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Water Agitation - Spray Bar Above or Below

John44

John44

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Joined
1 Jul 2016
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Location
London
So I have spent the morning reading about pH, CO2, circulation etc.
I think I have got the combination about right just one element I need clarity on

Do I have the spray under the water or above - it seems if its above then the splashing (technical term) will negate much of the CO2 being absorbed into the water as most will be lost at the surface

Below the surface seems to be what folk - just wanted to check


Regards
John B
 
John44 said:
So I have spent the morning reading about pH, CO2, circulation etc.
I think I have got the combination about right just one element I need clarity on

Do I have the spray under the water or above - it seems if its above then the splashing (technical term) will negate much of the CO2 being absorbed into the water as most will be lost at the surface

Below the surface seems to be what folk - just wanted to check


Regards
John B
Click to expand...

yeah, surface agitation gasses off the co2 quicker; so trying to minimise it is best (i.e. underwater)
 
so how about the O2, will the plants produce enough for the fish (sorry if its a stupid question)

John B
 
john dory said:
Set it up just below...so that it makes a smooth ripple
Click to expand...
I would be interested in what people consider a smooth ripple....
I am low tech so not worried about CO2 gassing off but I am considering going down the CO2 route.

My current spray bar / pump setup produces this amount of surface agitation which I think is probably too much ???
 
Halve it.

It depends on your stocking though. FTS pls. :p
 
I actually cut the surface agitation down loads after watching


I now have the circulation pump right at the bottom of the tank (in the opposite corner to spray bar) and this seems a bit more balanced. I am not getting dead spots, the fish seem happier and the frogbit is not being destroyed by the huge surface flow. It also seems to have helped with some algae that was starting to appear.

Do people agree with what is in the video???
 
personally I like it. What I have done with my Juwel 190 is to fit 2 spray bars at the front just under the water level so there is very little agitation and then at the front on the left and right added a Hydor Koralia Nano 900 with boost circulation - everything seems to be growing and I cant see any dead spots - i was tempted to put the Nano's on a timer for a few hour each day rather than continuous

John B
 
You will have healthier and longer lived fish when you've got lots of surface agitation. It has its limitations but oxygen is the number one importance in aquariums...from the needs of nitrification, to healthy type of decomposition that produces CO2 instead of other toxic gasses(due to growing different types of bacteria when oxygen levels are limited) to oxygen demand for fish which are always happier in higher oxygen conditions. Surface agitation in nature(think winds and flow of rivers) are the only means of distributing oxygen down to the bottom...Still water lakes, pools, etc... are death traps for fish and only air breathing fish survive it longer term...If this is a low tech, up the surface movement....keep it the way it is on your video above, especially if there are no enough fast growing underwater plants to produce additional oxygen....Also, in a low tech tank a good surface movement is extremely beneficial, even when it comes to CO2...because you want to provide the conditions for the right type of bacteria(CO2 is also a lot more easily dissolved in water from air than oxygen) which uses oxygen to decompose organics and produce CO2...It's always a win, win situation. If you inject CO2, you can alter tactics...
 
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You know, if you want to experiment...get two shallow glass jars.. Put a bit of organic load like freshly cut grass in both of them to the same amount. Stick an air stone in one and leave the other one as it is...Let them run for a few weeks....if the smell doesn't draw you back earlier....Note how they both develop in time, with extra oxygen and less oxygen...I can almost guarantee you that one will smell like your toilet seat...guess which one..
 
I know I read somewhere that co2 will get to a certain level and more surface agitation won't change it.I get oxygen is critical but is there a point when more agitation won't necessarily mean more oxygen?

The agitation is still reasonable just not as much as before. Will get another video in a minute.

The issue I had with the flow in the previous video was that it had a lot of the fish hiding or staying near the bottom because of the flow. I still have the flow but the circulation pump is now at the bottom of the tank and the fish are actually more active over more of the tank. It also meant I couldn't really keep floating plants as they were getting crushed at the end of the tank.

I was also getting algae as whilst there was lots of agitation and flow at the top of the tank there was not so much at the bottom across the plant (and this also lead to areas where detritus would build up). I guess a second circulation pump would sort that but turn the tank into a vortex :)
 
Quick video showing agitation as it is now. Main difference is the far end of the tank which is far calmer.

The latter part of this video probably shows it better
 
You have to try and see what works for you and the fish best.The effects can only be determined long term..Why not try both ways...There's no need of excessive movement though, a ripple is enough. I am just not keen on the murky water and biofilm visible on the video above..It's just not my thing.

Here is what I aim at roughly. The splashing noise is from one of the outlets being above water but that's because otherwise this filter keeps expelling air due to sitting level with the tank...not for any other reasons..

 
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jameson_uk said:
I actually cut the surface agitation down loads after watching


I now have the circulation pump right at the bottom of the tank (in the opposite corner to spray bar) and this seems a bit more balanced. I am not getting dead spots, the fish seem happier and the frogbit is not being destroyed by the huge surface flow. It also seems to have helped with some algae that was starting to appear.

Do people agree with what is in the video???
Click to expand...


At around 13:45 he says he does have biofilm in tanks he doesn't use surface skimmer....In a well oxygenated tank you don't need a skimmer because you won't see surface biofilm...I get biofilm in unestablished new tanks or problematic tanks...
 
Hi all,
jameson_uk said:
I actually cut the surface agitation down loads after watching
Click to expand...
jameson_uk said:
Do people agree with what is in the video
Click to expand...
I haven't listened to all of it, but I think he is talking sense. One thing with the video is that all the tanks have a reasonable plant mass and the fish look really healthy (although they are a bit fat). He actually has quite a lot of water movement, even though he doesn't have much surface agitation.
sciencefiction said:
and biofilm
Click to expand...
Some surface agitation definitely reduces surface scum.

Linear flow works really well for gas exchange, anything that increases the gas exchange surface works. I have both linear flow and surface agitation, but I have a huge plant mass, so I never get the "washing machine" effect.
jameson_uk said:
I know I read somewhere that co2 will get to a certain level and more surface agitation won't change it.I get oxygen is critical but is there a point when more agitation won't necessarily mean more oxygen?
Click to expand...
The more water turn-over you have the closer you will get to equilibrium values with the atmosphere, for CO2 that is about 0.5ppm when atmospheric CO2 levels are at 400ppm (at 1013mb pressure and 27oC).

We had the gas system (for bunsen burners etc) in the lab. upgraded in the summer and we now have a CO2 sensor fitted to an automatic valve shut-off system. It usually records about 600ppm CO2, although when the lab. is busy it rapidly gets to 1500ppm (at which point you would have an equilibrium value nearer to 1.5ppm).

During the photo-period the water may become saturated with oxygen, and then pearling occurs. The best option for looking at levels of oxygen during a diurnal cycle would be to look at pH, which will change as the CO2/O2 ratio changes. It won't give you an absolute measure of dissolved oxygen, or be applicable to another tank (too many variables, dKH, tank architecture etc), but you could measure pH with different flow patterns and see what happens.

This was done in this thread <"Maxing CO2 in low tech....">

5cxa-jpg.25693.jpg


cheers Darrel
 
Hi all,
sciencefiction said:
At around 13:45 he says he does have biofilm in tanks he doesn't use surface skimmer....In a well oxygenated tank you don't need a skimmer because you won't see surface biofilm...I get biofilm in unestablished new tanks or problematic tanks...
Click to expand...
Just watched that bit. I think that is because he has a higher fish load than we would normally have, and that he definitely feed his plants more than I do (although that could be a combination of the more fish and "agriculturally improved" tap water).

cheers Darrel
 
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