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High water turnover - discuss :)

Matt Holbrook-Bull

Matt Holbrook-Bull

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Due to this subject cropping up on lots of other threads I thought Id start a proper thread for it, so we can hammer it out!! *nudge Clive* 😀

The subject is filtration and high turnover..

Back in the old days a few years ago, Tom Barr was advising low turnover due to the fact that ferts and CO2 can get filtered/rattled out of the water column, obviously causing expense and/or problems.. this opinion seems to have changed over the time as the hobby has progressed and we've all learned more about how things work.

My point is this... Due to the obvious need for good circulation to provide ferts/co2 to any plant in the tank, a high flow rate is obviously desirable. But, surely the answer isnt to increase the size of your filter.. surely its better to add power heads to the tank to get the same effect? I realise these are ugly things, but they can be hidden almost anywhere with decent scaping.

Anyway.. thoughts and different experiences most welcome 🙂
 
Hiya Matt,
Yeah, powerheads can help quite a bit - there's no denying it whatsoever, but haven't you noticed the trend towards removing things from the tank and to reduce clutter in the tank - inline heaters, inline diffusers, glass pipework etc? This aesthetic movement is away from clunkiness and towards a more streamlined and minimalist look.

Once you determine how much extra circulation you need then you have to pick the right size powerhead, and that can be unsightly. Remember we talked about how to achieve various flow patterns as well? It isn't just the added flow throughput but the circulation lines to eliminate dead spots, so this means you have to really get creative about how and where you position the pumps. That means that now your aquascaping has to encompass the geometric solution of fluid dynamics as well as art. No thanks. :shock: Have you seen Barrs latest 180G effort? It looks fantastic until your eyes wonder over to the rocket propelled grenade launcher on the left, ugh...http://www.barrreport.com/general-plant ... ar-13.html

That does illustrate however how committed he is to flow and I believe if you read through the thread his total flow is a massive 4000 LPH. The larger the tank the more committed you need to be about flow. CO2 becomes more problematic as tank size increases but is important in all sizes.

The other thing to consider is that the bigger the pump rating of a filter the more filtration you have. More biomedia means more bacteria and that means better NH4 control. We should be committed to getting NH4 outta there as quickly as possible especially if the tank is highly lit.

I've use lower flow, powerhead augmentation and bigger filters and the hands down best solution from an algae, plant growth as well as from an aesthetics standpoint I've found is massive filtration. Remember that my tank is lit by 1/2 kilowatt of CF T5 with reflectors and sits in a conservatory open to sunlight. It is extremely well lit. The difference in algal blooms was immediate as soon as I upgraded the filtration.

Now does this mean that you won't get algae if you have massive filtration? Hardly - a high filtered tank is subject to the same rules, so that poor dosing or too much light or poor CO2 will cause trouble. Does that mean you can't be successful with lower flow? No, not at all, many do. What we're saying is that massive filtration is your ally. It means that if you do suffer an algae attack then it's loads easier to get rid of when the throughput is higher because you have a bigger bacterial army as well as better nutrient delivery. What it means is that you can upgrade your lighting with less trepidation because CO2 delivery is more efficient with higher flow. You can also overstock more with less fear - so there are lots of benefits of higher filtration besides the added flow. George is even more fanatic than I am. I think he follows the 20X rule... :shock:

Cheers,
 
Im trying to talk myself OUT of buying more stuff!! :lol: Your not helping!! :lol:

Yes, the aesthetic angle is a really deal breaker.. while I dont like to be led by the trends of the world there's no doubt that a tank devoid of any hardware is a more beautiful one.

Flow seems to be much more of an issue the larger you get.. back when I had a 140, it was no issue to get the flow I needed, even though it was long and narrow, not long and fat like this 235 is. Today Ive sat and watched the tank clearing after its rescape (pictures to come I promise!) which has given me a chance to closely observe the flow patterns in the tank. Its rare you have the turbidity to see it clearly enough, and there are dead spots.. even with the spareness of a newly planted scape.

Ive moved the power head around to point the other way and now I have a nice 'sway' on everything.. but I worry as things get bigger that that will reduce.

And yes, boy does Gerryd have some serious flow going on in that tank.. its a wonder he keeps anything rooted!! To me thats overkill and no mistake.

I wont have the wedge for a new filter until end of the month anyway, so thatll give me a chance to observe the growth differences now Im using AS before I inevitably fork out another £150 on this pile of water in my living room!

Still be interested in anyone elses opinions though as a matter of discussion, especially your's George and Dan.
 
Also too add, why spend moner on just extra flow when you can have filtration aswell? Say you get a cheap powerhead like the maxi-jet 400 http://www.warehouse-aquatics.co.uk/max ... -145-p.asp for £13, why not spend this on flitration? If we look at the fluval 05 series, this £10 can get you the next size filter up which means more filtration and flow (100l)
 
aaronnorth said:
Also too add, why spend moner on just extra flow when you can have filtration aswell? Say you get a cheap powerhead like the maxi-jet 400 http://www.warehouse-aquatics.co.uk/max ... -145-p.asp for £13, why not spend this on flitration? If we look at the fluval 05 series, this £10 can get you the next size filter up which means more filtration and flow.
Click to expand...

youre not helping either!!!! 😳 :lol:
 
If you can track it down Tom posted a series of photos showing the same stretch of river in high to low levels of flow, even in nature low flow = algae, and you've guessed it plants out in the fast flowing area, devoid of any algae.
I'm an advocate of what was previously considered over filtering but there has to be a stand point where there is simply too large a filter.
I'm about to set up a fx5 for my 15gallon tank (anyone know where I can get cheap filter media? pm me), it can go 2 ways, disaster or success I think the benefits of high flow are clear to be seen especially when you consider that you will have items inline that will limit the flow anyway.
 
Hi Matt

For the record, I think the filtration, flow and circulation 'new-school thinking' is one of the biggest developments in the hi-tech planted tank hobby, behind CO2.

Bigger is better, simple as that.

20x turnover rule is good for me for smaller tanks under 100 litre. 10x for bigger tanks. Jeremy Gay and I joked about this actually. One should not go for the 10x turnover rule, but the 10x rated rule i.e. a filter rated for a 1000 litre tank should be used for a 100 litre tank.

I think it's also important to combine the good flow and circulation with good biological filtration to further help minimise potential algae isssues. So I'd always opt for bigger and better filters, over filter+powerhead.

BTW I've had good results with less i.e. Juwel internal filter. But this was low light and I highly suspect that with high lighting etc. then it wouldn't be enough. And that's a very important point. In lower lit tanks, the importance of getting all the CO2 etc. around the tank isn't as important.

So Matt, what would I do in your tank? Probably have 2x big externals with a combined rated flow of around 2400+lph.

JAmesM said:
I've still got a copy of PFK where they warn higher turn over causes algae :lol:
Click to expand...
Those were the days. Well, the days before some jumped-up, over-enthusiastic geek called George Farmer came along and preached about the 'dark arts' of NPK dosing etc.
 
Agree totally with Clive & George the more circulation the better.
I was skeptical when i first read some of the posts by Clive.
I was having trouble dealing with GSA at the time and decided to give it a go. I added a second Tetratec 1200 to my 180l tank (overkill i know). But the change in the tank within 2 weeks of adding the extra filter was astounding. GSA gone, foreground plants really took off, this was one area i had really struggled in. The stems and crypts in the tank look healthier and grow faster than before.
I changed nothing except the extra filter, No changes to co2 or dosing. Water never been as clear either.
Though it did take a day or two for the fish to peel themselves off the back wall.
 
I like the idea of overfiltering, not just because of the additional redundancy you could build into your fishkeeping by having an extra filter (if you choose this method) but because I do worry about not being able to rely on the flow of water around the tank.

On my 200l, I have to date run one 2026 (950lph if you believe Eheim) and have just bought a new 2026 to run on the other side of the tank. It was only through some of the filtering discussions on this site, that my eyes were opened to the differences between the advertised flow rate and the actual flow rate with filter media/head height included. I realise that if one assumes that you may only achieve half of the advertised flow rate, I'm still only doing 5x turnover by running both, then at the least I will have achieved a better flow of water, nutrients and CO2 through the tank and increased my biological/mechanical filtration whilst we're at it.

My only real concern is the fish. My fish in the little tank are much more subdued with a stronger filter and I'm picking up some fish at the weekend who prefer slower flow so I will have to see how it goes!

On a side (and slightly smug) note, my second 2026 was bought BNIB as a second from Zooplus for £37.50 plus postage.
 
Ehiem fx5's are HUGE, and as far as I can tell they'd be perfect for your set up.
 
Matt Holbrook-Bull said:
so.. next question.. £150, which one? I can get an FX5 for bit less than that.. but the big Eheims are going over.. advice please!
Click to expand...

Just a thought... You could buy two Tetratec 1200's for £150 :!: or just one if you want to save some money 😉
I bought one a couple of months ago and the only downside is that it is not silent. Although saying that I am now used to the hum and don't hear it anymore.
 
Well I'll stick up for the powerheads here. The aesthetics are the problem, but I don't mind that as mine is tucked at the rear top corner.

However I wouldn't use a normal powerhead but one of the flow pumps. They have much broader flow patterns that move a lot of water in a more gentle way while keeping detritus and CO2 bubbles in suspension long enough for the filter to get the dirt or for the CO2 mist to dissolve. Mine also doesn't blast my fish or shrimps around the tank too much; in fact the Blueyes love playing in the flow.

As to Biological filtration, the limiting factor on bacterial growth is almost certainly nutrients (in this case ammonia) in well filtered tanks, not the area of biological media! If you have the same bioload and add twice as much media the competition in the biofilm at any one point may reduce allowing a wider range of microbiological fauna, but they won't start assimilating more ammonia as there won't be any more to feed any more bacteria. I think the simple fact is that larger filters may improve mechanical filtration but there is a limit to biological performance based on the nutrients supplied. Using a media that promotes a wider range of fauna by giving a roughened, variable surface will improve filtration by allowing better establishment of the biofilm. Once a good biofilm is established then it is very resilient too.

I can't see a mechanism where it would increase the rate of uptake of Ammonia, except for the fact that the improved turnover will get the ammonia into the filter more rapidly. I can't see it making that much difference to be honest.
 
I added a powerhead to my tank and its doing the trick, its really a small internal filter which as a sponge and all, works pretty well for my size tank and since then I haven't had any more problems, things just grow like weeds. Its well hidden behind the plants and you can't really see it unless you go looking for it as you probably can see on the photos from my tank.
I will replace my external eventually but I will wait until it breaks or something like that.
 
Ed brings up some interesting ideas on the biological side of things which I totally agree with. Going against what is commonly suggested I think that adding 2 large filters on a tank is just a tad overkill. A single good filter will more than adequately deal with the tiny amounts on ammonia that are created in planted tanks. They are designed with much heavier bioloads in mind. Have a sudden ammonia spike and I would think that a single filter would probably deal with it very nearly as quick or as quick as 2 or more filters.

IMHO stable low levels of ammonia are no big deal and don't cause algae as is commonly suggested. Many people dose ammonia products daily with great success. I've dosed urea daily for 2 months and noticed no algae whatsoever. Those of you who dose Tropica Plant Nutrition Plus are dosing ammonium nitrate. All the other commercial nitrogen products that I know of also contain urea or ammonia compounds.

Flow is a different thing and is very important in a heavily dosed, high light and high CO2 tank. Adding more filters to add flow is fine or you can save your money and use pumps.

I'm sure many will probably disagree with me.
James
 
James/Ed,
I've thought about your points and while they do seem reasonable, they bring up more questions than they answer. Now, remember my arguments are based on premise that NH4 + light cause algae. If you don't buy that premise then the arguments are not valid.

James, I remember that urea experiment you did and Barr brought up the strong possibility that the filter and sediment bacteria were reducing the ammonia in the urea via enzymatic action of urease. That would mean the bacterial reaction to NH4 is very quick, and that suppression of NH4 spikes are attributed to rapid nitrification.

I guess I also disagree with the assessment that "...tiny amounts of ammonia..." are produced in a planted tank. I would argue that the ammonia production is high and is constant simply by virtue of metabolism. Just consider the amount of ammonia generated during a tank cycling. That ammonia production rate never stops, and in fact it accelerates when we add plants and animals and food. It's just that we measure a low concentration level because the NH4/NO2 is being processed. Barr brought up the point in that thread that if you thought ammonia production in a tank was low, all you need do is to turn off your filter for a while and see the results.

All we have to do is to look at our empirical evidence. How many reports are there of algal blooms in a planted tank? Algae has become almost a central theme. A contributing factor? Ammonia production not attenuated by the available bacterial colonies. So what you say is true, that low stable levels of ammonia keep the blooms at bay but how does one achieve low stable levels? Its certainly not stable when one feeds the fish for example. Metabolic rates and organic waste decay are not really all that stable as the plants grow or are trimmed, or when water is changed. I would argue that an aquarium is the least stable aquatic environment known to man. If sintered glass media or sponges function as we think they do, by making space available for hosting bacteria, then more space means that a rise in NH4 allows these germs to increase their population more easily. If less space is available would this not affect the rate of bacterial population increase necessary to consume an NH4 spike?

We observe that detritus and organic waste buildup stifle a filter by blocking the pores of the media reducing the bacterial population. Detritus sitting in the filter breaks down into ammonia which fails to be processed by the colony. The result is often BGA if filter maintenance is not performed. It seems obvious to me that if you have more filter capacity to begin with the likelihood of this condition is reduced. Maintenance is still required, obviously but you have more biomedia and space to begin with so the effect is lessened and your margin of error is widened.

I also don't buy the assumption that bacterial populations are necessarily limited by NH4 availability. Of course this could be the case under certain conditions but we really haven't measured populations versus NH4 concentration so this would be speculative. Also it's not certain that all the NH4 in a volume of water is removed during a single pass though the filter. So if I connect two filters in series this assumption would mean that bacteria colonies would be established in the first filter and not the second. Clearly, while the available space is not completely filled in both filters the available space represents a potential that affects the speed at which the population can increase. This population agility allows absorption of ammonia spikes which occur constantly.

Again, I refer to the urea thread in which Barr referenced a list of K.R. Reddy journals. Further investigation reveals that bacteria, like plants and animals require more than just Nitrogen to prosper. They require Carbon and Phosphorus as well as other ingredients. So a bacterial population could easily be limited by the availability of other nutrients. Like Nitrogen the other nutrients must be in the right form for them to digest. Some bacterial species can obtain their nutrients in a variety of forms (i.e. organic and/or inorganic) or they can use substitute elements for their biological processes, such as Sulfur in lieu of Oxygen. Other species are less agile and suffer die off if their specific needs aren't met.

We all agree that flow is definitely King, but I view the extra filtration capacity as a "shock absorber" that processes ammonia spikes which helps to suppress algal blooms. It is difficult to quantify though how much of one's success is due to the extra flow versus the extra filtration capacity. :?

Cheers,
 
Yes, but you'll never see that flow rate in real life, especially if you fill it with biomedia.

I should add that the only real thing I have against powerheads is their lack of aesthetics. As mentioned, they are a much cheaper alternative and if you don't mind the looks, or if you have a clever way to hide them then they give you a lot of flexibility as you can point them in whatever desired direction. In the final analysis if economics forces you to choose between healthy plants with ugly thunderball jet packs versus less healthy plants with clean tank lines, well, go for the jet pack... 8)

Cheers,
 
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