Discussion about Over Filtration

[f1stephens]

When you partially close a valve on a pump discharge, "throttling" the flow, you add more head to the pump causing it to work harder, but pump less - may not make sense here, but I would encourage you to google 'pump curve' to better understand. By throttling you are basically moving the operating point of the pump to the left on the pump curve. Another way to visually 'test' this is to raise (add head) or lower (reduce head) your pump discharge (specifically the highest point of the discharge).

[ptran]

When you partially close a valve on a pump discharge, "throttling" the flow, you add more head to the pump causing it to work harder, but pump less - may not make sense here, but I would encourage you to google 'pump curve' to better understand. By throttling you are basically moving the operating point of the pump to the left on the pump curve. Another way to visually 'test' this is to raise (add head) or lower (reduce head) your pump discharge (specifically the highest point of the discharge).

Stephen, thanks for chiming in on this topic. Are you Mechanical eng background by any chance?
So in English it's not good for the pump right?

[Austy16414]

When you partially close a valve on a pump discharge, "throttling" the flow, you add more head to the pump causing it to work harder, but pump less - may not make sense here, but I would encourage you to google 'pump curve' to better understand. By throttling you are basically moving the operating point of the pump to the left on the pump curve. Another way to visually 'test' this is to raise (add head) or lower (reduce head) your pump discharge (specifically the highest point of the discharge).

Is there a google translate for engineer talk to lamest terms??

Let me see if I follow.. you're saying that throttling the pump will increase the height (or pressure?) of the output, but flow capacity will be reduced?

[danielp]

Anytime you have a pump or any type of flow device that's rated at X flow in GPM and you introduce a ball valve to it and partially close the ball valve you are introducing back pressure.

The impeller isn't controlled by the valve and it keeps working at the same rate.

impeller draw + reduced flow = back pressure

I have several types of groundwater pumps at work and we use these type methods to maximize their efficiency when we are pushing the curve at depth.

[blaciarmd]

The question should be how efficient is your filtration rather than How fast yo can pump water from one container to the next container. We can get hung up on flow rates, but would everyone agree that biological filtration is the most important type of filtration. Without biological filtration water truly wont be healthy for fish. To maximize biological filtration you need a place for this bacteria to live (media and a lot of it to create the surface area needed) and contact time. Even with chemical filtration that media needs to stay in contact with the water long enough to absorb or adsorb molecules of polutants. Nothing beats a good water change, keeping stocking levels down and not overfeeding. Pumping 1000g an hour on a 75g tank may be overkill and may not be beneficial to all fish especially if they dont appreciate a current.

[Austy16414]

Agreed^

Without bio filtration, chemical and mechanical are meaningless (they're both pretty superficial anyhow). I run almost exclusively bio media in my filters, with the exception of some sponges and purigen.

I like to have a heavy flow in my tank because it keeps the water oxygenated and doesn't allow detritus to settle. Obviously if I was keeping frontosa instead of tropheus this would have to change. At the end of the day, you've gotta tailor your equipment to the stock you're keeping, because there is no blanket statement that can cover all fish

[ptran]

The question should be how efficient is your filtration rather than How fast yo can pump water from one container to the next container. We can get hung up on flow rates, but would everyone agree that biological filtration is the most important type of filtration. Without biological filtration water truly wont be healthy for fish. To maximize biological filtration you need a place for this bacteria to live (media and a lot of it to create the surface area needed) and contact time. Even with chemical filtration that media needs to stay in contact with the water long enough to absorb or adsorb molecules of polutants. Nothing beats a good water change, keeping stocking levels down and not overfeeding. Pumping 1000g an hour on a 75g tank may be overkill and may not be beneficial to all fish especially if they dont appreciate a current.

Agreed. I believe sum is the most efficient way to go: more economical, huge bio capacity, and flow rate can be controlled by using different pump size.

[rage]

My 2c.
Maxing out bio capacity would be most beneficial but of course it is limited by your fish load. You cannot have more bacteria than the food available to feed them.

Flow rate should depend on the type of fish you have and how much turbulence and oxygen you want in your water and it is best controlled by using the correct pump that give you the flow rate you desire, not by throttling.

Contact time for your filter media is a bit misleading. Higher flow rate does not mean low contact time, the water might flow thru your media faster but it will also come back around faster.
High flow rate then improves your mechanical filtration because it allow detritus more chances to be trapped.

[SunnyHouTX]

When you partially close a valve on a pump discharge, "throttling" the flow, you add more head to the pump causing it to work harder, but pump less - may not make sense here, but I would encourage you to google 'pump curve' to better understand. By throttling you are basically moving the operating point of the pump to the left on the pump curve. Another way to visually 'test' this is to raise (add head) or lower (reduce head) your pump discharge (specifically the highest point of the discharge).

The pump doesn't "work harder". It just works less due to increased head. The rest is spot on.

[ptran]

Sunny, you can't vote again bro!

[SunnyHouTX]

Get off it dude. I'm joining the discussion

[specialone0812]

My opinion:
chemical and mechanical filters are used to trap debris,fish waste etc. more for cleaner look of your tank water. powerhead or some added flow are to help with this purpose. however, there is also room in mechanical for bacteria to live in ( like canister filter)
bio filter or bio-mechanical filter are where bacteria will live in open media and bacteria need surface,oxygen and nutrient(fish waste or food) to grow and produce.

I have done a little experiment with two tanks(both are 75g,no substate,same stock with african cichlids): one with eheim 2260 and another tank with a sump (600gph pump).
i perform WC every week, same amount for both tanks. The tank with eheim usually gets cleaner look ( very few solid particle floating in water column) but nitrate/ammonia level are often higher than the tank with the sum.
I agree with Daniel above. I would do 4-5 times over-filtration with different kind of filters to have "clean" by all means water.

[geoff_tropheus]

I am a mechanical engineer for 10 years, all of which I have worked in maintenance and reliability of rotating equipment such as pumps, compressors, gear boxes, agitators etc... In addition to this I have been avid aquarist for 27 years. During this time, I have kept aquariums ranging from a cup to 380 gallons with all kinds of filtration types all kinds of media gizmos and gadgets.

Nearly all home aquarist filtration systems utilize a mag drive pump. A Mag drive pump is basically driven by magnets and a generated electrical field and has no mechanical seal. I don't want to go into specifics, but with mag drive pumps the motor is enclosed and the heat generated by it is removed by the pumping fluid, meaning the aquarium water. If you dead head or pinch off your discharge you are reducing the amount of flow in an around the impeller assembly. Heat is bad, because it can distort and break things. This is also why it is super critical to disassemble your pumps and clean out the sludge that builds up in that cavity and around the impeller rotating element because this reduces the heat transfer, limits water flow, and makes more friction from the hydroscopic forces..like getting your foot stuck in mud and trying to pull it out. No matter what kind of pump you have, you should never suction starve any pump. Its really bad practice to do so, as it can cause cavitation and in extreme cases make water bubbles which can damage the pump and make the pump very inefficient just bad all way around. If you absolutely have to reduce flow, always do so on the discharge, but do not have it so pinched off that there is little to no flow unless you are doing so for short period of time like water change or feeding your fishes.

If you want more info, google search mag drive pumps do's and don'ts and learn more.

As for filtration...nothing beats regular water changes. If you are trying to decide what type of media to use, use mechanical only. Nitrifying bacteria is everywhere in your aquariums from the glass, the décor, the filter media, and filter parts. You need to balance fish load, with food load, and your water change schedule to really decide how big of a filter. I only ever use mechanical media because sponges have just as much surface area as most bio media, and bio media once totally covered is essentially nothing but mechanical media cause there is not surface exchange its plugged so to speak. Chemical media is really up to you and if you want to try to use it to remove other toxins or chemical cause that's what you want. I stay away from it, except in my carbon bottle I use at water changes. Like I said, nothing beats regular routine waterchanges.

AS for how much flow, I did once find in an aquarist book that minimal turnover for most tropical fishes needed only 2X a hour and that was with under gravel filter. If you want to look at flow rate based upon a pump, it really depends on what the oxygen content your fishes need. I've seen plecos live in a tank for a month with no filter at all of any kind on the flipside, I've seen sand dwellers die in just a couple hours.

I believe most aquarist will agree 4-5X pumping turnover is pretty much a standard. Me personally I like as much as possible because I keep Tangs and they require higher O2.

Bottom line, if you want add another filter and it helps you manage your water quality to maintain healthy fishes, then that's what you need be doing. You want to push limits one way or the other, then do so...just try to consider if you want your fishes listless and gulping at the surface or running marathons.. Keep your fishes happy, they deserve it. They didn't ask for this, you did. Take care your fishes!!

[geoff_tropheus]

Heat is a bad thing for mag drive pumps. Loss of flow in an around that rotating element can cause chips and chatter and distortion. Most good manufactures use ceramic shafts and elements, some don't... you want reliability, get the pump that is proper for the setup and application you want.

[black_knight]

Well said! SW enthusiast use flow on live rock to boost their biofiltration. Similarly when you pass water through an undergravel or the rocks and glass on your tank. For my FW tanks , I allow a biofilm on the back glass of my tanks and hardscape to grow and direct flow against them. My water stays clearer and fish do better. I tend to use as much flow as a species can tolerate ( 8-10x). That said, my anabantoids that build bubble nest will not breed with high flow, infact many of them I kept in no filtered tanks with lots of plants ( a natural nutrient sump). Equipment maintance is key. I keep a schedule of pump maintance, usually first weekend of each month, if I'm off.