Is too much flow bad?

kirk

Member
Joined
24 Dec 2012
Messages
1,659
Location
tewkesbury
Interesting question about too much flow. I been wondering this since set up as growth is very slow.

I am using the same filter and korilina on this 60 ltr that I was using on our 120ltr.

If I was using cat litter it would be like a snow globe.:D
e19090317717beec8ba2450ba4cabf4f.jpg
 

Edvet

Global Moderator
Staff member
Joined
15 Aug 2013
Messages
5,149
Location
Lelystad, Netherlands
I always take clues from Flowgrow or Kasselman, f.i. on Staurogyne they say: "The aquarium population of this species originates from Rio Cristalino in the Brazilian federal state Mato Grosso. The plant were found growing on and between rocks on the bank of the fast-flowing river, mainly above the waterline, and in full sun." They should be able to cope with flow, if they have plenty roots.
On the other hand most popular aquariumplants (from commercial growers) usually grow well emersed,,hence are more bogplants then real waterplants.
 

Jose

Member
Joined
9 Oct 2014
Messages
1,369
Location
Salisbury
I think as has been stated before that: as long as plants are not being lifted from soil or being moved around violently then flow isnt excessive. Maybe some mosses might not like higher current but thats about it. Also if a plant is being pushed around violently this doesnt necessarily mean that you have too much flow, it can also bee that you have bad flow distribution in the tank. But yes I still think in few cases flow can be excessive, specially from powerheads.
 

Ryan Thang To

Member
Joined
18 Jul 2013
Messages
1,562
Location
London. milton keynes
When i had my 90cm tank planted with glosso it only grew upwards. I had a aps 2000l/h filter and 2 1600l/h hydor power head on each side. This was my first high tech and i was told it that its all about balance with co2 light and good flow. I was convince flow wasn't enough so got 2 power head. Here some pictures of my set up and what a change after lan holdich a ukaps member mention about my tank has too much flow.
AI1_Uh_EU.jpg

v_Uqjp_QL.jpg

A few days after removing the power head
e18_HMI8.jpg

A week in and glosso is spread finally
wyi8_CAP.jpg

A whole month carpet nealy complete
g_Te_H3h_A.jpg
 

Andy Thurston

Member
Joined
16 Apr 2013
Messages
2,812
I've trimmed mine already to stop it taking over the tank, monte carlo is going crazy too. I'll try get some pics for the journal when the co2 goes off
 

Iain Sutherland

Global Moderator
Staff member
Joined
7 Jul 2011
Messages
3,681
Location
Cambridge
high flow can reduce growth in my experience. Particularly in my 60 i find the slowest area to carpet or plants to flourish is around the diffusor where flow is highest. Not sure why? Possibly the flow is so strong the co2 is just whipping by? Reduce the flow and those plants perk up. Its a fine balance... as we speak my reinekii mini around the diffusor that was invitro and planted last week is shedding a few leaves but the rest of it is doing just fine elsewhere. I try to think of it as turn over not flow... high turn over good - high flow not so great normally.
 
Joined
26 Feb 2013
Messages
3,349
Ha, ha Edvert....:D

They look like they have a CO2 problem lol :rolleyes: And the water needs a bit of purigen to clear up the floating matter.....
 

Jaap

Member
Joined
30 Sep 2011
Messages
1,070
Location
Nicosia
Although I like what Jordi said, I put my two cents in this discussion.
According to one study there can definitely be such a thing as too much CO2, as in this study after the CO2 concentration exceeded 40 ppm, some plants begin to suffer, and their growth rate degraded a lot. The author of this study concluded that this high CO2 concentration may "poison" some plants.

As to the flow, we all probably know that the higher the flow the thinner the boundary layer and the better the nutrient uptake rate. So higher flow means better growth for most aquatic plants. I would add that as long as the plant is able to control the position of its leaves toward the light source, the flow is OK. So the flow is too high whenever the leaves cannot turn toward the light anymore, and are just carried by the strong flow which they are not able to resist. So plants need for their leaves to be directed toward the light, so if the flow is too high, the leaves are not able to collect photons efficiently enough, and they begin to be stressed. (Vallisneria is maybe an exception, as its leaves are long and can float on the surface, so even in the very strong flow it can collect light quite efficiently.)
If it "poisons" plants, however fish seems to be fine, is there a chance that useful bacteria get "poisoned" as well which in consequence causes diatoms?

Also can diatoms be produced without the presence of fish and their waste products?

Thanks
 

Jose

Member
Joined
9 Oct 2014
Messages
1,369
Location
Salisbury
If it "poisons" plants, however fish seems to be fine, is there a chance that useful bacteria get "poisoned" as well which in consequence causes diatoms?
I highly doubt it. What happens in tanks where people keep very high co2 levels and no fish. They wouldnt get rid of diatoms yet most dont have it.
Also can diatoms be produced without the presence of fish and their waste products?
Yes for sure. Fish arent actually the main source of waste in many high tech tanks. Its plants.

Also I would just like to say one thing. The link Ive read for the study where the conclusion made by some is: high co2 (over 40ppm) can kill plants has to be taken with a pinch of salt. This is not totally true/ not always. What they say is that for a certain weed at a pH under 7 (If I recall correctly) the higher co2 levels can kill the plant, but not for higher pHs. This is a very specific situation and shouldnt be extrapolated to saying that 40 ppm of co2 can kill most of our plants. This doesnt happen and the opposite does. The more co2 the better most plants grow, specially the harder ones.
 
M

Marcel G

Guest
Jose, no one (or to be specific: not me nor the author of the study) said that higher CO2 concentration will kill the plants. What the author said is that the concentration of 1 mM CO2 (= 44 ppm) caused rapid decrease of growth in the studied plants. When I spoke personally with the author she told me that she explains it to herself as a kind of "poisoning effect" (as if too much CO2 somehow "poisoned" the plants). Also, no one says that all plant species react to elevated CO2 levels in the same way. But for sure there are at least some plants which don't prefer high CO2 levels. Each plant has its optimal growth under different conditions. What I wanted to say is that we should be aware of it, and don't repeat blindly that we need 40 ppm of CO2 or even more. Also the author of this study concluded that the difference in growth was definitely caused by the elevated levels of free CO2 and not by the pH. I have the whole work in Czech language (the article in English is just abbreviated version). Also I'm in contact with the scientist (author of this study).

What I can confirm from my own experience is that diatoms really don't need too much organic wastes to prosper. Once I had a test tank where I had about 150 ppm NO3 and quite high levels of other nutrients leaching from the substrate bottom layer packed with a fertilizer (you can look at it here => Test #3). I did some laboratory analysis of my water, and there were nearly no organics in it, but high level of inorganic nutrients. Also I did not used any CO2 in this tank, just Excel. The tank was under "high light" (100 µmol PAR). All other algae as well as cyanobacteria just died after two weeks of bloom. The pH went down to 5. The redox values were extra high (above +500 mV), and were constantly increasing. The only visible organism that survived in this hostile environment were diatoms. I suspect that even the useful bacteria had to stop working in such an environment. Diatoms seems to be immortal.
 
Last edited by a moderator:

Paulo Soares

Member
Joined
6 Nov 2014
Messages
603
Each tank is a tank.. each experience is a experience.. mother nature is not an exactly formula.

I notice that in my tank the area with less flow is the one under the outflow and plants there doesn´t grow so fast as all others..
So according to this i would problaby say that less flow equal to less growth ins´t that so?.

But than again we would have to measure all variables mentioned by "Parotet".

Concerning the CO2:
In my opinion for what i was able to observe in my tank along the time, high levels of Co2 does harm the plants.

Without changing any other parameter i only downgrade the Co2 and notice plants to be having a more colourful aspect and robust stalk cause they are not growing so fast.
There was a more sustainable growth. If you increase to much CO2 (macro nutrient) is just like if you do ignition on an engine and pump the gas without letting the engine to warm up and lubrificate all engine parts so that you could take an 100% profit from it. Get the Picture?

You can have the light you want or uptake Ei fert as much as you like and so on but it all leads to Co2 as this is the ignition for plants to assimilate the rest.

So here yes.. i assume CO2 as the major factor for a sustainable growth.

And finnaly.. doing the mental exercise in inverse we came to the the initial issue: The flow!

In order to have a very good Co2 dissolution in the tank, yes you´ll need good flow! Not faster.. Good flow is: efective/eficient/ and this doesn´t mean outflow velocity ou filter pump capacity liter /hour.

Another thing, you´ll probably also need to figure out (testing) what hardware positioning gives the best result. And for measure that is not a question of days but weeks.. be patient.
Assembling and being a day watchfull hobbiest to see improvements or not. ;)

Notice: Seeing bubbles of CO2 going around the tank is not a good guide to assume a good efective flow or CO2 dissolution as so many people think it is. If you see to much bubbles maybe you should consider changing your Difuser also.

Regards.
 
Top