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Too much fertilizer.

ForestDave

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12 Nov 2020
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Forest of Dean
Hi.
I thought I'd take the sometimes-given advice to put a small handful of Osmocote underneath my substrate when setting up the tank. I estimate I put about 17g over a 40x100cm base. The base has inch-high gravel/egg crate plastic keeping the rocks off of the glass and the substrate is about 3" to 4" deep. This was obviously too much as some fast-growing stem plants like Hygrophilla sp difformis and Pogosternon erectus are growing really slowly and don't look particularly happy. Ludwigia repens diamond red is growing although I cut the top half from one stem the other day and stuck it in the substrate only for it to wilt as I presume it hit a hot spot of fertilizer. On the plus side Hygrophila polysperma and Rotala H'ra are happy, although the latter is bright green and has no hint of redness. The tank overall is looking ok although it's aquascaping masterpiece or anything. My 30 shrimp and 2 nerite snails are perfectly happy. My rabbit snails don't look happy and are not as active as they should be though as I think they are hit with the over-fertilized substrate the most.

Is there a way out of this mess, please?

I am EI dosing at the moment and adding CO2 using a reactor.
-Could I stop EI dosing for a while and allow the plants to use up the excess ferts in the substrate or would the epiphytes not get enough fertilizer?
-Would the ferts gradually dissipate over time or will the Dennerle scapers soil aqua soil retain the ferts as they are not being used because of the EI dosing?

I really, really don't want to rescape if possible, if there is any other way to sort this you would make my year!
Cheers
Dave

I'll post a tank shot in a minute. The Rotala and ludwigia repens were cut last week and is not that high at the moment.
 
A few tank shots.
 

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Unhappy Ludwigia Repens and Pogosternon erectus.
 

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Thanks Darrel, that gives me hope!

The TDS rises about 10 points per day and resets to about 230-250 after a 50% w/c. Tap water is about 150 TDS.

Thanks
Dave.
 
Your TDS rise is likely to be from the stone combined with the lower pH from CO2 injection.

I'm going to put my neck on the line, and suggest that the issues you are encountering are unrelated to the Osmocote underneath the soil, unless you can actually measure an excess of ammonia levels which I would assume is not the case as you'd see issues with your shrimp and snails.

Irrespective of the cause, the solution is likely to be the same - large daily water changes, correct level of CO2 and good CO2 distribution.
 
I am EI dosing at the moment and adding CO2 using a reactor
-Could I stop EI dosing for a while and allow the plants to use up the excess ferts in the substrate or would the epiphytes not get enough fertilizer?
-Would the ferts gradually dissipate over time or will the Dennerle scapers soil aqua soil retain the ferts as they are not being used because of the EI dosing?
The TDS rises about 10 points per day
Hiya mate. there shouldn't be an issue with too much ferts as such so I would look at why the fauna isn't happy which could be more likely the co2. If there is excess ammonia it should only become toxic when the PH rises above neutral.
If you are concerned about too much ease back on the E.I dosing. Dosing at E.I levels if you are including magnesium in the mix will raise the TDS by about 10ppm per day anyway and if your plants don't need it because there's plenty already the TDS will just continue to rise. The epiphites will be fine, all the nutrients under the soil will eventually end up in the water column. The only issue you have is Osmocote isn't really intended for use in aquariums so the ratios we usually mix E.I at will differ from the Osmo. Generally speaking Osmo is usually high in ammonia and phosphate, the ammonia rapidly breaks down in to Nitrate. With good plant growth which you should get with co2 the excess will deplete quite rapidly.
If it were me I would keep the planting dense, even throw in a few floaters to mop up the excess and maybe just dose Traces. pottasium and magnesium for a while. All substrates wear off over time, even the ADA stuff which comes loaded with nutrients wears off and you have to add more. AFAIK Tropica doesn't contain any it's just quite good at retaining some which is a good thing over the long term.
 
Hi all,
The TDS rises about 10 points per day and resets to about 230-250 after a 50% w/c. Tap water is about 150 TDS.
No, that sounds fine. You don't <"need many ions"> to make the conductivity rise much more than that.
........ If you can get pure NaCl? You need 0.491g (491mg) L-1 NaCl to give a 1000 µS standard.
cheers Darrel
 
Your TDS rise is likely to be from the stone combined with the lower pH from CO2 injection.

I'm going to put my neck on the line, and suggest that the issues you are encountering are unrelated to the Osmocote underneath the soil, unless you can actually measure an excess of ammonia levels which I would assume is not the case as you'd see issues with your shrimp and snails.

Irrespective of the cause, the solution is likely to be the same - large daily water changes, correct level of CO2 and good CO2 distribution.
Thanks Wookii.
It could be flow. I have a full width spray bar and an FX6 filter. I felt the flow wasn't reaching behind the large rocks very well. I thought that I would rectified this by drilling a few holes underneath the spray bar at an angle so not only does the spray bar jet the water towards the front but also straight down at an angle all the way across. I now see the benefits of a good circular flow when hardscapes are involved.
I've had plant root failures all around the tank though, so maybe it was CO2 although I'm getting a consistent 1ph drop now and the gas is fully dissolved with no bubbles so I'm hoping that piece of the puzzle is fixed. My basic NT labs water tests rate Nitrate/nitrite and ammonia at 0 and I'm doing 50% w/c twice a week at the moment. I'll keep on tweaking things!

BTW have you finished your muddy riverbank tank yet?
 
Hiya mate. there shouldn't be an issue with too much ferts as such so I would look at why the fauna isn't happy which could be more likely the co2. If there is excess ammonia it should only become toxic when the PH rises above neutral.
If you are concerned about too much ease back on the E.I dosing. Dosing at E.I levels if you are including magnesium in the mix will raise the TDS by about 10ppm per day anyway and if your plants don't need it because there's plenty already the TDS will just continue to rise. The epiphites will be fine, all the nutrients under the soil will eventually end up in the water column. The only issue you have is Osmocote isn't really intended for use in aquariums so the ratios we usually mix E.I at will differ from the Osmo. Generally speaking Osmo is usually high in ammonia and phosphate, the ammonia rapidly breaks down in to Nitrate. With good plant growth which you should get with co2 the excess will deplete quite rapidly.
If it were me I would keep the planting dense, even throw in a few floaters to mop up the excess and maybe just dose Traces. pottasium and magnesium for a while. All substrates wear off over time, even the ADA stuff which comes loaded with nutrients wears off and you have to add more. AFAIK Tropica doesn't contain any it's just quite good at retaining some which is a good thing over the long term.
Thank you.
That sounds like it's worth a shot. A few weeks back the tank was balancing out at 180 TDS so it is slightly creeping up. I'll try just dosing traces for a while.

The shrimp are happy and my nerites are always active. The bigger rabbit snails aren't that active though, although one of them hasn't been great for a couple of weeks since I tried to pull it off the glass and didn't have the technique weighed off. Its colour has become darker and it looks unhealthy. I also lost 4 nerites bought about a month ago which I thought was either CO2 related or cheap EBAY glutaraldehyde related. They tended to drop off the glass towards the end of the CO2 cycle and lay upside down. I'm pretty sure I am on it with the CO2 now hopefully and I stopped with the "Aqua C" liquid carbon as it was making the shrimp sluggish and sent them into hiding. I'm hoping to not need the liquid carbon or if I find I do I'll splash out on some Excel.
Cheers!
Dave
 
If those tests are to be trusted, 0 ammonia suggests it's not excess ferts causing your livestock problems, but 0 nitrate could be the cause of your plant problems.
Thanks Sparkyweasle.
I usually test just before a water change as a sanity check. I say zero nitrates but there is usually the tiniest hint of pink which is difficult to see. I’ll check after fertiliser are added and see how that changes over the day.

One thing that is confusing me is the d/c. When I measure the ph drop and take it down by 1 ph, this is taking about 2 hours atm. At that point the D/c is still not lime green, I presume because you need to wait another 2 hours for it to catch up. I’m turning my lights on based on the ph drop and not waiting for a lime green d/c. Does this make sense, or should I wait for the d/c too?
Cheers!
 
My basic NT labs water tests rate Nitrate

As @sparkyweasel says, that is your answer right there, assuming the test kit isn't lying to you. Assuming you are currently on a weekly water change schedule, if you are dosing EI, you should have a significant buildup of nitrate by the end of the week - part of the purpose of the large water change at the end of the week is to somewhat reset this build up.

If you are seeing such low nitrates (and nitrate test kits are notoriously unreliable) you could well be running out of other essential ferts.

You mention dosing EI, but what are you using for ferts, and how much are you dosing?

BTW have you finished your muddy riverbank tank yet?

No not yet. Still waiting to get a few ducks in a row before attempting that - it may take a while!
 
Cheers Wookii.
I've been dosing the basic APF EI mix, 40ml on alternate days with a rest day once a week. I am doing a w/c every 3 or 4 days and up to a couple of weeks ago, it was every 2 days. The tank was scaped on the 19th Feb although I had the plants in a bare tank for 3 or 4 weeks before that and some were not looking that great after that. I keep meaning to borrow my daughter's PC and use the nutrient calculator as it won't format on my crappy Chrome book. What is the typical level of nitrate build-up I should look out for?

Good luck with the new scape when you get those ducks sorted!
 
Cheers Wookii.
I've been dosing the basic APF EI mix, 40ml on alternate days with a rest day once a week. I am doing a w/c every 3 or 4 days and up to a couple of weeks ago, it was every 2 days. The tank was scaped on the 19th Feb although I had the plants in a bare tank for 3 or 4 weeks before that and some were not looking that great after that. I keep meaning to borrow my daughter's PC and use the nutrient calculator as it won't format on my crappy Chrome book. What is the typical level of nitrate build-up I should look out for?

Good luck with the new scape when you get those ducks sorted!

OK, you may need to dose additional amounts when you make water changes, as that will be stripping a fair bit out. I do daily 25% water changes, and have to increasing dosing amounts by around 80% to compensate. Did you buy the measuring spoons with the APFUK kit? Also, I assume you mixed in the prescribed recipe?

  • 4tsp Potassium Nitrate
  • 1tsp Potassium Phosphate
  • 6tsp Magnesium Sulphate
  • 500ml Water

I only ask, as it's easy to make a mistake, and mis-count the number of teaspoons, or pick up the wrong measuring spoon (I've done it myself, picking up the 1/2 tsp measuring spoon, rather than the 1 tsp version).
 
OK, you may need to dose additional amounts when you make water changes, as that will be stripping a fair bit out. I do daily 25% water changes, and have to increasing dosing amounts by around 80% to compensate. Did you buy the measuring spoons with the APFUK kit? Also, I assume you mixed in the prescribed recipe?



I only ask, as it's easy to make a mistake, and mis-count the number of teaspoons, or pick up the wrong measuring spoon (I've done it myself, picking up the 1/2 tsp measuring spoon, rather than the 1 tsp version).
Thanks!
Yes, I'm using the recipe included with the kit and am using a cooking teaspoon to measure it out. How did you come to the 80% figure, by checking the TDS?
 
Thanks!
Yes, I'm using the recipe included with the kit and am using a cooking teaspoon to measure it out. How did you come to the 80% figure, by checking the TDS?

No, I did it all on a spreadsheet. I plotted the nutrient dosing under standard alternate day dosing and 50% weekly water change, and assumed no plant uptake to keep it simple, and plotted all the way until the nutrient level ready the same steady state accumulation figure at the end of each week - which takes around 60 days.

Then I plotted the same but with daily dosing, and daily water changes, and used Goal Seek to determine the correct daily dosing amount to hit the same steady state accumulation figure. So in essence I've just tried to convert standard EI alternate day dosing and once a week water change practice to daily dosing and daily water changes.

There are probably holes in the theory, and the way I've calculated it, but it seems to work okay, and in all honesty I could probably just have doubled the dosing and called it quits.
 
No, I did it all on a spreadsheet. I plotted the nutrient dosing under standard alternate day dosing and 50% weekly water change, and assumed no plant uptake to keep it simple, and plotted all the way until the nutrient level ready the same steady state accumulation figure at the end of each week - which takes around 60 days.

Then I plotted the same but with daily dosing, and daily water changes, and used Goal Seek to determine the correct daily dosing amount to hit the same steady state accumulation figure. So in essence I've just tried to convert standard EI alternate day dosing and once a week water change practice to daily dosing and daily water changes.

There are probably holes in the theory, and the way I've calculated it, but it seems to work okay, and in all honesty I could probably just have doubled the dosing and called it quits.
Thanks.
I'll up it by 50% for the next week and see how the plants respond and I'll look into the spreadsheet system when I have a bit of time.
Cheers
Dave
 
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