# Plant Suffers as CO2 Rises



## k-maub (Feb 10, 2007)

Hello all.

My tank was on a tear a couple months ago with no algae problems whatsoever when I noticed my CO2 diffuser had been clogged and was not actually operating as it was supposed to. Any CO2 going into the tank was simply diffusing through the lines, but water was not circulating to create turbulence and maximize dissolution.

Well, I had to fix that, but I feel that my tank has not been doing as well since (even though CO2 is up to 25 ppm -- 13 Kh, 7.2 pH). This makes me think I am nutrient-limited somehow. Unfortunately, all I can test for reliably is nitrates and phosphates (both are plenty high).

I dose by the EI method, and in addition to KNO3 and KH2PO4, I add K2SO4, Plantex CSM+B and MgSO4 (all from Greg Watson), dosing alternate days of macros and micros. I think that covers everything but calcium. On the one hand, I feel like my water is hard enough that surely it has enough calcium in it. On the other hand, a lot of the twisted new growth problem I am having makes me suspicious calcium is a problem. Just for grins, I have been adding pieces of calcium supplements tablets that claim to have calcium carbonate in them, but I'm not really sure how much of that goes to the water column.

The symptom, besides twisted new growth, has been seeing the foxtail needles die in older parts of the plant farther than 1", say, of the tip (so there's just a little healthy section of the plant near the end of it), plus it's just not growing as fast as it had been. The water sprite, on the other hand, has been pearling like crazy, and the bacopa leaves are growing a little flatter and healthier looking (they sometimes curl up a good bit).

So basically, can anyone identify the nutrient I'm missing? I'm willing to buy calcium from Greg if need be. I'm also suspicious, because I've heard about the important of a Mg/Ca ratio being maintained for proper nutrient uptake.

Any help would be much appreciated!


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## mpe1329 (Sep 1, 2007)

I'm a plant newbie, but:

1. Probably a really stupid question, but you do dose Fe, right? I assume you do, but did not see it on your list of ferts. 

2. Is it past time for (a) a bulb change or has anything happened recently to decrease amount of light or (b) a water change or filter cleaning?

3. Besides the CO2, have you added anything new to the tank recently, like a rock or driftwood? 

Answer Key
1. This guy is a moron.
2(a) The Battle of Hastings in 1066.
2(b) Because God loves me.
3. Only a 12" Silver Dollar Fish?, but I'm sure that's not the problem.


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## k-maub (Feb 10, 2007)

1) Plantex actually has iron in it, although after reading the ingredients list again, I probably don't need to be dosing MgSO4, since Mg is in Plantex as well.

2) If anything, I now have more light, because I switched out two out of four bulbs for (identical) new ones at the same time I cleaned out my CO2 reactor. I'm changing water every week per the EI method.

3) Nothing else added to the tank lately.

I'm still suspicious about some kind of Ca/Mg imbalance, mostly because I have no idea how that works, and I have no way of knowing how much I have of either.

On the other hand, I read something Barr wrote about Plantex iron being less stable than Tropica, and perhaps it is wise to dose that every day. I'll probably give that a whirl for now since it's an easy thing to try.


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## Wö£fëñxXx1 (Feb 10, 2005)

You can grow plants just fine with plantex, you can buy the expensive stuff if you want, but it is not necessary.

You left out some info, filter/media, tank size, amount of light etc. but not needed anyway 

If you are dosing NPK and TE, then you are not having a nutrient deficiency, what you are having is a mis-understanding of what is going on within the enclosed eco system.

Clean the diffuser every week, I keep an old coffee canister with bleach water in it, when lights go out day before water change pull the diffuser and soak over night, rinse well after water change and install.

Make sure you are getting good flow _throughout_ the tank, this is vital, *pay attention to the plants*, as you are noticing now that they are not doing well, you will notice when they are, NPK TE good C02 with good filter/media. and *good flow*.
Raise spray bar or lily pipe at lights out for surface aeration.
It is that simple!


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## k-maub (Feb 10, 2007)

Yes, I'm sorry. 30 gallon tank with a HOB Aquaclear filter (just a sponge and ceramics media, no carbon), and the diffuser is just some PVC fed by a small Rio pump.

I actually wouldn't be surprised at all if I'm not getting flow to all the right places. I don't aquascape so much as I try to grow a veritable jungle. So, I'm all for more flow in the tank; but as it is, my spray bar is pretty powerful so that it kind of blows over any plants that get in its way. What's the best way of getting uniform circulation, then? Can it be done with one flow input (not counting the HOB filter)? I'm like to get water circulating everywhere, but as far as I can figure out, it's hard to achieve without knocking plants over. Perhaps if I setup the spray bar at the back of the tank instead of the side?

Thanks for the help thus far!


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## hoppycalif (Apr 7, 2005)

Getting good water circulation to all parts of the tank is very difficult. First canister filters come with a limited length of hose, so you either stay within the area the hoses will reach, or you buy some longer hoses for more flexibility in locating the inlet and outlet. Then, the canister filter comes with a return system that isn't optimum for much of anything, and the spray bar that comes with some filters isn't likely to be the exact length you want. And, the filter inlet fitting is almost always just a open pipe with a screen over it, collecting water at one location. I have tried making my own spray bar and spray bar type filter inlet, but that didn't work out very well either. Then, you have to compromise between getting enough velocity of flow from the spray bar so it can move water all the way across the tank, but not so much it digs holes in the substrate or blows the plants and fish all over the tank.

This was a long way to say you just have to experiment with different setups until you seem to be getting the best circulation through as much of the tank as you can get.

Of course, then the plants all grow lush and the added plant mass ruins the circulation pattern! Isn't this fun???


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## ponyrandy (Jan 13, 2007)

For good circulation check out the spray bar I made:
http://www.aquaticplantcentral.com/...quarium-projects/43188-diy-hob-spray-bar.html
I drilled the holes to point downward and I put plenty of them in it so that the circulation would be uniform over the whole tank, then I just ran the pickup tube straight down the middle. I am very pleased with this setup. I am running an Eheim 2234 in a 25 gallon and with all of the holes in the spray bar you don't see any plant movement and the surface has no ripples, yet I get circulation across the whole length of the tank. 
Brian


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## hoppycalif (Apr 7, 2005)

It is actually better to have some slight ripple on the top water surface to increase the rate of oxygen dissolving into the water. You lose a little CO2 this way, but very little.


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## k-maub (Feb 10, 2007)

Hoppy, presumably my HOB filter is disturbing the surface enough to keep oxygen up at night? I mean, I'm guessing unless you have a canister filter, the spray bar need not ripple...

Ponyrandy, that's a neat setup; I suspected a spray bar on the back may be a good idea. In your thread, people talked about discoloration. Have you seen this? Is is a pleasant, obscuring discoloration, or a slimy, needs to be cleaned every week thing?

Thanks.


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## ponyrandy (Jan 13, 2007)

Well, its been almost a month now and I don't have any discoloration at all. With as many posts about discoloration I was certainly expecting something. I know the fish aren't keeping it clean because I never see any up there. 
Brian


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