Water Turnover?

[monkey_wrench]

Hi

I was wondering if too much water turnover can be bad for the tank?

Can it be 'over-filtered'?

Whats the reccomended turnover?

thanks =]

 

[pangalaticgargleblaster]

there is no such thing as overfiltered, there is however the wrong type of filtration

 

[rabbut]

If the fish are pinned against the tank walls by the current, you have too much filtration. In all other cases it won't be doing any harm

"recomended" turn-over realy depends on tank size and the stocking you are planning to put in it Usualy you aim for a "real" turn-over of at least 5X an hour. Remember that you only get about 1/2 the stated flow on Exturnal filters, 3/4 of the stated for most sump applications and about 7/8ths for internals Real flow is the flow rate after allowing for losses in pipework and after adding media e.t.c

All the best
Rabbut

 

[Truck]

average freshwater tank 5-10x
planted tank 10-20x
standard saltwater tank using berlin method 20-30x
reef tank 30-40x

NB, numbers stated are filters and power heads combined especially in planted or SW tank

 

[OldMan47]

I always use much less flow than the typical forum recommendations. I recognize that it is up to me to remove the stuff on the tank bottom so I don't try to get so much flow that nothing ever settles to the bottom the way Truckasauras would do. If I want good water circulation in a tank to distribute nutrients for plants, I use a power head. The main consideration for a good biological filter or even a chemical filter is the volume of filter material that will fit into your container. I use a Rena XP3 on a 120 gallon tank as the only filter but it will hold several litres of media so it is plenty. I have a HOT Magnum that is rated for 250 gallons per hour but has very little space in it for biological media so in my mind it is almost worthless. It will stir things well in a small tank and remove the stuff that I remove with a gravel vac but who cares. That is what a gravel vac does for a living. For a chemical filter, like you want following medication, contact time for a proper reaction is a must. If the filter is balanced to give lots of flow with a small filter volume, you just don't get the contact time. If the filter has lots of volume and lower flow, you get efficient adsorption of the medications. Don't worry about flow rates for a freshwater tank. For years, all successful keepers of freshwater had nothing but air to move their water through their filters but the fish thrived. Those filters had nowhere near the flows we now get with power filters but they did a great job on all but the tank sediment. The real downside to those filters was the difficulty getting the air flow right to optimize water flow.
I have never kept salt water fish and have no opinion about their flow needs.

 

[waterdrop]

OM47, truck,

As a "re-beginner" in the hobby I have found this very topic increasingly disconcerting myself. I've been fascinated by the better fishkeeping and fish-oriented water chemistry fundamentals I've learned so much better by being here on the "New to the Hobby" forum of TFF, and yet I've also been interested in the theory and concept of planted tanks and have been reading a lot over the last year in the TFF planted tank forum and the AGA journals and other sources. A while back I attended the big AGA plant conference out of beginner interest in the plant stuff. What I seemed to find was that there are different paths that seem to lead to different types of success with planted tanks and this leads to a bunch of potentially confusing things floating around out there for us beginners (at least it seemed to me.)

I've been really impressed with the knowledge and techniques of the group of experienced planted tank enthusiasts we have here on TFF and I think they are pulling me most strongly in their direction of fairly high-tech implementation of a planted tank where high (10x-type) turnover and/or powerhead supplementation to try to eliminate tiny pockets of ammonia (even though the kits are measuring zero overall) that they say will be the trigger for algae. These techniques seem to be backed up by experts who are on other planted forums and drop in here every now and then.

But at the conference I found that other ways of enjoying plants in the aquarium environment seemed to be alive and well and also offer interesting things to learn. It seemed to me that the "lower-tech" methods (for lack of a better term for this pathway) written about by Diana Walstad were in evidence among dozens and dozens of the experts there, despite probably the majority of people there being more focused on the higher-tech methods. Many aspects of Walstad's lower-tech methods seem similar to what you are describing OM47 and at this point in my learning I find it distressing that there sometimes seems to be a level of animosity between the practitioners of these different paths to successful planted tanks. To me it seems that understanding what's really going on in an aquarium with mostly plants but also fish is a very complicated thing and that both camps have good insights to offer but that even when added together there is still lots that's not well understood. I'd be interested in your thoughts concerning these different approaches.

(Sorry monkey_wrench, don't mean to hijack, its just that forums seem to provide a very imperfect framework for discussions of this type.. always kind of find myself wishing there could just be an evening of sitting around in person for a discussion of this type.)

~~waterdrop~~

 

[OldMan47]

That was a knee jerk reaction that I have when I see a post that just says more is better no matter what, WD. I find far too little thought in many filter posts that I read. There is the "I use xxxx brand and everything else is worthless" approach and the bigger and faster is better approach and several others. I was trying to point out that there are no absolutes and that statements about a specific turnover rate were very close to meaningless. The important thing to look at with anything we do is the factors we find important in the equipment and how it is best achieved. For biological filtration, that is growth surfaces for the bacteria. For chemical filtration, that is reaction surface area, type of media being used and contact time. For mechanical filtration, the important factor is flow rate and filter media particle size capability. Because I find mechanical filtration beyond removing floating particles as meaningless, I favor large filter volumes with appropriate media. If I move the power head from my XP1 over to the XP3 and leave it on the same tank as always, it will not affect that tank's biological filtration but will cut the flow in half. It would also mean blowing around all the fish that live where the XP1 belongs because of the high flow rate from the XP3 impeller. Both biofilters will work just like before the switch and if I had chemical media, the new high flow one would be less efficient while the new lower flow one would be more efficient because of the change in contact time. .

 

[waterdrop]

Yes, completely agree with all your discussion there about flow rate as pertaining the various important aspects of filter design. All those things should be excellent information for the OP to help him understand the differences between flow rate choices and media volume choices.

But, even though its off-topic, I was still hoping you'd comment about planted tank approaches. Was wondering if you had any opinion about Walstad's book and/or those "slower flow, soil substrate, fewer water changes" approaches vs. the higher-tech (high light, EI, high flow) approaches in tanks with lots of plants. Now that I've read more about these Walstad type ideas, its very interesting that there seem to be overlaps with some of the old 50's 60's behaviours of tanks that were left to age more. Its interesting to me that although we now know pretty much all the aspects of why the water/fish aspects of this were quite bad in the long run, there may have been aspects of this that were quite good for plants. -wd-

 

[OldMan47]

I have a Walstead style tank that is growing plants very nicely. I can't say that I bought in on all of the aspects such as never changing water. I still change water on that tank 3 or 4 times a year and run a sponge filter on it rather than just a power head. The soil substrate is working out and I use no fertilizers or added CO2 on it. My soil cap is a coarse sand / fine gravel, you get to choose the best name. I have replaced the fish once because I needed a home for some new goodeids. The goodeids do not require a heater so the tank is now running with the heater unplugged. The fish that came out of the tank went into my 120 community tank. That tank is a regular Noah's ark compared to most of them.

 

[rabbut]

While high contact times are good, if flow is too low, you don't get the ammonia into the fitlter quickly enough to process it out. There will be an equillibrium point where there is sufficient flow and contact time to remove the most ammonia from the tank, and adding more flow or contact time will then start to reduce filter efficiency again Unfortunately, the turnover rate question has no simple answer like contact time is most important, surface area is most important or flow rate is most important or media volume is most important. In reality, they are all qually important and interdependant on eachother

 

[OldMan47]

Well put Rabbut. You are correct that there is a balance that must be struck.

 

[monkey_wrench]

I see..so it doesnt matter wheather u have 50x water turn over, if contact time, surface area, media volume and the correct filtration is imbalanced then your tank isnt being filtered properly..

right?

thanks for the replys

 

[OldMan47]

I think you got the concept Monkey wrench. You want a decent flow and a large canister if you have a canister type. For a HOB, you want one with flexible filter media, like an AC, so you don't end up with proprietary filter cartridges.

 

[kcharley]

I think you got the concept Monkey wrench. You want a decent flow and a large canister if you have a canister type. For a HOB, you want one with flexible filter media, like an AC, so you don't end up with proprietary filter cartridges.

Maybe I don't understand something but what works for me on the proprietary filter cartridges is when they get plugged beyond cleaning I use a utility knife to remove the medium just leaving the frame. I then wrap the frame with some filter floss purchased by the bag. It doesn't hold charcoal but then again I don't use charcoal generally. I can always put that in a nylon sock and put it in the filter if I need it.

Sorry for going off topic but I hope the idea helps somebody.

Greg

 

[waterdrop]

I think you got the concept Monkey wrench. You want a decent flow and a large canister if you have a canister type. For a HOB, you want one with flexible filter media, like an AC, so you don't end up with proprietary filter cartridges.

Maybe I don't understand something but what works for me on the proprietary filter cartridges is when they get plugged beyond cleaning I use a utility knife to remove the medium just leaving the frame. I then wrap the frame with some filter floss purchased by the bag. It doesn't hold charcoal but then again I don't use charcoal generally. I can always put that in a nylon sock and put it in the filter if I need it.

Sorry for going off topic but I hope the idea helps somebody.

Greg

That's a nice tip Greg. From my reading I think we get a lot of beginners who have come home with filters that they much later realize are designed with cartridges planned to help the manufacturer make more money rather than give the hobbyist the needed media flexibility that is desired after they are experienced. But they've already spent the money on the filter and they need to get some value out of that expenditure, so figuring out ways to make it work is important.

We try hard to steer the really early beginners in the direction of the really flexible internals, AC HOBs and open-tray cannisters, but usually by the time they find TFF, they've already bought a "kit" aquarium or a filter that was recommended by the LFS and the filter choice is in the past.

Glad that works for you, I'm going to try to remember it as advice to pass along to beginners with cartridge frame style filters.

~~waterdrop~~