I'm dosing ei but still trying to figure out my dosing regimen on my 32g. Now my hygro is developing small brown spots that turn into holes. What kind of deficiency is this?

CO2

I have a client that called me out to check his tank he'd been doing EI with for a long time. We looked at the dosing log, nothing out of the ordinary.....

The tank was perfect the last few months.

I looked under the tank.........the pump driving the CO2 reactors was unplugged. Apparently the last week's water change had the CO2 system unplugged for cleanign but forgot to switch it back "on".

Opps!

The tank looked pretty good for being a high light packed tank without any added CO2 for a week. Excel is dosed 2x a week, so that likely helped.

But.........back to your issue, the Giant Hygro all had holes on some of the leaves.

I've seen this consistently and many folks think it's K+, however, K+ is added in the form of GH booster and KNO3, to at least 6x what would be required vs N.

So I'd have to use up all the N @ 6x the rate relative K+ before K+ would be an issue............that's not happening.
Stunted tips, browning, rotting etc, species express their dislike for non stable or sudden low CO2 many ways.

I know this plant and several others very well in terms of deficiencies.
Algae, and plants are better test kits once you know and have confirmed the cause.

Regards,
Tom Barr

Hi,
This could either be a potassium or a nitrogen deficiency so at least more KNO3 is called for. According to nutricalc (v1.9.3) a 32 usg has a baseline dosing of:

3X per week
-----------------
3/8 teaspoon (1.7 gram) KNO3
3/32 teaspoon (0.5 gram) KH2PO4
1/8 teaspoon (0.8 gram) KSO4 if needed
7/8 teaspoon (4.5 gram) MgSO4 if needed

1/8 teaspoon (0.3 gram) dry CSM+B or (6 ml TMG) alternate days to macros.

These are such irritating fractions that I would increase the dosage by just doubling everything and round to the nearest easy measurement, really. 1/2 of this, 1/4 of that. There is no need to sweat over 1/32's of teaspoons, which you couldn't eyeball with any accuracy if your life depended on it anyway.

Trim all affected leaves and monitor for 2-3 weeks. I'm assuming the holes appear on older leaves, not new leaves right?

Cheers,

Ok. It's not a symptom of a calcium deficiency, is it? That's the only thing I'm not dosing. In the meantime I'm going to start dosing 2x/week just to see what happens. I was only dosing 1x/week before.

Co2 is probably an issue because I had co2 up to a couple of weeks ago. But I want to go non-co2 on this tank, it's getting to be too hit or miss trying to keep the co2 going, I'm fraught with problems with co2 lately. I would think that this would be possible somehow? Will the plants just adjust to a lower co2 rate after a while? Or are they simply going to die without co2? I only have 38 watts of lighting on this tank anyway so co2 is not really needed in that regard.

I also have cuttings from these very same hygro plants in a non-co2 tank. They are doing fine so far (it's been three weeks since I removed them).

No, this is a CO2 issue, I know this plant, know this deficiency.
Been there, done this, I lost count now.......

I've confirmed this many times.

Regards,
Tom Barr

The issue is not from going from one method in a stable tank to the other.
Plants will adapt well.
But rather, switch back and forth between high/low CO2, DIY folks have many issues with that. They bob between high CO2 and low.

That's a big issue.

Plants want stability. Some plants, are very aggressive with getting the CO2, other's grow slower to make up for it, so some may not do well with some plant combos.
This is not allelopathy, it's competition between plants for nutrients(NO3, CO2, light etc). Pruning some back well can help.

You can remove some plants or prune them back a bit and the others will start to grow well.

Regards,
Tom Barr

Couldn't this problem be due to the fact that the when the hygro was in a higher CO2 environment it didn't need much rubisco, and now that it is in lower CO2 environment it needs time to develop some?

If so, until that happens, it will show signs of CO2 deficiency until it adjusts.

Bill

That's what I was wondering about too. The worst affected leaves are coming off so I'm removing them from the tank as needed. It's mainly the leaves closest to the light, probably the ones who are more limited by co2 than lighting I'm thinking (since it is a low light tank).

Yep, the plant appears to drop those leaves and eat's the reserves from some leaves, yet leaves soem alone. It takes about a week for the adjustment, up to 3 weeks in some cases.

While the plant needs time to develop, it still needs more RUBISCO, but it need Carbon skeletons to make that.

If carbon is limiting, the time required is longer.

The plant is not N or P or K+ or trace limited though.
The plant likely takes the carbon, the sugars, the starch etc from certain leaves and translocates it to the new shoots/leaves.

I see many new side shoots comiung up when I've done this.

These tend to be resisent to low CO2.
But we already know there's more RUBISCO in leaves grown under low CO2 vs non limiting high CO2.

Regards,
Tom Barr

Regards,
Tom Barr

This makes sense, some of the leaves appear totally unaffected yet some are totally disentegrated. I did a big clean up today removing dead or dying leaves and a bunch of roots. I can't figure out why the plants insist on throwing off roots into the water column and aren't anchoring themselves in the substrate much at all. You would think that after 6 weeks there would be some anchoring happening but there's not. Any particular reason for this? I don't seem to have this problem in my 10g that has cuttings from this tank.