Plants Yellowing and Failing to Thrive in High Tech Setup

[McGodes1990]

Thanks for your input everyone. Today, I'm going to set CO2 on 30 mins earlier and take another pH profile as per Zeus's suggestion.

One molecule of chlorophyll contains one part of Mg and 4 parts of N - that means that with your CO2 and 15ppm of Mg floating in the water plants cannot produce enough chlorophyll due to lack of available Nitrogen - that's why they move N from older leaves to new ones trying to compensate lack of it in the water, and that's why your green plants do melt.

So Witcher, you're suggesting that this regime is dosing too much Mg? I actually wasn't adding any Mg to my Macros until very recently and unfortunately had the same poor health plants. I was simply relying on whatever Mg Equilibrium provides. Does excess Mg increase the demand for Nitrate hence causing a deficiency? Regarding my red plants, A.R. is generally ok by my Rotala Macandra has never displayed red.

I do agree that these excessive water changes I've been doing twice a week can be tough on the system. Those have been out of necessity because of the algae. I'm gonna try and resist the urge to clean things up and keep it to once a week now. The increased CO2 and lower lighting should hopefully help with that.

 

[Nick72]

....
Quick look at your dosing regime (I've rounded the numbers from @Zeus. calc):
23ppm NO3 = approx 5ppm of N weekly
15ppm of Mg weekly
.

Sorry @Witcher but you've miss read the Nitrate numbers.

The OP is adding 7.5ppm three times a week. That's 22.5ppm per week of Nitrate, which is inline with standard E.I. Dosing.

15ppm Mg would also be the correct weekly dosage.

 

[Witcher]

Sorry @Witcher but you've miss read the Nitrate numbers.

Hi @Nick72 , no, I've only rounded them for easier calculation:

Quick look at your dosing regime (I've rounded the numbers

from 22.7ppm of NO3 to 23ppm and from 15.2ppm of Mg to 15ppm.

23ppm of NO3 (Nitrates) is approximately 5ppm of pure Nitrogen.

Also, if we assume that water is 8GH and we have 15ppm of Mg in it, it means there is approx 32ppm of Ca in the water, so we have proportions of 1:2 Mg:Ca. That's in my opinion too much of Mg in relation to Ca anyway.

@McGodes1990 - yes, I think there is too much of Mg, personally I'd reduce it by 50% or even more.

 

[JoshP12]

Hi @McGodes1990,

You have probably done this, but it might be a good idea to flush out the filter tubes + intensely clean out the filter!

Josh

 

[Nick72]

.......

Quick look at your dosing regime (I've rounded the numbers from @Zeus. calc):
23ppm NO3 = approx 5ppm of N weekly
15ppm of Mg weekly

One molecule of chlorophyll contains one part of Mg and 4 parts of N - that means that with your CO2 and 15ppm of Mg floating in the water plants cannot produce enough chlorophyll due to lack of available Nitrogen - that's why they move N from older leaves to new ones trying to compensate lack of it in the water, and that's why your green plants do melt.
.......

@Witcher

Ok. We can agree that 23ppm NO3 is equivalent to 5ppm NO3-N.

Which is also the E.I. Standard dosage for NO3-N,

The OP is getting readings of 40ppm+ using a Nitrate test and is dosing NO3 to E.I. Standards.

Mulder's Chart does not indicate Mg as a blocker for Nitrogen.

So I can't follow your thinking that the OP's tank is nitrogen deficient.

 

[Nick72]

.

....

Also, if we assume that water is 8GH and we have 15ppm of Mg in it, it means there is approx 32ppm of Ca in the water, so we have proportions of 1:2 Mg:Ca. That's in my opinion too much of Mg in relation to Ca anyway.

@McGodes1990 - yes, I think there is too much of Mg, personally I'd reduce it by 50% or even more.

.....

I agree in regards to ratio of Ca/Mg, but as OP will have correct levels of Mg at 15ppm per week, I would advise adding 4.88g (1 heaped tsp) of CaSo4.2H20 (Gypsum) per week. This will raise Ca to 47ppm and therefore restore the Ca/Mg ratio, and ensure that the plants are not either Mg or Ca deficient.

 

[McGodes1990]

Ok so here's today's (the evening of 5/20) update with the pH profile. Today I switched CO2 on 30 mins earlier as per Zeus's recommendation.

Here is the pH profile:
10:45am - 7.4 (pre-CO2)
12:00pm - CO2 kicks on
12:30pm - 7.2
1:00pm - 6.8
1:30pm - 6.6
2:30pm - 6.6 (light on)
4:30pm - 6.4
6:00pm - 6.4
8:00pm - 6.4
8:30pm - CO2 off
9:30pm - 6.4
10:30pm - light off
11:30pm - 6.6

 

[McGodes1990]

**1 Week Later Update**
So this week the adjustment I have made have been to CO2, lighting, and nutrients. 6 days later, as I write this, I've noticed moderate improvements in the plant grown. Here are the details, my observations, and some pics.

Changes:
-CO2 now turns on 30 mins earlier (2.5 hours before light turns on)
-Lighting intensity reduced to 40%
-10g of MgSO4 dry dosed on Day 1 (Macro mix now includes MgSO4 so that it will be added with the ferts instead of dry)
-Water changes reduced from 2x 80% per week to 1x 50% per week.

Today's tank parameters:
GH: 13
KH: 6
NO3: 40ppm

Plant Observations:
-The growth rate appears to be increased. I'm specifically seeing increased growth rates on the eleocharis and the S. Repens. The new leaves look clean and are much more in the direction of the color they should be (check the original post for a comparison to today's pics)
-While the rotala macandra is always the fastest grower, it has significantly increased it's growth rate with some leaves reaching nearly the top of the tank. New growth is clean and green. Once conditions are stable and algae free, I'll work on bringing out the reds in those bad boys. For now I'm happy with no algae.
-I spot dosed all the cyano at the beginning of the week with H2O2. I'm pleased to say that it has not come back in a significant quantity. This is a huge improvement for me because in the past I would treat it and it would come back usually in 48 hours or so.

Moving forward:
Now that I have added the 96g/500mls of MgSO4 to my macros, I will no longer add 10g dry in the beginning of the week. Tomorrow, I do the 50% water change and will clean the lily pipes and inflow/outflow tubes. I'll trim off any weak/BBA infested leaves.

Let me know what you guys think and if you have any additional suggestions/conclusions.

 

[Nick72]

Your tank is looking great!

Very pleased you are seeing some improvement, but it's early days -keep an eye on it.

Try not to change anything else for a few weeks so you can really see the effects of your changes.