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CO2 is one of those critical things that aquatic plants folks should really focus on.
I've nagged folks about this for a very long time, and I will likely nag you to the grave.
Complacent experts, newbies, test kit freaks, all of you(and myself included).
Poor CO2 reduces growth and is responsible for nearly 95% of all algae related issues.

Now KH test kit variance is one issue, making a reference standard to compare you KH test to is a very WISE idea to check the accuracy. I've seen many folks have very high CO2 predicted levels, yet fish were fine, but another than has barely 30ppm and the fish are gasping. It cannot be that both are at the same CO2ppm level becaused we would expect to see the same behavior from the fish. Instead we see very wide ranges and impacts on the fish(as well as plants).

So it's much more likely that it is the testing method, rather than anything else.
pH is the best thing as far as accuracy for CO2 measurements using a pH probe and no electrical equipment runnign when the pH is measured(stray current will depress the pH giving false high ppm CO2 levels).

KH test kits have consistency issues (see recent post) and in some places, although rare, non bicarbonate alkalinity exists(recent poster in NM has significant borate alkalinity, desert regions generally).

Addressing this issue by making a reference sample will take care of the KH issue.

The next issue is more interesting for many of of you.
I'd suggested that the venturi DIY reactor I have shown folks on my site is better than any reactor. Well, initially, and perhaps partially true, is the purpging effect of gas build up.
This gas is some O2 and some CO2, but very little "air".

As the gas is expelled, consistently I see better growth, this is not due to O2.
So why would a mist of tiny CO2 bubbles vs dissolved CO2 in solution do better for growing plants?

I addressed the O2 issue simply, I used a diffuser disk for CO2(no O2 gas build up occurs).
But that did not do it __alone__.

I wondered why.

So I placed the diffuser disc near similar current like that produced by the venturi reactor after is starts mistuing the gas out the bottom.

Lo and behold, Bam! Excellent similar growth.
Not the kind of so so growth, but pearling like nothing you have ever seen or perhaps only in a very few well run tanks right after a water change. But I'd not done a water change for a week.
I tried it several times on 4 tanks, same result in each tank. Day after day, intense pearling even with fair good current.

So why would this mist be better than dissolved CO2?

For one thing, it's __pure CO2 gas__, which flows much faster than dissolved CO2 liquid.
The flux rate is much faster with pure CO2 gas than CO2 dissolved in water, so the plants get more CO2 and a more concentrated form.

Some folks may not like the bubbles, some might not like pearling.
But I sure do.

I can say that the venturi effect is one of CO2 now, and not of O2 by using the diffuser disc to rule out O2.

So that just left CO2 and the gas vs dissolved form to consider why one method was better in terms of plant than another.

Both flow and actually having some gas in the tank itself seems to be the key here.
So those disc are not so bad and neither are the venturi reactors.

You can make a purge loop for external reactors by making a hole 1/2 down and running the air line back to the intake for the power head, caniter filter etc, this will not add bubbles but will reduce the gas build up inside the reactor.

The real issue is having gas bubbles in the tank and putting them where the plants are in that form.

I think folks should really consider this/these idea/s and try them.
I've had very intense pearling and have over the entire routine time frame, not just for a day or a few days.

Be careful and watch the fish, CO2 levels when doing this, I've not had any fish issues yet. Make sure there is some surface movement. If you use disc, clean them often(monthly).

For larger tanks, they make 6x1" diffuser stones for about 60$ than can be used set along the bottom back gravel layer so they will not be seen. wwww.aquaticeco.com sells them if interested.

In any event, this notion of having tiny gas bubbles floating around very dissolved CO2 might solve many folk's problems and improve those who seek better growth.

Nitrogen is an essential element, but only 1.5%, vs 40+ % for Carbon, it is very very wise to focus on this if you seek better growth.

With good CO2 levels, even the wimpy plants do very well(Tonia, ES, Eirocauleon) algae dies, pearling as intense as you have ever seen it day after day will occur.

I think the gas bubbles might also be less of an issue for fish since it's not dissolved into solution also.

The nutrients can be addressed easily by doing EI, so you know there's enough, so all that's left to really focus on is the CO2.

So I have been playing around trying to figuire out a good way to reproduce max CO2 without causing issues for fish, and adding enough for the plants.

The CO2 mist + current seems to be the best method.

This can be done with a reactor or a diffuser stone/disc.

Also, folks using spray bars, turn them vertically, next to the intake and place the disc down near this also. This hides the bar, the disc, intake all in one place. Having the spray bar current blowing along the back side the tank wall seems to give good flow characteristics+ near the disc, the water blows out and away from the intake and circles around to the intake.
Since water is being blown directly away from the intake, this gives optimum mixing.
Since water is being blown directly on top of the difusser, all the bubble mist is being blown all over the tank.

The results are easy to see.

The other issue is not to trust the test kits so much until you see the type of pearling like this, no BBA growth etc, slowly and patiently add more CO2 till you get the pearling and good growth. Basically use the test to get close, then tweak(add more) carefully and slowly.
Do not go overboard, do it slowly and observe the plants/fish. Your test may give you high numbers, but if the fish are fine, then it's okay.
Turing off CO2 at night will help add the margin of safety also. We add CO2 for the plants, not to maintain pH. Some leave it 24/7, but mainly out of convenience rather than methodology. With disc, running them at night can cause issues, anyway, you can save 2-3x the gas by not running it at night. We know fish don't care about the pH change.

Regards,
Tom Barr

www.BarrReport.com

Hi Tom,

Nice post and info.

Strangely it echoes something I've seen by accident in the past couple of weeks. I'm now feeling much better.

I was running a co2 reactorwith a small pump, about 100lts per hours. This reactor has 2 chambers , the topis a kind of vortex effect which forces the co2 straight down into the bottom chamber which is filled with ceramic rings, the theory being in the chamber that the bubbles don't escapes quickly and are churned up by the rings and dissolve.
Anyway as I said I it a small pump on it. I was cleaning the reactor last week and i managed to drop the pump on the floor. Wrecked. I had a look around for some old powerheads I had lying around. Only one I could use was much more powerful 600 lts per hour. Stuck it on , switched back on the gas. The bigger water flow was pushing the gas through the reaction chamber with the ceramic rings much faster. Result a lot of tiny bubbles being blown out the reactor outflow (still a good bit of bubbles bouncing around in the reator too). These tiny bubbles would rise up the middle of the tank then the spray bar current would hit them and they were getting blown around the tank. Tiny bubbles everywhere.
My first thought was , well this won't do, the co2 won't be dissolving as efficiently, better get a new small pump tomorrow. Came home next evening looked in the tank and wow, plants seemed to be pearling like nuts bubbly leaves everywhere, pH was a bit lower then usual. As I'm looking I'm beginning to wonder is it really pearling or are the Co2 bubbles getting trapped under the leaves ? But then I noticed the bubbles on the plant were much bigger then the Co2 bubbles and plants away from the main flow of Co2 bubbles were also "pearling".
This had me way confused as the conventional wisdom was those little bubbles of Co2 would just rise to the top and burst, effectively a waste of CO2. This seemed to be contradicting what I was seeing.
I decided to leave the bigger pump on to see how it played out.It's only been running this way for a week (I also decided to change from 24/7 CO2 running to just inject during lighting period). Seems to be working a treat. Reineckii which was always a moderate grower has decided to go nuts, Hygro Augustifolia has side shoots popping out at every node, Ammania which used to need a trim every week has decided it now wants a cut twice a week (great that's all I need - more trimming ), lots more growing tips on mosses. My nitrate "test kit" - the Augustifolia showed a problem after a few days, a few of the bottom leaves yellowing , a sure sign of low No3, sure enough when I checked, No3 was low so I upped that and everything else to keep up with the extra growth.
It seems you've found an explanation for what's happening. I'm feeling much easier about it now.

I'm wondering now if I should try the diffuser/spray method you mention or stick with the overpowered reactor ? Be nice to be able to replace a powerhead and reactor with a small diffuser? More room for plants

With regard to the whole Co2 thing I'd just like to throw in my own $0.02 for what it's worth (it's National Mixed metaphor Day ). Some seem to think that going Co2 is the way to solve all their problems and can get caught out by it. Pressurized especially can lead to a bit of complacency. It can be tricky to get running properly - dodgy needle valves, crappy reactors etc. You need to keep an eye on it, make sure it keeps doing what it's supposed to. Needle vavles go wonky, controllers get out of whack. It's not just a switch on - walk away thing. Lots get caught out by the sudden increase in demand for nutrients, got to keep on top of that too. Even an increase from say say 15ppm of CO2 to 30ppm will drive nutrient uptake considerably and it needs to be adjusted upwards accordingly. A lot get caught out on this.

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

The issue is of delievery.

Do you desire to add CO2 fully dissolved into water at a lower concentration, or add very high contration and lose a little?

More rapidly CO2 delievery is certainly better.
A good mix of tiny bubbles and good flow achieves this.

Everyone likes pearling I've ever talked to, it makes everything look and appear better and does seem to reduce algae.

Never a bad idea to turn something on it's head and try it upside down:-)

The same was true for PO4 when we started adding it.
Seemed counter productive at the time.

Regards,
Tom Barr

www.BarrReport.com

Bensaf,

You could look into one of those diffusers. I have bought one of those a while ago to replace the chunky JBL diffuser that came with my CO2 set. I placed it at the bottom back of the tank and used a diversion nozzle to direct the current down and on the diffuser. The next thing I've noticed were tiny CO2 bubbles all over the tank, something that didn't bother me in the least. With time I also concluded that the plant growth is better, but I never really thought that it had anything to do with the tiny bubbles. In any case, I'm very happy with that diffuser not only because I see better plant growth but also because now my CO2 tank lasts much longer than it used to. When using the JBL diffuser I needed to refill my bottle(1/2kg) every four months or so and now It's been running for about four months and the gauge still shows a full bottle.

Although my test kits (KH and pH) show CO2 levels of around 35 - 40ppm, I will try and up it a slowly to see what effect it has on my plants.

Thanks for the post Tom, no wonder you're our plant guru.

Ah Dymax and Matrix ! You get them there. I know the guy who does the distribution for them in Jakarta. I can get them dirt cheap. USe their light fixtures and filters too. I won't depress you with the prices They work good.

I'll have a look when I see him next weekend, I might give it a shot at least do a comparison.

I haven't taken all of Tom's advise above yet. ATM my filter is on one side of the tank and the Co2 set up on the other. I'll have to move both to the same side which'll be a bit of a squeeze. At the moment I've put a small pump near the reactor outlet to really throw the bubbles around.I'll rig it up properly during the week.

What size is your tank again?

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

My tank is 100 litres only so I have the smaller diffuser. I think their really great but their only downside is that you have to clean them properly every once in a while. I do it now with my weekly maintenance -- take out the diffuser first, soak it in the sink in water with washing liquid and bleach and then when I'm finished with my maintenance I take it out, was it very well and put it back. That tank is all I could afford and could squeeze in at the time, living in a small house.

As I was already having CO2 bubbles around my tank I just had to turn the needle valve a little bit more to get my CO2 levels a bit higher. I've not really tested it to see what effect it has on CO2 levels but I do keep an eye on the fish and none of them seem to suffer.

The results so far...

Much more pearling indeed from the plants. There's a lot more CO2 bubbles in the tank as well but on some plants you can clearly see that it's from photosynthesis and not CO2 bubbles.

The downside, though, is that it looks like my plants have become really greedy and want more nutrients. One plant in particular -- Ludwigia inclinata var. verticillata "Cuba" is suffering. The leaves have snapped at the tips as if someone has broken them and it clearly needs more iron too. I was adding 5 - 10ml of Flourish every other day and have started adding about 5ml more now but don't see a much of an improvement yet so I might just pour the whole bottle in... Well, I was guessing that the broken leaves tips are a result of boron deficiency but am not sure, any idea here?

My fish are all fine.

Untitled,

Very similar experience here !

I added a small powerhead over to the reactor output to blow the bubbles around. Works a treat there are micro co2 bubbles (so small they are very hard to see) everywhere even swirling around at substrate level. Definate increase in pearling. Fish aren't bothered , in fect seem to enjoy the extra current evrywhere. Didn't know Rummies could surf

I too have had similar problems as you have had with your Ludwigia. Difference being I've had this on and off for a while.Small twisted and broken leaves. But definately a bit worse the past week. The strange thing is it seems to come and go with me. New growth will look like crap and then it'll just return to normal. It will only effect some stems from a bunch of the same plant, others in the bunch remain completely normal.I've seen it on a few differenr species, easy and fussy ones. Never been able to get a handle on it. I've increased dosages of everything, but still it comes and goes. I'm beginning to wonder if it's a toxicity thing rather then a deficiency I get it most on my Ammania Gracillis , never enough to stop or seriuosly damage the plant , which always bounces back. But the one thing I've noticed is that the leaves effected will be the deepest darkest red That's why I began wondering toxicity.

I've noticed sometimes it can be accompanied by little black thin streaks on the leaf edge. Sound familiar ?

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Bensaf,

I had this happening in the past as well, but never to that extent. Perhaps a few leaves but never enough to have bothered me until now. I don't know what causes it, of course, but here are some of my thoughts anyway.

Firstly, some stems of Limnophila aromatica also show the same signs, although to a lesser extent. The Eusteralis stellat (and other plants) are fine.

As for a deficiency, it does make some sense to me as we increased CO2 and therefore increased nutrient uptake of the plants, so if we had a tiny problem in the past, it's bound to get worse with more CO2.

On the other hand, the recommended dosage for Flourish is 5ml for 250 litres. I add around 10ml at a time, which is 5 times more than my tank capacity. I also add Flourish Trace, which covers some nutrients not found in the regular Flourish. I also added a ball of JBL 7 balls to that plant which provides some more nutrients to the roots, but haven't seen any improvement.

As for toxicity, I used to do my water changes with 100% R/O water which rules out anything that comes from the tap. Then again, for my last water change I used 100% tap water thinking there might be something in the tap water lacking from fertilisers. Didn't really help.

There's also the iron deficiency problem which the plants (and the Ludwigia especially) are showing, while I think I should have enough iron in the tank. Perhaps it is something that prevents the plants from taking up nutrients properly?

The first time I've seen this happening was about 2 - 3 months ago and I'm trying to go back and think what happened then but I can't really point my finger on anything in particular. I've changed to flourish from TMG after I've first seen that. I've changed my diffuser before it happened. Nothing else that I can think of has changed.

Well, the search continues...

Well we are not alone untitled, this problem has been going around the forums for some time. Even with very experienced growers. But no one has come up with a clear answer or solution. Symptoms the same, bent broken new leaves,stunted growth, only a small proportion of plants effected.

Concensus seems to be it looks like a calcium deficiency but is happening in tanks where calcium should't be an issue. This has led to various theories of either high levels of Potassium or Magnesium preventing uptake of Calcium. I've tried playing with the Potassium but nothing changed. Some say they've seen improvement with more Iron, most say better with Calcium Chloride addition even with an already good GH reading.

I've discussed with Tom and he suggested upping the Co2 and Magnesium (to rule out a deficiency there)for 3 weeks. Well 2 weeks in with more Co2 and Magnesium, thru Equilibrium which also has Calcium,also the TMG has a good kick of Mg it's worse.

All this doesn't really belong in this thread, but the problem does seem to increase as I add more Co2 ?! That phenonomen alone would suggest a deficiency, but when we know there's enough there, well maybe there is an interfernce with uptake of something some where. But what or how ?

It's not that much of a biggie, it only affects a few stems of certain species. But it does bug me and I'd like to get a fix on it. Nobody else probably even notices the couple of stems effected but to me they stick out like a sore thumb.

Your post ruled out a couple of things for me. You use Ro water. I use Indonesian tap (pH 7.5, KH 4, Gh 13, no3 2-5ppm). I don't know exactly whats in it, I do know I can't drink it ! As such I never use a water conditioner, as I don't think they much in the way of chlorine and such. I was wondering if I should use a conditioner in case there's something in the water like chlorine or chloramine. You've seen both with and without tap.

Also I was wondering about the TMG. Flourish has a wider range of micros in it. Wondered if the TMG was missing something. You've tried both. Rules that out.

I'm going to try the counter-intuitive and add some Calcium Chloride, even with my 13dGH water and see if it has any effect.

I just have a feeeling that with the way this is happening to people with well run tanks, it's nature of appearing months into a tank with little change in the routine, and it's come and go nature, that there's an important lesson to be learned from it.

Hope Ingo and Tetratech aren't reading this - donm't want their resolve to waver on the nutrient dosing

Last edited by bensaf at 28-Sep-2005 22:11

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Cubha is a damn weed, all my tanks grow it big fat and fast, the larger 350 gal have it almost 6" across, less branching.

The issue now that you have resolved the CO2 for the 100 liter tank can easily be addressed:

Do this:
50% weekly water change
Add KNO3, 1/4 teaspoon,KH2PO4 1/16" teaspoon 4x a week,
Add MgSO4/CaSO4 once a week, 1/4-1/2 teaspoon(50:50) or just a little(1/4 of MgSO4 if the Gh is higher than 3-4).
Traces: Flourish or TMG etc 5mls, 3x a week(on off macro dosing days)

Wait 2-3 weeks before changing the routine and see what you think.

CO2: 5 other folks tried it and reported much more prounced intense pearling, better growth rates, less algae etc.

Pretty much the same thing I saw.

I know when I see a dramatic change and only a very few things can do this.

Regards,
Tom Barr

www.BarrReport

Tom,

This is more or less what I'm already doing for a while now... only thing I don't add is MgSO4 or CaSO4, but I do use Equilibrium. The Ludwigia used to be my most beautiful plant, but it's not anymore as it looks quite poor at the moment. I should have more than enough of everything as I add a bit more than you've suggested (it was definitely not enough for my plants)... I'm totally clueless about this. I keep trying to think what I'm doing differently now than to what I used to do in the past when everything was okay, but I've not come up with anything yet.

only thing I don't add is MgSO4 or CaSO4, but I do use Equilibrium

The Equilibrium is MgSO4 and CaSO4, with a lot of Potassium and some FE.

According to the label the porportion of the MgSO4 is higher then the calcium. Not sure if it works out that way when dissolved. I think a lot of MgS04 actually only adds a relatively small amount of ppm compared to some of the other chems.

Anyway as I mentioned I tried using the Equilibrium but things seem to get worse.I'm going to try adding the components invidually, starting with the calcium, and see if I can find something.

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Some days you're the pigeon and some days you're the statue.

Remember that age and treachery will always triumph over youth and ability.

Add more CO2, add the above nutrients, clean filters etc, prune, clean the tank, vac the gravel in 1/4-1/2 sections over 2-4 weeks.

Plants grow for defined reasons and tap water differences can influence some growth of certain species, but this is seldom the case with 99.5% of the plants and needs to be very carefully ruled out before concluding that is it.

It's not due to hard/soft water issues. The big huge plants I have in the 350 has a GH 160ppm and a similar KH.

So you can rule out nutrients fairly easily, the rest will be light/CO2, light is fairly easy to rule out, simply have enough.

So CO2 and work and patience is all that's left.

It's not some "special needs" plant, there are no such plants. I've grown 250-300 or species and have not found one yet, except with some special crypts, but that is an issue of emergent vs submersed growth.


Regards,
Tom Barr

www.BarrReport.com
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