Discussion in 'Carbon Dioxide (CO2)' started by chris1004, 4 Dec 2009.

  1. chris1004

    chris1004 Member


    Wasn't sure where to put this post but seeing as only the 'c' is missing and its a gas guess here is as good a place as any.

    What I would like to do is initiate an informative discussion about the importance of oxygen to plants and in particular there health. Now I'm no planted tank expert but if the right levels of co2 are vital then surely so must the o2 levels be of equal significance in the no light cycle. With this in mind I added a large air pump on a timer set to come on when lights are off and the plants seem to have responded well. But I can't be certain that this is the cause as I changed the dosing levels at the same time,(I can hear Clive laughing as I wright :) ).

    I always have a constant surface ripple but try not to gas off the co2 to quickly with it, I also have quite a high fish load which is why I'm now looking at o2 or more specifically lack of o2 being a contributory factor of poor plant health and therefore algal outbreaks, not that its a massive issue in my tank.

    As I said I'm certainly no expert and the above is kind of meant as an opener for an informal discussion on o2 please.

    Regards, Chris.
  2. andyh

    andyh Member

    Hi Chris

    I also thought about O2 in the aquarium, but in the ended concluding that it also added problems. Especially using a air pump and air stone. I found that it helped all the CO2 escape very easily to that point that it caused algae in my tank (because of the fluctuating co2 levels.) The plants if in an ideal environment will produce O2 (pearling).

    have a read of this thread, its the one were i realized that the introduction of O2 overnight was causing me problems in the form of Staghorn Algae due to the CO2 levels going up and down so much.

    and yes i suspect Clive will have something "matrix" related to say about this, he certainly helped me to get to the bottom of my little challenge! :thumbup:
  3. samc

    samc Member

    some people who use lily pipes raise them at night to add o2 when the plants dont produce it. this is to not only help the fish but for the bacteria which is all over. the bacteria does help stop algae which is why mature setups get less
  4. plantbrain

    plantbrain Expert

    Lily pipes suck.
    They break like, well, glass.
    They have very limited adjustments.
    They cost $$$
    They have few options for current direct and spread.

    A surface skimmer is a much better option, Loc line, powerheads, air stones etc on timers etc.
    These can be configured to do many different currents, and thereby O2 exchange rates(as well as changing the rates of degassing for CO2).

    Balancing good O2 and then adding CO2 enrichment is the best way to go about it.
    If you want high pearling for a photo shoot, open house etc use higher gentle current flows like from low pressure wavemakers, then turn them off for 1-2 hours and watch the tank pearl like mad. This added current allows you much more CO2 enrichment to be added since the higher CO2 is also off set by higher O2 and fish are less stressed then, and have higher O2 for the other 60% of the 24 hour day cycle when the lights are off.

    The effects are better and cleaner plants, better filtration, cleaner tank, better/faster break down of waste etc, and better eating by fish, less stress to fish.

    All very good things.

    If you can only barely add enough CO2 via a DIY or an under powered reactor, diffuser etc, then this might not be a good solution. But with a CO2 system that is set up well, it should never be an issue.

    Good rule of green thumb: enough current so that surface moves but does not break the surface.
    O2 drives many things, most importantly is the fish health. We can adjust CO2 based on that requirement, not add fish to suit low O2 and high CO2.

    I have had several lily pipe sets, I doubt I'll ever use them again.
    I still have a set on my ADA 60p, but am going to try and get a replacement made.
    Impossible to adjust, clean, point current where I want etc.

    Tom Barr
  5. Nick16

    Nick16 Member

    Surrey, UK
    so is there a piece of wonder kit you can suggest? perhaps a good surface skimmer?
    i have always stuck to good old spraybars and it works well, seeing as you can adjust them, you can have half of it pointing at the surface and half into the mid range of the tank.
    This coupled with a koralia or two is fine.
  6. chris1004

    chris1004 Member



    Andyh I think reading between the lines that a lot of your problrms were because your tank was only 6 weeks old and therefore not mature. You don't say wether your filter/s were established or not but my betting is that ammonia was more likely to be your problem than the air pump, that and not getting the co2 high enough for when the lights come on.

    I haven't (fingers crossed) thus far suffered with algae due to having an air pump on all night, its a very large air pump aswell (400lph) with an air curtain diffuser stretching right accross the back of the tank. Its on a timer and comes on when the lights go off and off 5 hours before lights on. First thing in the morning the DC is blue but by the time the lights come on its lime green/almost yellow. I've set it up as much for an experiment as anything else, the DC proving that the co2 is being degassed at night. Clive pointed out that this is not efficient use of co2 on that thread you linked to, which I've read right through, and I totally agree with that (quote" its like having the windows open with the heating on"). But I think that possibly having an excess of o2 available when the plants need it (i.e. at night) would contribute to there well being. My fish certainly seem a lot more lively in the morning than they did, which for that reason alone its worth sticking with for the time being at least.

    One thing I don't quite understand though is that it is well known that fluctuating levels of co2 cause many types of algae to bloom, but my DC is going from blue to lime green to blue again over a 24hour period which indicates that the co2 is fluctuating widely. Yet I have only a tiny ammount of algae which you have to look extremly closely for. This is after about 6 weeks of installing the air curtain. In fact I have even less algae now than I did before, so the situation has definatly improved. But as I said before I had tweeked the fert mix a little so it may have been that is why its improved and may have nothing at all to do with the air pump. No way of telling for sure but the air pump has definatly not worsened the situation. All the plants are really strong, healthy with great colour and pearl like they never have before in the evening at the ebd of the photoperiod.

    My train of thought is leading me along the lines that if we take so much care to give our plants non limiting conditions through the photoperiod (i.e. co2, ferts, light) then why not extend this to the other 60-70% of there life cycle and supply non limiting o2 aswell when lights are off.

    Leading on from that could the reason why so many people struggle whilst seemingly having everything right (i.e. co2, ferts, lighting) be because they suffocate the plants when the lights are off?

    Do plants that utilise extremly high levels of co2, ferts and light also require high levels of o2 to keep things in balance?

    Regards, Chris.
  7. chris1004

    chris1004 Member

    Come on guys I was hoping for a bit more of an in depth discussion on this, where's Clive when you need him?
  8. andyh

    andyh Member

    You could be right about that but then again, The filter was very mature and followed the 10x rule in fact its probably 12x rule. Ammonia was not a problem.
    My CO2 came on 3 hrs b4 the lights and was at a good bubble rate (not quite enough but still a good rate.)

    The air pump came on at midnight and stayed on till 13.00 the next day my co2 kicks in mid afternoon and off we go. The problem was that by the time my co2 came back on my drop checker was pure blue. The only think i can liken this to was a yo-yo effect.

    The minute i stopped the air pump/surface agitation i was managing to keep my drop checker green for most of the time.(less peaks and troughs) I create surface disturbance using a powerhead now.

    All i can say is i followed Clives advice and it worked for me. One thing i learnt was that flow and distribution of CO2 (the amount of CO2 put into my tank still suprises me now but my drop checker and plants are all good) and ferts in the tank was one of the most important things. Once i got this right the staghorn was gone. One thing that helps me is that my tank pearls like a demon and the amount of o2 being produced by the plants is amazing.

    Keeping fish healthy is my priority (as i am fishkeeper trying to be a planted tank enthusiast). You can tell quite easily when you get the co2 levels wrong as your fish will tell you! (they will be at the surface gasping!)
    Its good to experiment and i tried the same thing as you. I put a nice powerful airpump with two air stones on and took my influence from amano. It just didnt work for me. Again every tank is different and dependent on your plant mass, dosing, lights, co2 and water changes will also effect the outcome.
  9. aaronnorth

    aaronnorth Member

    worksop, nottinghamshire

    between 25-28C the average O2 saturation is 8.4-7.9ppm respectively.

    Considering we have lots of plants I think we can be fairly confident we are always close to that point.

    5ppm< x >15ppm

    You need a value of x, otherwise, to the left plants/ fish die. To the right, fish die (not sure about O2 toxicity in plants).

    So the fish are a good indicator to our O2 levels, and if they are surviving happily, then the chances are so are the plants.

    Also, you said the plants have responded well, in what way? can you exaplain please.
    And can you also list what you changed about the dosing regime? For example if you added more Phosphorous then this will increase photosynthesis rate.
    Even still, it could just be a placebo affect.
    Thanks, Aaron
  10. chris1004

    chris1004 Member

    Hi Aaron,

    Ok I've changed quite a few things over the last couple of months. Lets start with the hardware.

    I increased the total flow rate about 3 months ago from about 17x tank volume on 24hours to 25x tank volume during the photoperiod and 10x tank volume when lights are off. Also flow distribution was altered at the same time as adding the second Koralia. As previously mentioned I added the air curtain 2 moinths or so ago at the back aswell which would add to the 10x flow rate when the the lights are off but the flow dynamics are completly different.

    As if thats not enough there have been a lot of changes to the ferts aswell.

    Around 10 weeks or so ago I changed my Trace element mix entirely from the AE version to the Haak micro+FE following discussions with James.

    On top of this for the last 2 months I have increased the KN03 from 1.5 teaspoons a week to 2 and the KH2PO4 from 1 to 1.5 teaspoons a week (250 Litre tank). The Mgs04 was reduced from 4 to 1 teaspoon a week but the ammount of equilibrium that I have been using was increased considerably from 1 to 3 teaspoons per 100litres which should now supply enough magnesium and calcium for the plants at a ratio of around 4:1 calcium to magnesium. This was after I realised I may well have had a calcium defficincy because the ammount of MGS04 that I was adding with my macro mix was skewing my GH readings which I strive to keep around 6-8dgh to suit my fish.

    Whilst talking about the fish its worth pointing out that I also removed a couple of the larger specimens which obviosly reduces the ammonia load that the tank was under.

    Before changing and specifically before adding the air pump the DC would still be green in the morning but lime green by the time the lights go on now though its blue in the morning but still lime green when the lights go on and almost yellow when they go off in the evening.

    Firstly the difference in the fish is good, their colours are more vibrant and they seem a lot more active their diet hasn't changed but they do seem to eat with more gusto.

    As for the plants I can only describe them as 'showroom condition'. Clean, vibrant and healthy the red colours in particular have increased dramatically (probably due to the trace mix). Although I had the beating of the algae a while back the plants never looked as good as they do at the moment nor was the growth rate as dramatic. There is no algae either except for a bit growing beneath the gravel against the glass which I clean off periodically and the overall cleanliness of the tank is pristine. Sorry but I just don't know how else to describe it, time for a photoshoot me thinks.

    So you see there have been so many changes thats its impossible to say its because of x, y or indeed z for sure and I know full well that Clive told me this would happen if I continued using a scattergun approach and I also realise its probably a combination of the above that has worked for me. I love the way things are going and looking, its now time to start reverse engineering if you like, not that I can't live with it how it is but I'm always looking to learn more.

    Which has led to this thread and my questions about O2 and its significane to plants in particular and my thirst for related knowledge.

    Regards, Chris.
  11. chris1004

    chris1004 Member

    I'm thinking that this is what's happened in my tank as a direct result of the air pump being on at night.

    Thats happening in my tank aswell at the moment but its not causing algae to flourish. It is probably wasting co2 and it doesn't appear to be advesley affecting the fish like some will have you believe. i.e. the common advise that fluctuating levels of ph is bad for fish health.

    He's usually right and has helped me out loads so can't argue with that, where is he I have missed his brand of humor on here lately?

    Dito that mate but the more success I'm having the more I'm getting fascinated by the plants. To be honest I've been keeping fish so long now that its almost second nature and I find them infinatly easier to look after than the plants.

    "influence from amano". Please expand, I'm not familier with his work but have obviously heard the name many times.

    Couldn't agree more.

    Hark at me multiple quoting I've just found out how to do it, boy do I feel clever this morning next thing you'll know I'll be setting up the video recorder without my gransons help. :thumbup: :)

    Regards, Chris.

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