Does this look like potassium deficiency?

YodelMogul said:

What do you think about low nitrates though? I’ve asked myself that question in the past and decided to just leave it alone rather than to dose nitrates.

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Sorry for the late reply. zero ammonia, nitrite and nitrate is not good. All zeros mean you plants are consuming all the nitrogen in the water So theirmaight not be enough to satisfy the plants. And if nitrogen is insufficient plant will not consume any other nutrients which could build up to toxic levels. I would recommend you always have a small amount of measurable nitrate in the water.

After I first setup my tank I had no plant growth. I din't understand it. I saw a phosphate test kit at the store and bought it hopping it would provide a clue. when i ran the test it was offf scale high (over 30ppm). I eventually figured out is was nitrogen and added nitrogen to the tank. Phosphate then started to drop and my plants started to grow.

Steven F said:

I eventually figured out is was nitrogen and added nitrogen to the tank. Phosphate then started to drop and my plants started to grow.

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Or, you could just feed your fish more often. Isn't "nitrogen" just a fancy word for fish poop?

New leaves look good. Prune off the old affected leaves.

Be very careful adding that much potassium sulfate (K2SO4). Bacteria in the soil convert sulfates to toxic H2S, which can kill plant roots. Use KCl (potassium chloride) sold in grocery stores as a "salt substitute. And you don't need 20 ppm K. That high level is probably for high-tech tanks with CO2 injection and very rapid plant growth.

That said, the added K didn't solve your "holes in the leaves" problem, so I would either stop or reduce the K dosing.

Stem plants don't do that well in Walstad tanks. If your only problem is a few dead Hygrophila leaves, I would consider your tank a success.

Nice tank!

You can get Potassium gluconate as well in the health drug section.

mistergreen said:

You can get Potassium gluconate as well in the health drug section.

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I can vouch for that. The tablet form made measuring pretty easy and the 99mg of crushed powder added to my 8 gallon bowl completely reversed the hole phenomenon in my lotus leaves. It also resulted in an algae bloom, but that was relatively easy to bring under control (the bladder snails took it in stride.)

johnwesley0 said:

I can vouch for that. The tablet form made measuring pretty easy and the 99mg of crushed powder added to my 8 gallon bowl completely reversed the hole phenomenon in my lotus leaves. It also resulted in an algae bloom, but that was relatively easy to bring under control (the bladder snails took it in stride.)

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Interesting about the algae. You can probably insert part of the tablet into the soil under the lotus like a root tab, reducing the chance of algae.

Btw, someone on this forum pointed me to this nutrient calculator, I've been using it to calculate dosage for chelated iron: https://rotalabutterfly.com/nutrient-calculator.php. There's a nifty option to specify using a "solution" that lets you specify the size of the container you're mixing in and the amount you want to does to reach a target. In the DIY ferts list you can specify KCl to figure out just how much you need to mix to reach a specific ppm.

Maybe overkill in this case, if it's a one-time dose. But still a helpful site nonetheless

dwalstad said:

Be very careful adding that much potassium sulfate (K2SO4). Bacteria in the soil convert sulfates to toxic H2S, which can kill plant roots. Use KCl (potassium chloride) sold in grocery stores as a "salt substitute. And you don't need 20 ppm K. That high level is probably for high-tech tanks with CO2 injection and very rapid plant growth.

That said, the added K didn't solve your "holes in the leaves" problem, so I would either stop or reduce the K dosing.

Stem plants don't do that well in Walstad tanks. If your only problem is a few dead Hygrophila leaves, I would consider your tank a success.

Nice tank!

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Thanks for the advice I will discontinue unless the other plants begin to show holes again. I was under the impression that plants consumed a decent amount of the sulphur and was improving the dose to see if the holes would eventually stop. I guess the hygro just isn’t my thing

jatcar95 said:

Btw, someone on this forum pointed me to this nutrient calculator, I've been using it to calculate dosage for chelated iron: https://rotalabutterfly.com/nutrient-calculator.php. There's a nifty option to specify using a "solution" that lets you specify the size of the container you're mixing in and the amount you want to does to reach a target. In the DIY ferts list you can specify KCl to figure out just how much you need to mix to reach a specific ppm.

Maybe overkill in this case, if it's a one-time dose. But still a helpful site nonetheless

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Yes I found this somewhere and was using it. This is a really great tool!

So I’m still unsure does weekly dosing of either kcl or k2so4 lead to problems without doing water changes due to accumulation of chloride/sulphate. Some say the chloride is negligible and some say the sulphate is. I’ve seen many more people recommending k2so4 over kcl…

Also, is it safe to fertilize my tank with kcl with emerald corys (brochis splendens)?

YodelMogul said:

So I’m still unsure does weekly dosing of either kcl or k2so4 lead to problems without doing water changes due to accumulation of chloride/sulphate. Some say the chloride is negligible and some say the sulphate is. I’ve seen many more people recommending k2so4 over kcl…

Also, is it safe to fertilize my tank with kcl with emerald corys (brochis splendens)?

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One dose should go a long way for potassium deficiency. When I was having a problem, the pinholes ceased with subsequent new growth.

johnwesley0 said:

One dose should go a long way for potassium deficiency. When I was having a problem, the pinholes ceased with subsequent new growth.

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okay I guess I’ll sit back and monitor for awhile then. Particular fast growers (hygro and wisteria) didn’t seem to respond very well to K dosage so maybe something else is up.