the tank and circulation? As the u1 is 66 gallons per hour and is precisely if not close to 10 x 6.6 gallons.

#### DayOlder

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My endlers actually swim against the flow completely into my HOB. I swear they line up 3 abreast and take turns swinging into the HOB. It looks like they are at Disneyland waiting in line for their turn.

#### AGUILAR3

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My endlers actually swim against the flow completely into my HOB. I swear they line up 3 abreast and take turns swinging into the HOB. It looks like they are at Disneyland waiting in line for their turn.
If the water is high enough in my 20, the water from the HOB shoots straight across the surface and guess who's there to enjoy it?...about 20 guppy fry. Some of the smallest fry get tossed around if hit right but they recover and get back in line. I usually toss in a pinch of flakes and enjoy the show :hihi:

#### Diana

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My Clown Loaches would surf when they were younger. I used a powerhead a few inches below the surface, and lined up parallel with the front of the tank. (6' long tank)
The Loaches would get into the flow and sort of beat up stream until they got close enough, then quit fighting it and get shot downstream about 4-5' along the front of the tank. Then recover and come back for more.

I usually aim for 10x, combined filter and power head, per manufacturer's ratings.
I am sure I never actually got 10x, except when I over did it and added perhaps 15-20x worth of equipment.

A single path of stronger water flow, with most of the tank being in gentle motion seems just fine for the flat bodied or long finned fish that do not like too much water movement.
Angels, Gourami, Betta, long finned Danios, long finned Goldfish and others seem to stay out of the main flow, but are fine with the slower moving areas. Especially when food showers down out of the main flow, drifting right past them!

#### DesignZ

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My endlers actually swim against the flow completely into my HOB. I swear they line up 3 abreast and take turns swinging into the HOB. It looks like they are at Disneyland waiting in line for their turn.
That's so cute, my tank is unfortunately not as big XD I have a 16" deep tank aha, and the flow is just straight and down.

My Clown Loaches would surf when they were younger. I used a powerhead a few inches below the surface, and lined up parallel with the front of the tank. (6' long tank)
The Loaches would get into the flow and sort of beat up stream until they got close enough, then quit fighting it and get shot downstream about 4-5' along the front of the tank. Then recover and come back for more.

I usually aim for 10x, combined filter and power head, per manufacturer's ratings.
I am sure I never actually got 10x, except when I over did it and added perhaps 15-20x worth of equipment.

A single path of stronger water flow, with most of the tank being in gentle motion seems just fine for the flat bodied or long finned fish that do not like too much water movement.
Angels, Gourami, Betta, long finned Danios, long finned Goldfish and others seem to stay out of the main flow, but are fine with the slower moving areas. Especially when food showers down out of the main flow, drifting right past them!
Ah alright, I was just worried because he tends to swim near it and gets blown back a bit sometimes aha. Not strong where he smacks the glass, just a gentle nudge.

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