Can't sort out wat deficiency this is. Pls help.

[rusticdr]

This a 100 g planted tank with co2 injection and being lighted for 6 hrs.. I dose reduced ei based on long term observations of nitrate and phosphate levels. Water s RO to which I add seachem equilibrium with each water change. My dosing is like this
Macro..
10 tsp of kno3 + 2 tsp of kh2po4 dissolved in 600 ml of water
10 tsp of mgso4 + 3 tsp of k2so4 dissolved in another 600ml of water.
I dose 30 ml of each on alternate days.. Mon Wed and friday

Micro.
Seachem flourish and iron .. 8 ml on alternate days tuesday and Thursday.

I initially wasn't dosing k2so4 bit thinking there may be a shortage of potassium I started with that. And my original phosphate dosing was 4 tsp which I reduced as my readings showed between 5 and 10 ppm.

My current reading of nitrate and phosphate s 40 and 2 ppm respectively.

If u see the pics..
1. The anubias s showing some gsa and some holes in the older leaves. New ones seem ok
2. Hygrophila polysperma s turning yellow involving both old and new with some curling of new leaves.
3. The floating frogbits r showing Brown spots and resorption with friable leaves which fall off easily.
My thoughts: maybe phosphate. Yellowing and resorption of leaves along with focal gsa.

So can anyone shed some light. Thank u.

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[zozo]

Could be potassium, dry necrotic spots is typical early sign for that, in aquatic plants these are the spots that obviously can't dry, but melt away or get eaten by shrimp and snail and turn in to holes.

Here you see several stages of K deficiency. Note the simularities with your floater.

 

[rusticdr]

Ok.. I have just started dosing k2so4 this week. Let's c whether the situation changes. I have increased the kh2po4 by 2 spoons today in the original mix. So keeping fingers crossed. Most plants r doing reasonably well with a bit of green string algae which I keep removing by hand. Flow s decent with two powerheads and a wavemaker.

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[rusticdr]

Update.. I have increased my co2 delivery from 2bps to 4bps with co2 coming on 2 hrs before lights on and going off 1 hr prior to lights off. Apart from this I have started dosing k2so4 5 tsp in 600 ml of water dosed 30 ml on alternate days. I think I may have Magnesium toxicity leading to Ca def seen as smaller leaves with curling of leaves. I know this can also be caused by co2 deficiency but I was overdosing magnesium. So have corrected both. Let's c. Any thought on that?
Besides I have also noticed that my frogbits leaves r somewhat smaller now that before. Can that be attributed to defective calcium uptake too?

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[dw1305]

Hi all,

I know this can also be caused by co2 deficiency

I don't know what the answer is, but if you look at the older leaves on the <"Amazon Frogbit">, they are looking distinctly un-happy, so it isn't CO2 deficiency. This was why I choose a floating plant (with access) for the Duckweed Index it takes CO2 deficiency out of the equation.

I think I may have Magnesium toxicity leading to Ca def seen as smaller leaves with curling of leaves

Calcium deficiency effects younger leaves (it isn't mobile within the plant), but plants don't need very much calcium, as you are adding the <"Seachem Equilibrium"> I'd be surprised if it was a calcium issue.

You could try not adding any magnesium (other than via the "Equilibrium") and see what happens.

Have you measured the pH? I've found that <"Hygrophila corymbosa"> doesn't like really soft water, and your H. polysperma looks a bit pale, and you don't seem to be adding any carbonate buffering (dKH) at all? If you want to try adding potassium bi-carbonate (KH2CO3) is cheap (250g is ~£4) and easily obtainable (via Ebay etc.).

cheers Darrel