Emil.
Member
Practicality aside, would air tight hood with CO2 only above the water surface work for CO2 distribution? Could the surface agitation in this scenario be delivering enough CO2 to the water column? 🤔
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Does good 'flow and distribution' always require high current?
- Thread starter Wookii
- Start date
It's an interesting idea, but I think it might cause more issues than it solves. You still have to get the CO2 from the surface to the bottom of the tank, so you still have to implement strong flow/water velocity which is what we're trying to avoid in this design goal - otherwise I would assume you'd just end up with a thin layer of water at the top of the tank in equilibrium with the CO2 enriched air gap.
I also suspect that pumping the surface air gap with lots of CO2 would push out most of the oxygen, so you could end up with an issue of insufficient oxygen in the water column also.
I think an external reactor is always going to be the best option for efficient CO2 delivery, but the question is then how to deliver that CO2 enriched water to all the corners of the aquarium most efficiently, and with minimum velocity.
So like a CO2 reactor - yes, but we also need O2 esp at night, so best to use a CO2 reactor then plants/livestock still get CO2 at night, plus gassing off at the waters surface helps maintain stable [CO2] and prevents the [CO2] from getting too high. But as @Wookii points out we still need good flow 'Flow is King' in the supply of CO2 to our plants esp in tanks with high [CO2]
Im gonna bump this thread a bit and ask you @Wookii what outlet/intake setup have you ended up with?
Ive been generally unhappy with, fidgeting and experimenting a lot with my filter outlet, most of my fish seem to enjoy the slower parts of the tank and I would like the same thing as was the goal in this thread.
Having a spray bar along the entire back of the tank served the plants well, but gives the fish some confusing swimming habits.
Instead of swimming against the flow horizontally like in a river or a small stream, they swim against it vertically and it looks kinda strange. I dont know if it bothers them though.
Now I have the spray bar placed along the left side wall, with the intake in the back left. I quite like it, aside from the slightly unnatural zone in the midwater where the left leaving and right returning currents cancel each other out, it feels a bit more natural.
The fish swim horizontally instead of surfing up and down the front glass, and I feel like it looks more comfortable for them.
However I still think I may have too much velocity as my boraras swim against the glass right below the spray bar, and my pygmy corys always congregate in the area right in front of the filter intake. Its also kinda annoying to feed as the food gets blown away so easily.
I want to make a custom spraybar for my tank width like I did for the back wall, but this time aiming for lower velocity. Im just waiting for some materials.
But I have also thought about getting flow going only one way, ie from the left to the right and not back again. This would not create the strange zone in the midwater.
My immediate thoughts are that the bottom left (below spraybar) and front right (opposite of intake) would be spots with less flow.
I also worry that the velocity from the spray bar might have the water hit the right side glass at such a speed that it bounces off and starts going back left again, sort of missing the intake. But I have not tested this in practice. It may be possible to avoid this when designing the spraybar.
Who could have thought one could spend so much time thinking about some bits of plastic.
Ive been generally unhappy with, fidgeting and experimenting a lot with my filter outlet, most of my fish seem to enjoy the slower parts of the tank and I would like the same thing as was the goal in this thread.
Having a spray bar along the entire back of the tank served the plants well, but gives the fish some confusing swimming habits.
Instead of swimming against the flow horizontally like in a river or a small stream, they swim against it vertically and it looks kinda strange. I dont know if it bothers them though.
Now I have the spray bar placed along the left side wall, with the intake in the back left. I quite like it, aside from the slightly unnatural zone in the midwater where the left leaving and right returning currents cancel each other out, it feels a bit more natural.
The fish swim horizontally instead of surfing up and down the front glass, and I feel like it looks more comfortable for them.
However I still think I may have too much velocity as my boraras swim against the glass right below the spray bar, and my pygmy corys always congregate in the area right in front of the filter intake. Its also kinda annoying to feed as the food gets blown away so easily.
I want to make a custom spraybar for my tank width like I did for the back wall, but this time aiming for lower velocity. Im just waiting for some materials.
But I have also thought about getting flow going only one way, ie from the left to the right and not back again. This would not create the strange zone in the midwater.
My immediate thoughts are that the bottom left (below spraybar) and front right (opposite of intake) would be spots with less flow.
I also worry that the velocity from the spray bar might have the water hit the right side glass at such a speed that it bounces off and starts going back left again, sort of missing the intake. But I have not tested this in practice. It may be possible to avoid this when designing the spraybar.
Who could have thought one could spend so much time thinking about some bits of plastic.
What do you mean?
Just suggesting if the OP likes the behaviours of fish etc in minimal flow, this could be a worthwhile avenue...
It doesn't however, answer the original question, I'll concede.
I didnt think Walstad had much to do with amounts of flow to be honest. I know at first she said no flow, but then later revised her method to include a small circulation pump, as no water movement was a bad idea. Thats the short of it as far as I understand.
Well you probably dont need anything like that amount of flow in a low tech tank although in 250lt your filter would be more suited .
A full lenth spray bar across the back is probably the most gentle form of getting an even flow, ajusting the hole size and number will adjust the the flow effect and reduce any jetting there might be.
I am pleased you are concerned about you fish and excess flow might be an issue for some lake dwelling fish but adding some rocks or wood should offer calm areas.
I can recall a controversial chap on this form a few years back who insisted on using an amazing 50x flow rate as he considered this more natural for river dwelling fish (piranhas i think) .
A full lenth spray bar across the back is probably the most gentle form of getting an even flow, ajusting the hole size and number will adjust the the flow effect and reduce any jetting there might be.
I am pleased you are concerned about you fish and excess flow might be an issue for some lake dwelling fish but adding some rocks or wood should offer calm areas.
I can recall a controversial chap on this form a few years back who insisted on using an amazing 50x flow rate as he considered this more natural for river dwelling fish (piranhas i think) .
Hi mate,
No this thread was thinking about flow designs for my 1500 tank which I have had to put on hold as SWMBO wants to move house in the next couple of years, so I may as well wait rather than trying to move a filled tank.
I came to the general (but unproven) conclusion in my own mind that, in order to get good distribution (given it would be a CO2 injected tank) whilst reducing water velocity, I would need to trade velocity for volume.
What I mean by that, is imagine a slow flowing river. Say it’s going really slow, say 1m movement every 10 seconds. The water velocity is very slow, but volume of water being displaced is very high. So that is the principle I was going to try and adopt, distribution by displacement using a high volume of slow moving water.
Obviously we can’t easily replicate that kind of river movement in an aquarium exactly (it’d be about 72,000 litre per hour turnover on a 300 litre 1500mm tank, if my calculations are correct) but I was planning on doing something similar.
My plan was to use a acrylic pipe as a spray bar at one end - similar to what you are doing now - but with the exit point to the sump at the other end so flow is in a linear direction. The spray pipe would be around 30-50mm OD, with a variety of large holes cut in it - I planned to have the spray pipe threaded to screw onto the pump inlet bulkhead in the tank, so it could easily be replaced and I could try different patterns and designs.
I then planned to use one (or maybe two) Ecotech Marine Vectra L2 pump(s), rated at 11,500 lph, to push the water through it. I would enlarge to holes sufficiently such that the velocity through them is as gentle as possible.
The basic principle in my mind was to dump 10,000-20,000 litres per hour in one end of the tank, so it displaces all the water all the way down the tank, but in a way that has low water velocity.
Obvious this is all just planning stage stuff - it might not be physically possible - the sump might not be able to handle that flow, I might not be able to sufficiently reduce the velocity of the water exiting the spray tube, the volume turnover might still not be enough to avoid dead spots and achieve complete regular displacement of all the water in every area of the tank. Lots on unknowns but I plan to give it a through go and test one day.
Paul Kettless
Member
For once this is a subject that I may actually be able to have some input with. After keeping reef tanks for many years, eliminating dead spots, distributing nutrients via dosing and getting gentle flow (especially for soft corals, they would close up if the flow was too strong) we would use a combination of a sump tank, and wavemakers on a controller.
The weir generally would be in the middle of the tank and not a corner, I outlet and 2 intakes with one pointed left and the other pointed right giving two circular motions. I found it impossible to eliminate dead spots in a marine tank with such volumes of live rock, unless you used wavemakers. The really serious guys would drill there tanks multiple times all over it with directional bulkeads and use a huge water pump to split the flow equally. This off course involves lots of pipework and a poweful non emersed pump. It mentioned previously in this thread by someone, and I cant remember who sorry! That they use 2 powerheads on a controller and vary the speed of the pumps at different times of the day.
This was exactly the process that 90-95 percent of reefkeepers would use to distribute good flow (not fast unless you wanted that off course) The wavemakers I had were x 4 and the program would alternate the pumps at various intervals, and power. This would vary during the day/night, at some points the pumps may only be having 2 working at 10 percent. I would have them gentle over the early mornings, ramped accross the main lighting period and then reduced again considerablyat night. You would definitely see a difference in the fauna behaviour when the flow was less, well apart fron the tangs they would sulk.
Asthetically not the most attractive things, and the ones that are demand a heavy cost. Although It seems the issue we have here is that Aquascapers want clean, almost clinical lines in ther tanks and rightly so for obvious reasons, but sometimes to achieve a goal a compromise has to be made. Im amazed that more aquascapers dont use wavemakers/powerheads more in there aquariums. After all "wavemaker" sales pitch is just a pump that is fully controllable in speed, flow just moves water at whatever rate/direction you want it to. It worth mentioning here, that I am not talking about high flow rates here, but the flow that youn want to achieve.
Edited typos#
The weir generally would be in the middle of the tank and not a corner, I outlet and 2 intakes with one pointed left and the other pointed right giving two circular motions. I found it impossible to eliminate dead spots in a marine tank with such volumes of live rock, unless you used wavemakers. The really serious guys would drill there tanks multiple times all over it with directional bulkeads and use a huge water pump to split the flow equally. This off course involves lots of pipework and a poweful non emersed pump. It mentioned previously in this thread by someone, and I cant remember who sorry! That they use 2 powerheads on a controller and vary the speed of the pumps at different times of the day.
This was exactly the process that 90-95 percent of reefkeepers would use to distribute good flow (not fast unless you wanted that off course) The wavemakers I had were x 4 and the program would alternate the pumps at various intervals, and power. This would vary during the day/night, at some points the pumps may only be having 2 working at 10 percent. I would have them gentle over the early mornings, ramped accross the main lighting period and then reduced again considerablyat night. You would definitely see a difference in the fauna behaviour when the flow was less, well apart fron the tangs they would sulk.
Asthetically not the most attractive things, and the ones that are demand a heavy cost. Although It seems the issue we have here is that Aquascapers want clean, almost clinical lines in ther tanks and rightly so for obvious reasons, but sometimes to achieve a goal a compromise has to be made. Im amazed that more aquascapers dont use wavemakers/powerheads more in there aquariums. After all "wavemaker" sales pitch is just a pump that is fully controllable in speed, flow just moves water at whatever rate/direction you want it to. It worth mentioning here, that I am not talking about high flow rates here, but the flow that youn want to achieve.
Edited typos#
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Having had twin spraybars in my 500l at either end of tank I can feel your pain, and maintenance was a real PITA. Then to having twin Maxspect 330 with controller and 9000l/h output life as become so easy.
It does mean when gyres on full I have a theoretical output of 18000l/h plus the Fluval FX6 so about x36 to x40. Fish have to choose their swim areas to suit. I was also concerd that going from zero to full power would send a wave over the end of tank, no such issues as you can control how fast it get to full speed. Only use full power when doing maintenance, have them changing every 5mins from one @ 50% and other @20% and hourly 5mins worth of 1min @70% and 20%, run this schedule form CO2 on till lights off. At night I just have one on at a time for about an hour, as it allows leaves to fall off them and cleanup crew to clean them
Paul Kettless
Member
Very good point and I would also do this on a water change day for a short period just to get as much detritus in the water column for maintenance and water change.
Yes thats what I do and turkey blast the substrate then just clean the filter media after an hour or so after a WC
Ah yeah that makes sense. Those sure are some dizzying numbers. It will be interesting to read if/when you ever end up testing this. Hope you will share it with the forum 😀
I swapped out the spraybar I had in for one with even bigger holes and so far the results are positive with the fish. They are a bit more all over the place now. So that makes me confident this is something I can do to increase their comfort, and not something ive just been imagining. It may have slightly too many holes this one, but again a custom one I can make perfectly tuned. Obviously perfect in this sense is a totally nebulous point of compromise between the fish and the plants. I keep plants for the benefit of the fish, which makes things slightly easier.
The gyre pumps sure are innovative, if I ever make a river tank I will probably use them for flow.
I suspect they would be overkill for this tank though, it feels a little bit like buying a racecar that you use only for dropping grandma off to bingo night.
How are the gyre pumps protected, are they like most wavemakers that they have a guard around them, but the guard is dimensioned mostly for larger fish?
Would covering them in mesh/netting impair their function?
I have itsy bitsy fish and a lot of fry so I have to safeguard everything with very fine mesh, otherwise things get tragic. Its a pain in the a 😅
Whats the top speed of the car you drive and how often you you drive it that fast ? Its the same with the gyres. As for the fish shrimp well I have a rule of no fish bigger than 3cm when fully grow and have had had no known issues, I sure some young shrimp have not survived the vertex of death whilst other baby shrimp just get eaten by the fish. For Beta fish I would keep well clear as well as some other fish as well. The output can be set in 10% steps.
I use the mesh guards which came with the gyres which are two years old and still good. Probably does affect their output but plenty of head room
To be fair I use an AI Nero 3 power head currently for additional flow on my current 100 litre - it’s a great bit of kit, I have it on a slow pulse mode to vary the intensity of the flow for a more natural ebb and flow effect.
That said though, even though the Nero 3 has a nice wide spray pattern the water velocity is still a lot more than I’d like it to be to get leaf movement at the opposite end of the flow direction.
The flow in the majority of reef tanks that I have seen is far more than we’d have in a planted tank, and miles more than I was shooting for when I was trying to come up with the design in this thread.
To be honest I’m quite possibly asking for the moon on a stick achieving even distribution with very low water velocity on a high tech tank.
The real world answer is probably to remove the requirement, or at least lower the importance, of good distribution, which kind of leads you down the path of low energy/low light. To be fair, that’s the way my preferences are starting to lean anyway, as I fancy a more habitat style layout for this tank when it eventually gets set up.
Andy Pierce
Member
I tried CO2 gas injected into the air pump airstream so the CO2 was only in the main bubble stream and not through any type of atomiser/diffuser in my closed top tank and that seemed to work just fine to get CO2 into the water column as measured by a drop checker: CO2 diffuser, Fireplace aquarium. The hood doesn't need to be totally air tight, just sufficiently closed to not let air currents rapidly sweep away the CO2 enriched air layered on top of the water. I wouldn't recommend a layer of pure CO2 on top of the water but a CO2-enriched air-CO2 mixture seems to get the job done. Others have noticed similar with open topped tanks in rooms that have enriched CO2 concentrations in the entire room (because the room has poor ventilation and is occupied by breathing people) e.g.: Concentrations of CO2 in the home - Reef Central Online Community
