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Preferred flow rate?

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Hi guys!


Over the weekend I rebooted a several year old overgrown mr. Aqua 12 and added some PRL


My filtration is an Eheim 2026 Pro II with ADA style lily pipe

I also added a small hang on the back Topfin 10 at the other end of the tank with fluval prefilter sponge to have more aeration/sponge filter/easily swappable purigen.


So, obviously this tank is capable of really churning the water.  

I normally run the Eheim at about 20% which creates enough current the push water all the way down the front of the tank and back again to the intake, here's an old pic to show the filter setup




The HOB is now on the left side, finally my question:


I've noticed the shrimp seem happier and are more spread out when I turn off the filter or have what I would consider really low flow, otherwise they seem to stick around under the lily pipe or toward the glass all around the tank.


I stuffed some filter sponge into the HOB pipe to reduce its flow and set the Eheim around 10%, there are no bubbles or things blowing around from the HOB but the water flows completely across its output shelf.  The Lily pipe doesn't create noise or bubbles when raised slightly as in the pic above. There is a slow flow all around the tank, the plants don't wave perceptibly.  


However this causes me to consider the impact this is having on oxygenation.


I've often seen over filtration recommended for shrimp tanks, how do you guys deal with the flow that creates?  What kind of flow do you have in your shrimp tanks?


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Great looking tank and great question zodduska!


I often have thought about the pros and cons of flow rate and oxygenation as it is vital for baby shrimp survival in my opinion. A little background, all of my 17g aquariums run Eheim 2213 canister filters, which produce a fairly good amount of flow, add a SS Filter Guard and the flow is ever so slightly cut down. I have the same outcome as you when I turn my filters off, you start seeing the shrimp become "more active". We want decent flow for water overturn, but the point of oxygenation becomes breaking the surface of the water, and in my setup I use a "Choice Bubbler" this attaches to the output to produce micro bubbles without the use of other equipment. With this small adjustment I have noticed back when I started and even today an increase in baby survival.


So with all that said, yes I feel the stronger flow does possibly stress the shrimp slightly, but not to the point to cause them not to be active, eat, or breed. There is a sweet spot, but the point is that you don't need 500gph for a 10g shrimp tank to oxygenate the water, you can simply make do with what you have, and add modifications such as a spray bar, or choice bubbler to help produce water agitation (breaking the water) and/or bubbles.


Maybe this was a bit much, but I have tossed this around in my head for a long time since I am a believer of canister filters. The one thing they lack is a better way to oxygenate the water such as sponges, HMF, and UGF.


Hope that helps a bit, and I hope I actually answered your question.

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Thanks, DETAquarium!  


I've watched some of your Youtube series and found it very enjoyable!  Very nice setups you have!  


Your answer is helpful and I also believe there is a balance to be struck between flow and proper oxygenation, the Choice bubbler is a great idea..  Personally, I may be too attached to the glass lily pipe because I like how it looks and it spreads the flow over a larger area compared to my eheim pipe. With a shallow tank like this it seems difficult to direct the flow in such a way as to minimize the current while still maintaining good circulation and eliminate deadspots, the small HOB should help I think.  Last night I turned the current up slightly because the shrimp looked a little lethargic, I think it's closer to where I want it to be now.


I'm a little confused as to what is actually required to oxygenate the water, I've read that as long as you have the water surface being turned over it should be sufficient but I wonder how much is really enough.. does it have to be noisy?


As a side question the 20 PRL were added to this tank Monday evening and I'm having trouble getting them to take prepared food in a Pyrex petri dish, they don't even really investigate it.   I'm wondering if the food may be too old as it was bought a couple years ago, I tried Lowkey Secret food, Lowkey Ultra Supple, Shrimp King Complete.  The food smells okay and was always dry thanks the the moisture absorbing packets.  I may have to get some new stuff.  I took the SKC from the dish last night and dropped it right in front of a shrimp, he ate it a little and another shrimp walked up to it, tasted it then walked away.. Ha.

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  • 3 months later...

it looks like your lily pipes could be leaned at an angle to direct more of the waters movement parallel to the surface. A dead sopt means less turbulence but the pH, O2, GH etc...are the same essentially and thats where they like to chill which makes it the best spot to observe them. It makes it the best place clean too ?

Every tank I have has two sources of filtration minimum. Less flow but more of it ?

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