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Discussion Starter · #1 · (Edited)
Hi all,

So I have a tank where I am trying tocover the surface with dwarf water lettuce. I figured I’d buy a few and let it spread like crazy since I had done that successfully in the past 8 years or so ago on the same tank. However, it was high tech then and now it’s low tech. Almost everything submerged is struggling hard with CO2 deficiency, but what shocks me is that the floaters are struggling just as hard, with leaves rapidly yellowing from the tip and then melting away. There is stunted new growth, but it’s at a rate which matches the melting rate such that there has been no net increase in floater mass for months now. Since these are the only non-CO2 limited plants in the tank, I thought it’d be super easy to grow them, but they are still struggling hard. Any ideas?

Some Relevant Details
Tank volume: 55G
Tank age: 10 years
Light: 1x T5HO 28” above substrate, ~70 mm PAR to floaters, ~15 mm PAR to substrate, on for 7.5 hours per day
CO2 supplementation: none
Dosing: tried half of high tech EI with dry ferts for a few weeks, but currently using 15 squirts of Easy Green per week with 1 tbsp GH booster and 1.5 tsp MgSO4.7H2O on water changes; osmocote root tabs in substrate regularly
Test readings: Only have a API nitrate test kit right now, uncalibrated reads are 40-80ppm nitrate. I need to make some stock solutions but have checked that my tap reads at 0ppm. Pretty confident I'm not low (or at least not zero) on nitrates, plus I'm dosing some and have such struggling plant growth overall that I'm sure not much is getting taken up.
Water change: 50% weekly
Flow: ~8x tank volume, but keep floaters in a ring of tubing to prevent them from getting swept around
Stocking: 1 Harlequin Rasbora, 3 Amano shrimp, lots of pest snails like MTS
Other observations: lots of tiny white bugs in my aquarium, not sure what they are but there might be thousands; I think they are seed shrimp so not too concerned

Pic is attached.

Also, not sure if this could be helpful, but my other plants are listed below. I recently cut my lighting from 20-25 mm PAR at substrate to ~15 mm PAR to try and fight the CO2 deficiency.

Plants struggling with slow and poor growth:
Anubias nana barteri
Amazon Sword
Echinodorus ‘rose’ Sword
Chain Sword (E. tennellus)
Cryptocoryne wendtii
Brazilian Pennywort
Jungle Val

Plants not struggling:
Red Tiger Lotus
Java Moss
 

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Very interested in reading the answer. My water lettuce is hanging in there but so far (more than a month into) not propagating. It grew one leaf but shed off two in the beginning, so it's surviving but not thriving.
 

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So a couple of things.

The first is that the picture does not show dwarf water lettuce. Looks like salvinia to me. It should grow quite well once adapted to your water conditions. Presumably the ring is preventing them from being tossed around in your tank?

Secondly, 15 par is very low. I sincerely doubt you are experiencing a co2 deficiency, this is just a low tech tank is all. I would increase it back to the 25 par at substrate level.

Thirdly, your fertilizer is crazy high. Easy green doses per 10 gallons. So 15 pumps is 150 gallons dosage. PLUS you are dosing magnesium sulfate for some reason? Plus you are dosing a GH booster? Easy green is an all in one EI style fertilizer. You definitely do not need magnesium sulfate at all and might not need GH booster (what is your tap water gh? and what is your tank water gh after water change?)

My guess is your plants are struggling because nutrients are bonkers super duper high. Depending on base GH you might be making your water into liquid rock. Soooo yeah. If it were me I would 1) do a +90% water change once per day for 2 or 3 days. Then I would dose easy green per directions (so 5 pumps, not 6 and certainly not 15), Then I would figure out your tap water gh, kh, tds, and ph. This will be important in figuring out what plants might struggle at baseline.

Hopefully this is helpful.
 

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Discussion Starter · #4 · (Edited)
@minorhero Thanks for the thoughts; I appreciate the help. To answer your questions:
  • I've never seen salvinia in-person (unless these are it), but my impression from pictures is that salvinia leaves aren't smooth and have ridges on them. This was sold to me as dwarf water lettuce, but you could be right. Nevertheless, still want to solve the deficiency problem. Yes, the ring is to prevent them from getting blown around the tank by the water flow. It works super well.
  • Have not tested these in awhile, but my tap GH is ~3-4 degrees and my KH is ~2 degrees.
  • Dosing a little GH booster with my 50% weekly water changes because it won't really hurt and I have some shrimp in the tank, although I haven't always regularly dosed it in the past and they have not died (they are all 10 years old, actually).
  • I am dosing extra MgSO4 just to ensure that what I was seeing wasn't a magnesium deficiency but more likely a CO2 deficiency for the submerged plants. I know that a Mg deficiency is unlikely but I also haven't measured how much of the hardness is comprised of Ca vs Mg. My water isn't incredibly hard to start with. Not super tied to continuing to dose it, but that's why I have been dosing it.
  • I'm dosing a lot (basically following the high light, high tech tank Easy Green dosage to make sure I cover all nutrients at an adequate level) to "eliminate" nutrient deficiencies from the equation, basically the same as Tom Barr's EI philosophy even though low tech uptake is way less. A couple things make me really skeptical about the "liquid rock" theory:
    • The 50% WC weekly (sometimes slightly more than that) prevents the nutrients from rising to more than 2x the dosed levels
    • I just add the GH booster and Mg with the water change to slightly raise the hardness of my incoming water; I don't dose it without a 50% water change
    • I calibrated my nitrate test kit, and my tank is coming in between 10 and 20 ppm nitrates after the latest WC, so if that is a proxy of other nutrient levels, they are probably not incredibly high
However, I'm not really dismissing the "nutrients are super high" theory you brought up since I know there can be toxicity at certain levels (a lot have been posting anecdotal evidence of trace toxicity in EI dosing). Since it's been a few weeks of dosing like this without seeing much improvement, I'm going to pull it back to the normal low tech dosage like you suggested to see if things improve. I lowered my lighting at the same time, so I won't be able to attribute it to one thing or another, but the latest leaf of growth on my Amazon sword has been almost entirely hole-free in the week since I lowered the lighting, so I'm hesitant to reverse it. I didn't want to lower it quite that much but I'm somewhat adjustability-limited. At the old lighting level, even Anubias had large holes in new growth, and the crypts were developing pinholes with both brown and black borders on older leaves before they melted off. The new growth on pennywort was also severely stunted at the previous lighting level, although I'm not sure it will grow at all with lighting this low now. If it was indeed nutrient toxicity and growth improves, I could try to reverse the lighting afterwards.

So a couple of things.

The first is that the picture does not show dwarf water lettuce. Looks like salvinia to me. It should grow quite well once adapted to your water conditions. Presumably the ring is preventing them from being tossed around in your tank?

Secondly, 15 par is very low. I sincerely doubt you are experiencing a co2 deficiency, this is just a low tech tank is all. I would increase it back to the 25 par at substrate level.

Thirdly, your fertilizer is crazy high. Easy green doses per 10 gallons. So 15 pumps is 150 gallons dosage. PLUS you are dosing magnesium sulfate for some reason? Plus you are dosing a GH booster? Easy green is an all in one EI style fertilizer. You definitely do not need magnesium sulfate at all and might not need GH booster (what is your tap water gh? and what is your tank water gh after water change?)

My guess is your plants are struggling because nutrients are bonkers super duper high. Depending on base GH you might be making your water into liquid rock. Soooo yeah. If it were me I would 1) do a +90% water change once per day for 2 or 3 days. Then I would dose easy green per directions (so 5 pumps, not 6 and certainly not 15), Then I would figure out your tap water gh, kh, tds, and ph. This will be important in figuring out what plants might struggle at baseline.

Hopefully this is helpful.
 

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@minorhero Thanks for the thoughts; I appreciate the help. To answer your questions:

  • I've never seen salvinia in-person (unless these are it), but my impression from pictures is that salvinia leaves aren't smooth and have ridges on them. This was sold to me as dwarf water lettuce, but you could be right. Nevertheless, still want to solve the deficiency problem.
  • Have not tested these in awhile, but my tap GH is ~3-4 degrees and my KH is ~2 degrees.
  • Dosing a little GH booster with my 50% weekly water changes because it won't really hurt and I have some shrimp in the tank, although I haven't always regularly dosed it in the past and they have not died (they are all 10 years old, actually).
  • I am dosing extra MgSO4 just to ensure that what I was seeing wasn't a magnesium deficiency but more likely a CO2 deficiency for the submerged plants. I know that a Mg deficiency is unlikely but I also haven't measured how much of the hardness is comprised of Ca vs Mg. My water isn't incredibly hard to start with. Not super tied to continuing to dose it, but that's why I have been dosing it.
  • I'm dosing a lot (basically following the high light, high tech tank Easy Green dosage to make sure I cover all nutrients at an adequate level) to "eliminate" nutrient deficiencies from the equation, basically the same as Tom Barr's EI philosophy even though low tech uptake is way less. A couple things make me really skeptical about the "liquid rock" theory:
    • The 50% WC weekly (sometimes slightly more than that) prevents the nutrients from rising to more than 2x the dosed levels
    • I just add the GH booster and Mg with the water change to slightly raise the hardness of my incoming water; I don't dose it without a 50% water change
    • I calibrated my nitrate test kit, and my tank is coming in between 10 and 20 ppm nitrates after the latest WC, so if that is a proxy of other nutrient levels, they are probably not incredibly high
However, I'm not really dismissing the "nutrients are super high" theory you brought up since I know there can be toxicity at certain levels (a lot have been posting anecdotal evidence of trace toxicity in EI dosing). Since it's been a few weeks of dosing like this without seeing much improvement, I'm going to pull it back to the normal low tech dosage like you suggested to see if things improve. I lowered my lighting at the same time, so I won't be able to attribute it to one thing or another, but the latest leaf of growth on my Amazon sword has been almost entirely hole-free in the week since I lowered the lighting, so I'm hesitant to reverse it. I didn't want to lower it quite that much but I'm somewhat adjustability-limited. At the old lighting level, even Anubias had large holes in new growth, and the crypts were developing pinholes with both brown and black borders on older leaves before they melted off. The new growth on pennywort was also severely stunted at the previous lighting level, although I'm not sure it will grow at all with lighting this low now. If it was indeed nutrient toxicity and growth improves, I could try to reverse the lighting afterwards.
If you dump the extra stuff and just do the normal dosage of easy green with nothing else added I think you will find things coming back into balance pretty quickly. 3-4 gh is great for pretty much anything, you do not need gh booster. BUT making your water too hard will stunt most plants.

50% water change is not a particularly high amount of water to change. For any EI dosing regime its really the minimum. I do at least 70% once a week and sometimes can get it up to 80 or 90% depending on the tank and its configuration.

Out of curiosity, what do you mean when you say you calibrated your nitrate test kit? Are you using liquid tests or something else?

Also, how are you measuring par? Is the 15par you are referring to in the middle, the corners? Or is the 15 par just an estimate based on size of light and distance?
 

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Discussion Starter · #6 ·
If you dump the extra stuff and just do the normal dosage of easy green with nothing else added I think you will find things coming back into balance pretty quickly. 3-4 gh is great for pretty much anything, you do not need gh booster. BUT making your water too hard will stunt most plants.

50% water change is not a particularly high amount of water to change. For any EI dosing regime its really the minimum. I do at least 70% once a week and sometimes can get it up to 80 or 90% depending on the tank and its configuration.
Yeah I hope so, although I started dosing because these symptoms were there before any dosing in Jan/Feb, so we'll see what happens. Since then, I have raised the light 8 inches and also added a layer of window screen in between to bring it to where it is now. Hopefully the tank is in a better state now than back then (it was coming off of a ~3-4 year period of neglect, although java moss, anubias, and crypt growth was better in those conditions than it seemed after cleanup, both before and after dosing started). The GH booster only brings up the hardness a little bit, so it's still well within conditions that plants would like. I agree that 50% isn't a super high level of water change but it does provide a ceiling for how high the tank's nutrient levels can rise to, barring high levels of anything in your tap.

Out of curiosity, what do you mean when you say you calibrated your nitrate test kit? Are you using liquid tests or something else?

Also, how are you measuring par? Is the 15par you are referring to in the middle, the corners? Or is the 15 par just an estimate based on size of light and distance?
I'm using the API nitrate test, so it's a liquid test. I calibrated by making reference solutions with known concentrations from KNO3 and distilled water and running the test on each solution before comparing to my tank's test color.

For PAR, I am measuring using the Photone app for iOS. Obviously, I did not dunk my phone into the water, so I measured the PAR at the top of the tank near where the floaters are (~60 mm PAR) and then projected the curve out based on how far the lights were from that point and how much further it is down to the substrate. It's just an estimate so it's got decent error bars around it, but qualitatively it feels decently dim in the tank, and with 1 T5HO bulb 28" above the substrate and a window screen in between, I'm pretty confident it's not over 20 mm PAR unless there's some magic going on. That reading is in the middle of the tank. As you move out to the left and right edges where there's not as much light around it, it drops off pretty substantially. I must be getting like ~10 mm PAR at the ends of the tank near the substrate. I only have Anubias, crypts, and a sword out there right now, and the sword still put out a new leaf in the last week, so there is still growth, and like I said, it's not riddled with holes like the previous growth. I'd love to find a way to raise the lighting a bit, since the rate of growth is probably going to be pretty glacial at this lighting level, but I'd rather have slow growth than poor growth. I'll give it some time to see what happens before making a change.
 
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