Persistent GDA on plants

[RickyV]

Hello UKAPS! I recently made my first post on here on the CO2 thread asking about optimizing the CO2 in my tank. This post was made because I am assuming my GDA was in part due to improper CO2. However after making some changes such as, reducing temp from 28C to 25C, reducing light intensity from 100% to 50% (3 Chihiro's WRGB II pro 90), increasing CO2 injection, and increasing fertilization, I still have not seen much of an improvement on the GDA.

From what I understand algae growing on plants means they are unhealthy and leaching NH4 which the algae eats. So I need to figure out what is wrong with my plants. I am guessing I either still do not have enough CO2, or I am not fertilizing enough.

The low CO2 seems unlikely, because my drop checker is lime green at lights on, and it is getting close to yellow at the end of the photoperiod, if I increase the CO2 injection just a little bit my fish will start breathing really heavy, and I have plenty of flow as I have a 20000 LPH pump (though I guess low flow areas are still possible). I am getting a pH probe to get a better idea of the CO2 levels.

As for fertilization I am dosing the fertilizer in the pictures below, it says to dose 5 ml per 20 gallons(75 liters). I am dosing slightly under this at 80ml daily for total system volume of 1325 liters (350 gallons). I do the weekly 50% water changes. It is possible I should be dosing a lot more for my plant mass, I am not sure.

Here are some pictures of my plants, as you can see they all have a bit of GDA on them. The plants that have the most obvious sign of deficiency is the amazon sword, and the the Brazilian pennywort as the new growth looks really pale but maybe it is normal. The rotala bushes were recently trimmed.

 

[MichaelJ]

Hi @RickyV,
I am not a CO2 user, but I think there is still a good chance this is (still) a CO2/flow/nutrient distribution issue. Only based on a rough off the top of my head calculation, assuming 50% Weekly WC, I think your dosing is probably ok, but I also don't think you will go wrong by increasing it a bit and see how that goes as you do have a fair amount of plants there and it is a high tech tank. Again, I am not a CO2 expert, and I am sure some of our CO2 experts will chime in.

Cheers,
Michael

 

[RickyV]

My pH pen just arrived and the pH of the tank halfway in the photoperiod is 6.15, the pH of my tapwater is 7.7. I'll check the pH tomorrow throughout the day to know how much my pH drops and changes throughout the day.

 

[Witcher]

However after making some changes such as, reducing temp from 28C to 25C, reducing light intensity from 100% to 50% (3 Chihiro's WRGB II pro 90), increasing CO2 injection, and increasing fertilization, I still have not seen much of an improvement on the GDA.

Hey @RickyV what's your water parameters in general? Hardness, Ph, NPK and Fe to name them first? I doubt you re-mineralize RO etc for such a large quantities so assuming it's a tap water.

Your plants look generally healthy (no melting etc) but with obvious algae which are a chancers so if it was my tank I'd lower the amount of CO2 and ferts (but really difficult to estimate how much without knowing water parameters at the first place) and keep the light (and probably temp too) on the high side - both high light and high temp increases metabolism in plants (both lower and higher) which will help with quick depleting of nutrients otherwise available for algae. Higher plants have greater capability of storing nutrients than algae so in the race for food former will win.
Ps. Mg which can be seen as an ingredient of micros on your 2nd image of ferts is not a micronutrient so I'd think twice before using ferts from the company stating sth like that. Probably low amount of Mg can be also contributing to the problems but again - difficult to say without knowing your water parameters.

 

[RickyV]

Hey @RickyV what's your water parameters in general? Hardness, Ph, NPK and Fe to name them first? I doubt you re-mineralize RO etc for such a large quantities so assuming it's a tap water.

I do use tap water, below is the water report from a year ago. I will need to test the current parameters in my tank and get back to you. Tomorrow is actually water change day so it will be the perfect day to test. I will need to get a test kit for K, and Fe. Tomorrow I will test the pH before CO2 on and at lights on and at different points in the day to give you guys a better idea of the CO2 levels in the tank.

 

[erwin123]

Normally, I would say that you should remove the algae-infested leaves - on the assumption that the leaves with algae are unhealthy and they are unlikely to 'recover' The plant will be focusing its energy on new growth and letting these unhealthy leaves rot.
But this is a big tank and there seem to be a lot of affected leaves....

Another possibility would be to do a 72-hour blackout which is very effective in my experience in eliminating GDA. This is in effect a 'reset' of the tank. It does not mean that algae won't come back, but at least it gives your plants a 'head start'....

 

[RickyV]

Another possibility would be to do a 72-hour blackout which is very effective in my experience in eliminating GDA. This is in effect a 'reset' of the tank. It does not mean that algae won't come back, but at least it gives your plants a 'head start'....

Yeah I do try to remove the really bad leaves at during each water change, but as you said essentially all my plants are affected lol. I have considered a black out. I was just afraid it might not be effective for the algae and also harm the plants in the process. But it sounds like 3 days without light should not affect plants much.

 

[plantnoobdude]

reduce co2 first…
increase ferts (maybe) @MichaelJ
BUT NOT MICROS!!
Those micros are already very high and if you need more, you should probably venture into other mixes, or complimenting the mix with other salts.
A lot of your pics show very clear chlorosis. Fe, Mn and Mg are the cause here. I would try other compounds such as Fe dtpa, Eddha, Gluconate. I’ll tag in some friends here who have some experience with harder water and high tech @KirstyF @Hufsa

Your dose is currently 0.5 Fe weekly. I dose 0.0875 Fe weekly in my high tech. When I used to dose my APFUK mix, I always had issues with chlorosis, but I even tried up to 1ppm Fe with no improvement. At this point I was desperate, so I would try anything. I decided to start making my own micros at a very Low level compared to before (1ppm Fe to 0.1ppm) believe it or not, all symptoms of chlorosis disappeared. I have pictures of this, and have posted them somewhere on this forum. I use DTPA Fe now, but my tanks have quite soft water, so that is sufficient, for more advice on chelates and hard water.. I would ask kirstyF!

Perhaps adding Mg will help, but I feel it won’t take the tank all the way to where you want it.

So to conclude.

Bump up macros (probably not needed)
Lower co2
Touch up Mg
And fiddle with different chelates in your micro nutrients
(If you need advice I am more than happy to help!)

 

[dw1305]

Hi all,

A lot of your pics show very clear chlorosis. Fe, Mn and Mg are the cause here.

Because your water is relatively calcium (Ca) rich nutrient deficiencies involving magnesium (Mg) and iron (Fe) are more likely. Looking at the water report I'm going to guess you have enough manganese (Mn) and magnesium (Mg), although adding some more magnesium definitely wouldn't hurt. You also have a lot of sodium (Na), but there isn't a whole lot you can do about that.

I think there are signs of chlorosis (in the new leaves) as well. It is very likely to be iron (Fe) deficiency, because it is the new leaves that are affected and that means a non-mobile element .

Have a look at <"Frogbit taken a turn"> and <"FE EDDHA">.

cheers Darrel

 

[jaypeecee]

Mg which can be seen as an ingredient of micros on your 2nd image of ferts is not a micronutrient so I'd think twice before using ferts from the company stating sth like that.

Hi @Witcher
For a similar reason, I'd be concerned about the Macros separately listing P and PO4. Also, N and NO3. The Micros bottle also states DGH of 0.02 ppm/degrees. Very odd.
JPC

 

[plantnoobdude]

Hi @Witcher
For a similar reason, I'd be concerned about the Macros separately listing P and PO4. Also, N and NO3. The Micros bottle also states DGH of 0.02 ppm/degrees. Very odd.
JPC

Why?
The N-NO3 conversion is correct at about 4.4
And the P-PO4 conversion is correct at around 3.

I suspect the dgh of 0.2 is how much will be supplied by the fertiliser? (I’m guessing from the small amount of Mg)

 

[RickyV]

A lot of your pics show very clear chlorosis. Fe, Mn and Mg are the cause here. I would try other compounds such as Fe dtpa, Eddha, Gluconate.

This makes a lot of sense since pale new growth has been pretty prevalent. For some reason I just assumed it was normal and thought the leaves would darken as they age, but they only degraded which made me think it was a macro deficiency. I see now it is very clear this is iron deficiency.

Have a look at <"Frogbit taken a turn"> and <"FE EDDHA">.

Interesting reads, learned a lot! So from what I understand although plants need very tiny amounts of iron, because my water is hard almost none if any iron is available to my plants, hence the Fe deficiency. So It seems a chelator will help with this, it looks like the two recommended ones are DTPA and EDDHA. EDDHA causes a tint in the water which I would not like so DTPA should be fine right?
According to the dosing calculator I only need 2.41 grams of Fe DTPA 11% for 1325 liters (350 gallons) to raise the Fe by 0.2ppm. Is this a good target?

For a similar reason, I'd be concerned about the Macros separately listing P and PO4. Also, N and NO3. The Micros bottle also states DGH of 0.02 ppm/degrees. Very odd.
JPC

Interesting I did not catch this. NilocG is pretty popular here in the US and I have only heard good things which is why I went with them. They do sell some Fe DTPA NA IRON CHELATE SELECT SALTS (FE)

 

[dw1305]

Hi all,

...... So from what I understand although plants need very tiny amounts of iron, but because my water is hard almost none if any iron is available to my plants, hence the Fe deficiency. So It seems a chelator will help with this, it looks like the two recommended ones are DTPA and EDDHA. EDDHA causes a tint in the water which I would not like so DTPA should be fine......

That is it.

The other thing I should have said is that it is <"only new leaves">, grown after iron (Fe) deficiency is <"no longer limiting growth">, that will be green.

That was one reason I originally used Lemna minor ("Duckweed") for the <"Duckweed Index"> (I now prefer <"Amazon Frogbit"> (Limnobium laevigatum)), it has a <"very quick turn-over of leaves">.

Interesting reads, learned a lot!

You might be interested in <"MG/FE deficiency in S. Repens and Rotala Indica"> & <"Duckweed Index says Nitrogen please?">.

cheers Darrel

 

[RickyV]

You might be interested in <"MG/FE deficiency in S. Repens and Rotala Indica"> & <"Duckweed Index says Nitrogen please?">.

Thanks will take a look at them.

Looks like CO2 may not be as high as once thought. Here are the readings so far in the day,
8:00 am pH 7.4 CO2 Turns on
9:00 am pH 6.85
10:00 am pH 6.68
10:30 am pH 6.61 Lights on

 

[jaypeecee]

Why?
The N-NO3 conversion is correct at about 4.4
And the P-PO4 conversion is correct at around 3.

I suspect the dgh of 0.2 is how much will be supplied by the fertiliser? (I’m guessing from the small amount of Mg)

Hi @plantnoobdude

I should have made myself clearer.

I'm not questioning the conversion. All that was necessary from the manufacturer was to provide nitrogen and phosphorus figures for NO3 and PO4. This is what the aquarist wants to know. And, is the General Hardness of this fertilizer 0.02ppm or 0.02 degrees? I'm not sure why this figure is quoted on the bottle because both figures are very low and of little relevance. Or, am I overlooking something?

JPC

 

[MichaelJ]

General Hardness of this fertilizer 0.02ppm or 0.02 degrees? I'm not sure why this figure is quoted on the bottle because both figures are very low and of little relevance. Or, am I overlooking something?

Hi @jaypeecee , The bootle says ppm/degrees. Only degrees apply to the GH. The minerals you add with this Micro/Trace product (predominantly the 0.11 ppm of Mg) will indeed add ~0.02 GH (0.11 / 4.34 ~= 0.02) to the water based on the dosing recommendation, but putting it on the bottle is obviously utterly superfluous as you said.

Cheers,
Michael

 

[LMuhlen]

It might be that the supplier is informing that it won't increase the GH significantly, since it may be a concern of their clientele that a fertilizer would increase the GH undesirably. So they are stating, it only increases 0.02 dGH, no need to worry.

 

[RickyV]

I felt like I should start a journal on this tank so I will be posting updates on how the plants respond to the iron DTPA and magnesium there. 1200L High Tech Planted Tank

 

[jaypeecee]

You also have a lot of sodium (Na), but there isn't a whole lot you can do about that.

Hi @dw1305 & @RickyV

Is it not possible to 'dilute' RickyV's tap water to lower the sodium level? I just had a quick look at a typical range of sodium figures for my tap water here in the UK. The range is 19 to 38 mg/litre. RickyV is seeing 33 to 81 ppm. Ricky, are you on well water? I ask because I see that you are in Texas.

Of course, dilution may be easier said than done. Would the use of RODI or rainwater be a viable option? Of course, in saying this, sodium may not be the culprit. There is not a lot of readily-available information about the effects of sodium on aquatic plants. But, I'll dig a bit deeper.

JPC

 

[jaypeecee]

Hi @jaypeecee , The bootle says ppm/degrees. Only degrees apply to the GH. The minerals you add with this Micro/Trace product (predominantly the 0.11 ppm of Mg) will indeed add ~0.02 GH (0.11 / 4.34 ~= 0.02) to the water based on the dosing recommendation, but putting it on the bottle is obviously utterly superfluous as you said.

Hi @MichaelJ

Thanks for clarifying what I was trying to say. Good on ya!

JPC