How much do you think you get from microbiological activity?
They will, this is the situation you deal with when you work with the re-mediation of organically polluted water (commercial aquaculture, sewage treatment etc), here you have huge BOD, and concurrently a large production of CO2. Work on Eichornia has shown that the addition of floating macrophytes can turn a lagoon from a net CO2 producer to a net CO2 sink. (<"Floating Aquatic Macrophytes Can Substantially Offset Open Water CO2 Emissions .....".>)So if we encourage high oxygen levels in our non co2 tanks via surface agitation it would make sense that bacterial breakdown of rich soil sediments would be maximised. Some of the Co2 produced in this manner would/could still be utilised by plants before it has a chance to reach atmosphere? Or would we reach a point where co2 is off gassing faster than it is being produced. Surely the plants would still get some of the co2 produced via bacterial activity?
Scientists make a distinction between the CO2/HCO3- which are "Dissolved Inorganic Carbon" and other carbon compounds "Dissolved (or Total) Organic Carbon" (DOC or TOC).Are we talking about CO2 in gas form or all kind of carbon based compounds that can be consumed by plants?
Hi Edwin you must mean its a hypothesis. In science, theory means an established idea usually having good quality evidence and usually part of an overall consensus.Sorry about two questions at the time. Of course I have no scientific proof it's just a theory. As is a theory that organic soil provides lots of CO2 available to plants. It provides carbon in organic and non organic compounds that plants find much easier to consume in low dissolved CO2 environment.
I like lean nutrients, and it could well have been low oxygen. The problem with JI No.3 is that you have a lot of potentially oxidisable material and a nitrogen source (again possibly as ammonia (NH3)).My plants died, algae took over and I lost a couple of fish along the way that where showing signs of rapid breathing. In fact, i remember losing a fish every couple of weeks in this manner and wonder whether it was all due to low oxygen. I chose John innes no3 but have read that this soil is not the best of choices. What's more, it was unmineralised.
Very soft water could also be a problem as well, even with some water changes you could run out of HCO3- and nitrification would then lead to bio-acidification or "old tank syndrome". This used to be common when I started keeping fish and "aged water" was considered beneficial. I never changed any of the tank water, and used to go through cycles of fish death on a fairly regular basis every 6 months or so.termed as very soft by the water board
I don't think the chemical composition of the water is that important, people have successful low tech tanks in very hard water ("Akwascape" or "Troi"), soft water ("BigTom" etc) you just need regular water changes and an indication of when plant nutrients are lacking. I've suggested the <"Duckweed Index">, as an indicator of when plants need feeding, mainly because the "Duckweed" isn't CO2 limited.Sometimes I often wonder whether some of the success stories relating to no co2 tanks are almost 'accidental' in the sense that these people just have really good tap water.
They are getting some additional CO2, which will be beneficial to plant growth, but not the level of CO2 that is required to change the pH of the 4dKH solution (indicated by the change of colour in the "bromothymol blue" pH indicator solution).With the extra surface ripple my ph is not falling yet a can visually see an abundance of tiny co2 bubbles all over the tank. My drop checker also remains blue. Does this mean the plants are not getting the dissolved co2?
Yes, size of the bubble, and dwell time, are the important parameter for gas exchange with direct aeration. I think that your idea would work pretty well.When I kept marine aquariums I started out using air-driven “Sander” counter flow skimmers driven by the excellent Rena 301 air pumps. These were far more efficient than many gave them credit for if set up properly and kept in tune, key being maximum “dwell” of the fine air bubbles (limewood airstone) within the contact tube rather than rapid throughput. I used to extend the tubes to the max possible to increase the dwell time.
Yes it isn't conclusive, because it is just a snap-shot and because we can't measure the level of dissolved gases directly and have to use pH as a proxy of the CO2/O2 ratio.Simple experiment, messy to interpret, but something interesting is going on
There are just a lot of unknowns. Some of the oxygen used by plants for respiration is from oxygen "stored" in cells and lacunae during photosynthesis.Or does higher plant growth during the day generate more oxygen, leading to stronger metabolism during the night and thus more CO2.
Interesting read! Couple of questions, firstly, all taken into account here, when would be the best time to perform a water change, before lights come on or after? Just thinking if we have a small amount of co2 built up over night would it be best to let the lighting period have what's there and perform the change after lights out would be more beneficial and the extra oxygen caused by it be better through the night?
Secondly, when it comes to floating plants, keeping a fair amount of them is obviously a good thing for stripping out waste but would having too many floaters reduce the amount of gas exchange interface on the surface?
Just remembered there was a third question If we are saying increased o2 then leads to more co2 through increased de-nitrification is there a place in a non co2 setup for those twinstar and similar products which appear to release hydrogen to break algae cell walls which then converts to o2 increasing o2 levels>co2 levels? Maybe that would be behind the claim that they are beneficial in planted aquariums.
I love HMF, i run mine on cheap smal filters, either two small ones or a larger one. I use the outflow"pipe" just below the surface angled slightly upward to get some surface movement or just above to break the surface.thinking of using an HMF
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