Controlling CO2 levels efficiency

[Zeus.]

Hi all

I'm new not even got my tank yet (but we will skip that bit) been reading a lot.

So

We are after the CO2 level getting to the ideal level fast then staying there without becoming toxic to the inhabitants off the tank but high enough for optimum plant growth, but we end up with a bell curve OFC

so we are after a Table top not a bell curve ideally

( sorry just a quick job)

So ignore the cost for a moment. and just have two soleniods, needle valves, diffusers etc and just have one soleniod switch off once the "Just right" CO2 level is reach.

ovbiously you would need to play with the BBS until you hit the sweat spot

posted elsewhere thought a bit, slept on it and-

If folks are not doing it why not.

heres my take on it.

the CO2 gets into the water at a constant rate the diffusser as far as I'm aware its on or off, yes their is the pH controller method but that has issues with its use. but the C02 injection method is on or off we don't have a throttle on it the controller just switches it on and off.

My analogy

Our CO2 level is a plane on the ground,with limited fuel. we have mountain to over (we wont the CO2 at optimal level fast for obvious reasons) the engines can be on or off no throttle control. We have two engines. we can set the engine thrust (BBS) on the ground. we need 50% thrust (4 BBS) on one engine to cruise at 10,oo0 feet ( 25-30 ppm CO2) to to take off and clear the mountain we need both engines on at 50% (8 BBS combined). So we take off both engines ON reach cruising altitude switch ONE OFF. get close to our destination. switch other engine off. (or plane runs out of fuel in analogy). this would give us the ability to fly making a TABLE TOP flight giving max range (Fine control)

your thoughts and feedback welcome

Zeus

 

[ian_m]

We don't end up with a bell curve but a table top curve. You are forgetting that CO2 is always lost via surface agitation and loss rate is proportional to amount of agitation and CO2 level in the water.

So you start injecting CO2 and level rises but so does the amount lost at the surface. Eventually the loss rate matches the injection rate and CO2 stays level for the whole lighting period.

All done using one timer and one single solenoid and patience in setting it up.

 

[foxfish]

Looks like you are having fun working all your theories out
Thing is, for me at least, I switch my gas on two hours prior to lights and that gives me a one point Ph drop, the PH then remains stable for the next five hours and then slowly returns to where it was.
I feel this slow build up is not to shocking for my tank inmates but equally it is simple and effective.
I am all up for experimenting though, as long as it does not harm my fish.

 

[Zeus.]

You are forgetting that CO2 is always lost via surface agitation and loss rate is proportional to amount of agitation and CO2 level in the water.

So you start injecting CO2 and level rises but so does the amount lost at the surface

not forgetting the idea is just just at its Alpha stage didnt wont to start with a thread too long, some just read a bit then move on.

It works so why change it. Triumph did that with there 750 Bonneville for years, great for spares. But....

but im jumping in at the very deep end with a 500l tank ( wont go there also )

So looking at an inline duffusser its rated up to 500l so the the duffusser its going to be at its limit trying to get the CO2 levels to an optimal level, as will be losing CO2 as soon as it get in tank - equilibrium with the external enviroment etc etc.So it will take longer.

So using two soleniods etc will get there faster hit optimium level for CO2 then switch one off. then one maintains the optimum level.

I feel this slow build up is not to shocking for my tank inmates but equally it is simple and effective.

Yes good point but its the CO2 levels that drive respiration ( a take it as read for fish its the same as humans since we evolved from fish millions of years ago) the water isnt o2 deficient. the fish gupp not for O2 but to get rid off CO2 respiratory alkalosis
( although the pH change might effect the max percentage O2 saturation just like temp does, but irreverent its the CO2 levels thats gets the fish) same as in appollo 13 it was the rising CO2 levels that treated the astronauts not the lack of O2, have they made a CO2 scrubber in space.
its not like jumping in a cold pool of water, just get in it twice as fast thats all.

 

[doylecolmdoyle]

Personally i have been running 24/7 co2 on my tanks with great results, very little algae and great growth... everything seems very stable.

Both my high-tech tanks are small 12/14g so a slow rate of 1 bubble very 2 seconds 24/7 keeps my co2 ppm at about 25 - 30 at all times and when i compare to running my co2 systems on timers I am using about the same amount of co2 as I needed a much higher bubble rate when running on a timer.

 

[Zeus.]

Personally i have been running 24/7 co2 on my tanks with great results, very little algae and great growth... everything seems very stable.

Both my high-tech tanks are small 12/14g so a slow rate of 1 bubble very 2 seconds 24/7 keeps my co2 ppm at about 25 - 30 at all times and when i compare to running my co2 systems on timers I am using about the same amount of co2 as I needed a much higher bubble rate when running on a timer.

Yes ( me the noob is going to say), sounds like your uptake by the water is slow hence to maintain CO2 levels, so your just running it 24/7 so you dont have that initail 'mountain' to climb. ( whats the CO2 level before lights come on?).
------

What I'm thinking is how to overcome that initial mountain climb first thing. If one diffusers takes two hour to reach optimal level two with same input (BBS) would do it in less than half the time in theory due to less time for loss to the atmosphere. So less waste. more efficient

 

[ian_m]

So looking at an inline duffusser its rated up to 500l so the the duffusser its going to be at its limit trying to get the CO2 levels to an optimal level, as will be losing CO2 as soon as it get in tank - equilibrium with the external enviroment etc etc.So it will take longer.

For bigger tanks you will not be able to get decent CO2 distribution flow optimal levels using just one filter/spray bar/diffuser regardless of the CO2 levels you inject. Most people on bigger tanks end up having to use two spray bars, two filters and two diffusers in order to get optimal CO2. See picture below.

You could of course try using CO2 venturi injection, which has been done on very large planted tanks. But is a custom piece of gear and needs very large flow rates for it to work. There is something to consider that's not been done on smaller bigger (500l) tanks.

Yes good point but its the CO2 levels that drive respiration

Not convinced this is true for fish, as some people manage monsterous CO2 levels, even as high as 50-80ppm but have O2 injection and fish are fine.

Here is my attempt at significantly higher than 30ppm. Whoops. Fish totally unaffected.

 

[Zeus.]

input above

thanks for the input it all helps

Planning (got some, still to finalise everything) on having Two fluval FX6 ( output 2000l/h with media, got one working on bog wood in bin, with carbon), one with Inline diffuser in INTAKE ( have read up on it ) and also and independent loop on Eheim 3000+ for two external 300Watt heaters.

Thinking of having the 'Thrust' inline diffuser on this independent loop, should get the CO2 levels to optimal levels pretty quick IMO

 

[ian_m]

How have you coped with the 25mm pipe size of FX6 and 16mm of typical diffusers.

 

[Zeus.]

took it to the Barr team

 

[Zeus.]

How have you coped with the 25mm pipe size of FX6 and 16mm of typical diffusers.

havn't yet in practice, but have checked out the flow rates for the diameters off the pipes and paln the split the STD 25mm int daimeter pipe with 'Y' fitting to 16mm pipe then back to 25mm again. Well the maths work out flow resistance should be minimal

 

[ian_m]

havn't yet in practice, but have checked out the flow rates for the diameters off the pipes and paln the split the STD 25mm int daimeter pipe with 'Y' fitting to 16mm pipe then back to 25mm again. Well the maths work out flow resistance should be minimal

Yes that's the way to do it. Might want to put a valve in the non CO2 route so you can force the flow through the diffuser side if required. Also remember to stainless jubilee clip all joints.

Actually what some people do is leave straight route bypassing the diffuser 25mm with valve and have the CO2 route 16mm as gives more control of flow rate through the diffuser.

 

[Zeus.]

Yes that's the way to do it. Might want to put a valve in the non CO2 route so you can force the flow through the diffuser side if required. Also remember to stainless jubilee clip all joints.

Actually what some people do is leave straight route bypassing the diffuser 25mm with valve and have the CO2 route 16mm as gives more control of flow rate through the diffuser.

Opps My bad plan on Inline Atomizer CO2 Diffuser best get editting

so flow would be even longer time in pipe slightly better

 

[Zeus.]

The idea is to basically have one of the filters as a Cerges reactor in a way - slow the bubbles down, ups and downs of flow, lots of media to bump into more time to get into water less bubbles in tank. As for there mass of bubbles from the indepentent loop in the morning thrust stage, well be like Xmas

 

[ian_m]

Before you connect your diffuser inlet you might want to consider what CO2 can do to rubber seals in the filter.

http://www.ukaps.org/forum/threads/bubble-counter-seal.43147/

havn't yet in practice, but have checked out the flow rates for the diameters off the pipes and paln the split the STD 25mm int daimeter pipe with 'Y' fitting to 16mm pipe then back to 25mm again. Well the maths work out flow resistance should be minimal

Not quite.

16mm tubing is 200mm2 and 25mm is near 500mm2, which explains why people put the diffuser on 16mm bypass of 25mm straight through tube (with valve).

See post below on how to hook up 16mm diffuser to 25mm pipe.
http://www.ukaps.org/forum/threads/fluval-fx6-with-16-22m-hose.42310/#post-455324

 

[Zeus.]

CO2 can do to rubber seals in the filter - found thread somwhere else bit back folk using it for few years np if it does move CO2 input to outlet of filter and replace seal/impeller.

Pipe size, sorry my mistake wasn't clear on plans,plan going to spit Y the pipe to two 16mm pipes.diffuser on one side, bypass on other. (Used the Bernoulli equation did the maths-np )- then back to 25mm

 

[Zeus.]

Well I think I may have come up with an original Idea/modification/ technique
So

Legal disclaimer- Zeus and UKAPS or any other website takes no responsibility or liability, that if you or any third party you tell about this technique. Using CO2 can be dangerous to your livestock and humans leading to respiratory alkalosis and/or death. Any use of this technique is done at your own risk. However feel free to try use the technique at your own risk. I/ we welcome any feed back.

Zeus

May be premature But If any one else can make a valid claim to the idea/modification/ technique pls let me know before I name it.

 

[doylecolmdoyle]

Yes ( me the noob is going to say), sounds like your uptake by the water is slow hence to maintain CO2 levels, so your just running it 24/7 so you dont have that initail 'mountain' to climb. ( whats the CO2 level before lights come on?).
------

What I'm thinking is how to overcome that initial mountain climb first thing. If one diffusers takes two hour to reach optimal level two with same input (BBS) would do it in less than half the time in theory due to less time for loss to the atmosphere. So less waste. more efficient

I am not sure what you mean by the "sounds like your uptake by the water is slow" the only time that more co2 needs to be dissolved into the water if I am running 24/7 co2 is after a water change otherwise my level of co2 is 25-30ppm 24/7. Lights come on and my plants are pearling 15 minutes later. I also run a surface skimmer which helps control co2 and create a nice amount of surface agitation.

 

[Zeus.]

I am not sure what you mean by the "sounds like your uptake by the water is slow" the only time that more co2 needs to be dissolved into the water if I am running 24/7 co2 is after a water change otherwise my level of co2 is 25-30ppm 24/7. Lights come on and my plants are pearling 15 minutes later. I also run a surface skimmer which helps control co2 and create a nice amount of surface agitation.

Firstly I have zero experience, What I said is just theory. What you works for you thats great so pls do not change anything on what I say. I said slow as if your night period is longer than day period you should be using less CO2 but said said about the same, which sound like less CO2 was diffusing into water as it was saturated at near to the diffusser therefore more bubble escaping to surface - hence slow - at lower BBS there is a higher duffusion gradient so fast uptake all any CO2. But at a higher BBS once the initail CO2 (2 BBS) is taken up the extra CO2 (2 BBS) has to fight against a higher diffusion gradient. as the waters affinity for CO2 is limited. Hope that makes sense

Personally i have been running 24/7 co2 on my tanks with great results, very little algae and great growth... everything seems very stable.

Both my high-tech tanks are small 12/14g so a slow rate of 1 bubble very 2 seconds 24/7 keeps my co2 ppm at about 25 - 30 at all times and when i compare to running my co2 systems on timers I am using about the same amount of co2 as I needed a much higher bubble rate when running on a timer.

My take/theroy would be.

Lights on say 8Hrs so for 14hrs of night your CO2 input plus plants CO2 would yeild a higher CO2 ppm but not dangerous as everything is fine. But there could be times that the CO2 level is getting close to critical for fish. Lights come on and plants very happy as plenty of CO2 and the CO2 ppm of tank must drop as the plants are using it.

You said to get the same level of CO2 with it on in day only you had to run it at a higher level (BBS) to get it to your chosen level. Which should use less CO2 if you was hitting the same CO2 ppm on both methods. But with the 24/7 method you run a higher chance of respiratory alkalosis for you fish.

surface skimmer = increased water agitation = greater CO2 loss - Pls dont turn it off if your 24/7 with CO2 as a clean clear surface helps CO2 escape from water too.

What I am proposing is if we was to take your tank for example (pls don't do this on my account your risk OFC)

one diffusser/reactor (what ever your using) you know the rate the maintain isdeal CO2 levels for tank 1-2BBS that would come on say 30mins before light period. at the same time a second diffusser/reactor would come on at the same time say 3BBS you would reach you ideal CO2 ppm faster then the second one switches off. fish happy at night plants happy in day uses Less CO2, but more initail outlay on hardware

 

[Staticrzr]

man, is it just me because I'm not British? I can't understand a word Zeus says. I read some of his posts two times and still nothing is making any sence.