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Tank volume turnover?


Rob

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I'm pipe dreaming about getting a couple of larger tanks (6' x 2' x 2'). I need to consider what filtration I'm going to use.

The Baensch Atlas (vol. 1) says to have a volume turnover of about 3-4 times an hour (ie for a 100L tank the filter should pump out 300-400 L/hr). The LFS says that a volume turnover of once per hour is adequate, with twice an hour being good.

I realise that it does depend on stocking levels in the tank, but assuming an average stocking level for a tank with only a few live plants what volume turnover would people recommend?

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Rob said...

> ... assuming an average stocking level for a tank with only

> a few live plants what volume turnover would people

> recommend?

I know 'it depends' is a dreadful answer, but one factor to include

in your calculations is how often you're able/prepared to change

water. There'd a huge filter load if you weren't diluting the

dissolved wastes significantly on a regular basis. Arguably, if

you're changing water often enough, the filter can be quite small

since it only has to remove particulate matter and isn't required

to do much biological filtration...

Just my thoughts.

Andrew.

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I'd say go with the 3-4 times per hour. I don't think only 1 time per hour would have a huge impact on the biological filtration, a lot of that would be done inside the tank if the filter can't handle it. But, it would make a pretty big difference in the amount of debris floating in the tank, imo. And keep in mind that filters are usually rated higher than they actually flow. Hmmm, a 6'X2'X2' tank would be...Ummm...680liters. Wow, that's a beast.:) That'd mean you'd need about 2800 liters/hour. I'd suggest 2 fluval 404s as an absolute minimum. Assuming you get two that actually flow the amount they're rated at,(None of my 3 even come close) then that would be turning it over 4 times. I don't know if there are any higher rated cannister filters that are easy to get, I can't find any. You might try making a sump and throwing in a couple of powerheads as pumps, fabricating some trays to hold the media and sponges. Lemme look up some specs for pumps...Something like an Eheim 1264 which is rated at 4500LPH as the pump(Or two of them for a bit of redundancy) should give you more than enough flow even with the 1 meter or so head I'm guessing you'd have.

Wow, bigger than I expected. Some thoughts anyway, hope it helps.

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Just noticed there's an Eheim cannister filter, the 2260, that's rated at 1900 L/Hr. I'd bet for the price of one of those you could probably get four fluval 404s. But 4 cannisters would be a bit ridiculous.;)

Speaking of ridiculous, I keep reading some suggestions on water change amounts that makes me wonder how people that follow them actually keep fish. For example suggestions that in a heavily packed 20ish gallon tank that you should do 15% monthly water changes. And 15% biweekly will make the fish "really happy."

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Hi Rob;

I noticed that you were thinking about a tank 6'x2'x2'. One of my freinds has a marine tank of this size and it looks great, but it dose protrude a significant way out into his loung room. Another of my freinds just bought two 200cm X 60cm high X 40cm back (7'x2'x1.3'). These tanks also look fantastic especialy since he has them end to end :o and they don`t protrude out into the loung room. It would take about the same amount of glass and i personly think they look better. Any way thats just my thoughts and it will look great either way. :D

Regards

Andrew.

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I've got 3 tanks in my lounge with the following filter setups:

1. Diameter 900mm, 1000mm tall, volume 580L. Has 1 Big Borneo Tiger + 1 Big Mystus Catfish. Filter = Trickle Filter using Effisubstate + Siporax media + Spa Pool Pleated Cartride Filter. Turnover = 4000L/H using Grundfos FP3 Pump (Now Oase' 4000).

2. 1800 x 600 x 600mm, volume 680L. Has 2 Big Oscar, 2 Big Jags, 2 Big Chocolate Cichlids, 1 Leporinis, 1 Very Big Cigar Shark (330mm). Filter = Trickle Filter using Effisubstate + Siporax media + Spa Pool Pleated Cartride Filter. Turnover = 6000L/H using Grundfos FP4 Pump (Now Oase' 6000).

3. 2400 x 850 x 650mm, volume 1200L. Has 10 Adult Discus (now), 200 Neons, 50 Rummy-nose, 6 Blue Rams, 6 Cerviceps, 20 Black-line Flying Fox. Filter = Trickle Filter using Effisubstate + Siporax media + Spa Pool Pleated Cartride Filter. Turnover = 6000L/H using Grundfos FP4 Pump (Now Oase' 6000).

All tanks run very clear. Up close on the 8' tank you cannot see any muck in the water right through the 2400 length (not even any cloudiness).

These tanks have turnover rates between 6-9 times per hour. Some may consider it overkill, but they are amoungst the cleanest tanks I've seen in the country.

Go for the biggest pump you can afford to buy and run. Remember, a pump will use close to its purchase price (approximately) in electricity every year. You cannot over-filter but you can under-filter.

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  • 3 months later...

Hi Warren

I don't think you can over filter a tank. And your water-turnover is not an overkill. My new filter turns my tank 10 times per hour over. All done without a 20 HP pump. The bigger the turnover, the more oxygen the bacteria get, they healthier they are, and subsequently the less likelihood of diseases. So keep on turning the water over.

John

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Don't forget another important variable in biological filtration, the amount of filter volume (the amount of volume the media occupys), or probably more importantly the amount of surface area provided for bacterial colonisation. This controls how many bacteria you have available to convert wastes. If you only have a small bacterial population, it doesn't matter how many times you turn the tank volume over, the bacteria won't be able to process the wastes fast enough. Bacteria can only convert watses at a certain rate, if you use a high turn over rate you may just be supplying them with wastes faster than they can convert them. Beyond this point any extra turnover is just improving the mechanical filtration, helping to clear the water of debris faster.

There are rules of thumb out there for the amount of filter volume that you should provide for a given tank volume, but I can't remember what they are off the top of my head.

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Hi Goldie

My reply was for Midas and Co. It was not intended for you directly. But for your benefit, an u/g filter for instance, provided it is is good working order which, unfortunately no one ever knows, is a very big biological filter. Populated by many, many litlle bacteria which, keep your aquarium healthy.

John

PS. "The u/g filter working well or almost not at all, is another topic, a hot one"

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Hi Ira

Speaking of ridiculous, I keep reading some suggestions on water change amounts that makes me wonder how people that follow them actually keep fish. For example suggestions that in a heavily packed 20ish gallon tank that you should do 15% monthly water changes. And 15% biweekly will make the fish "really happy."

Is there any chance that you give as either the link or a copy of the source of that "statement"?

As far as I know, and I am not talking about a goldfishbowl, the smaller the tank, the more frequent the water-changes, as long as the number of fish is proportional.

John

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:D <---big grin for John1. ty I was not taking it personally :wink: However it is great to read the posts and glean whatever I can and I am sure others are doing the same. My set up is very simple .................................at the moment. We can all dream.
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Try www.fishprofiles.com's messageboard, John. I'm sure you'll only need a few minutes searching to find several people suggesting 15%/month or somewhere in that range. And the 15%/2 weeks bit was some american TV pet show when the guy was showing and setting up about a 5 gallon tank.

I'm actually going to twice weekly 50% changes in my 400L tank for a little while. Not happy with the nitrate levels with a weekly 50% change.

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Hi all

Yes, Ira, what this guy probably meant was changing 15% / month in his tank full of plastic plants and plastic fish. :D

No real aquarist would even consider that amount as realistic. It could also have been posted on the 1st of April.....

John

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For what they are worth, may I quickly make reference again to some articles I've previously written:

http://www.fnzas.org.nz/filtration.0.html

http://www.fnzas.org.nz/filtration-2.0.html

http://www.fnzas.org.nz/filtration-3.0.html

http://www.fnzas.org.nz/aquarium-conditions.0.html

These should help most people who are unsure about filtration and hourly turnover.

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