# A question about double filtration+increased flow



## Witblitz (Nov 7, 2013)

I have a Tetratex EX700 (184 gallon/hour flow), my nephew also had one which he sold me for a dime.

My question to you is, do you think it will work if I connect them in-line? This would effectively double the filtration quality?

Then another step to increase the flow: I have an old internal filter capable of moving 2000 liter/hour (500 gallons) which has a connection to pump water only (no filters connected works like a power head instead), if I was to connect the EX700's intake pipe directly onto this power head to increase the flow, will this work?

Example :










The idea is basically to over filtrate my African Cichlid tank.


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## joescaper1 (Feb 14, 2013)

The flow can only be as great as the return hose will allow. If the flow is increased beyond that, it puts pressure on the fittings. If they blow apart, you will have a real mess.

I would think running them separately will actually give you more filtration, run in series the second filter will process water that has already been filtered. Also, the more inlet hoses you use, the more flexibility you have to customize currents within the tank.

Joe


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## joescaper1 (Feb 14, 2013)

One other thing, canister filters are not pressure vessles, the motorized pumps in each evacuates the water. By hooking them in sequence, water from the first pressurizes the second which pressurizes the third. Also, the maximum flow from the sequence would be the same as the flow from the pump with the maximum GPH.(It would not be 500 + 184 + 184, it would just be 500. Which is more than the canisters are rated.)

Joe


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## Witblitz (Nov 7, 2013)

What if I only used a single cannister? And removed its impeller to get the 500 gallon flow from the stronger pump?


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## CjCichlid (Sep 14, 2005)

I agree with Joe...
I would not hook them together like that as they are not meant to handle that kind of pressure. Not to mention you will indeed get more use out of them by running them separately. Interesting thought but...


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## joescaper1 (Feb 14, 2013)

While I am not an engineer for Tetratec, I do know that some systems, ie. reverse osmosis and deionized water, have a maximum waterflow (generally 3 gallons per minute) in order to function properly. Any faster than that and the water does not stay in contact with the medium long enough to accomplish ion removal. The Tetratec EX700 has a canister volume of 6.6 litres, at 184 GPH the canister evacuates every 17.5 seconds. If you triple the volume of water flowing through the system, the canister now evacuates in 5.8 seconds, possibly not giving the biomedia or cabon the contact time they need to do the job as a filter (mechanical wouldn't make any difference). I am reasonably certain that the engineers at Tetratec would have put a 500 GPH pump on it if the media configuration could handle it.

If you can triple the volume of the biomedia (remove other filter elements to create additional space) it would get you back to the same contact time as the 17.5 seconds.

If it is something you feel strongly about trying. Hey, why not? We don't learn anything if we don't try. And if you were to lose the canister, it's your dime.

Joe


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## spotmonster (Nov 23, 2006)

Interesting thought but I don't see where you would be gaining anything. You will get much more filtration by using them as intended. Utilize the power head to shoot water in areas that are stagnant, and to keep particles in movement until they are sucked up by the filters.

Down the road if you feel you want more flow, upgrade to something like a FX5. By then, you'll be hooked and can ultilize the smaller filters on your next tank or 2 :thumb:


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## ozman (Sep 7, 2012)

an interesting thread.
i don't see any mention of tank size, stock etc.????????? that would determine your filtration needs.

but as far as you go with your idea....i agree with other posts.


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## Witblitz (Nov 7, 2013)

Ok I tested this setup for the past 4 days and I have to agree with Joe with my findings 

The cannister evacuates too fast for effective bio removal, while most debris get removed the water started to turn a tinge of yellow due to increased flow through the cannister ie. not enough contact with bio filter removal media. I will now disconnect the power head from the system and run the cannisters independently. Lesson learned I suppose.

The tank is an african cichlid 70 gallon (14 fish between 2-5" + 1 pleco 6")


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## joescaper1 (Feb 14, 2013)

If you hadn't tried, you would always wonder. I am the same way.

Good Luck
Joe


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