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Hygrophila Corymbosa 'Siamensis' (help)

6625 Views 9 Replies 7 Participants Last post by  captain_bu

A couple of weeks ago I bought plants. All the plants are doing well except the Hygrophila Corymbosa 'Siamensis'. They've all melted away. I thought Hygros are suppose to be the easiest to grow. The only thing I can think of is the lighting or the high temperature. But I actually bought them b/c they were suggested on Simply Discus as being able to tolerate the higher temps.

I'm kind of new to aquatic plants... I had an aquarium about 15 years ago and had Anarcharis, Elodea, and Hygros and they grew great. I think it was off a 40W bulb too in a 29G :/ So I really didn't think it would be a problem getting back into the hobby with them... in fact, I was more worried about the other plants...

Here is what I bought....

3 ea. Cryptocoryne Spiralis
4 ea. Cryptocoryne Wendtii Red
4 ea. Echinodorus Bleheri (Amazon Sword) SM
3 ea. Hygrophila Angustifolia
3 ea. Hygrophila Corymbosa 'Siamensis'
2 ea. Sagittaria Subulata (Dwarf)
1 ea. Spathiphyllum Tasson ( Brazil Sword) - I know this isn't really an aquatic plant and I plan to move it if it shows any signs of stress of dying. So far it looks healthy.

Tank Stats:
75G, 4x65W bulbs (3x10k and 1x Actinic bulb - although I'm going to replace the Actinic with a 12k).

PH 7.5-7.7
Hardness: Measures around 170-180 mg/L

Water Temperature: According the the thermometer it's 90F but according to the thermostat I have it set at 83F. I know I need to get a second thermometer to verify.

I also do a 25% water change every 2-3 days. I try to do it every other day but the last week I've done it every third day due to lack of time.

Fish: 5 Discus, 2 Corys, 2 Glow light tetras, and two nerite snails.

Thanks in advance,
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Hmm... well I thought I had posted this in the plants section... since I can't figure out how to delete...

I did some research and it might be a potassium issue.

I came up with three chemicals to dose it with.

1) Potassium Gluconate
2) Potassium Bicarbonate
3) Potassium Chloride

Which one is best? Using my basic chemistry background and what I could find on the net, they all have some benefits (I could be wrong).

#1) It could remove metals from the water. I don't think I have a problem with it though.

#2) It could add carbon dioxide to the water for plant growth?

#3) It could soften water, which discus prefer.

Are my conclusions wrong? Doing a search, apparently people use all of them. What are your thoughts?
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Potassium sulphate is what we normally use to add potassium without extra phosphorous.
In some cases that particular hygro plant is grown emmersed instead of submeresed and it will go through a bit of a melt before it gets its submerged growth. Yes that is a potassium demanding plant as well.
It's interesting you mentioned temperature. I've found a few aquatic plants that grow much better in my unheated grow out tank (And a few that won't grow at all.) where the temp fluctuates between 68 and 72 degrees F. My swords all melted at this temperature, but the Microsword grows like mad and Macrandra doesn't deteriorate like in my main tank.

I think 90 degrees is going to be pretty high for most plants. I'd trust the thermometer over the heater thermostat. I've found they are usually off on the heaters, but even cheapo thermometers don't vary by much IME.
x2 on what nemo said. if it was a K def you would more than likely seel pinholes in the leaves and they would fall off as opposed to melting on you.

if the switch from emersed to submersed isnt whats getting you i would say either the heat, you arent fertilizing or lack of co2.
x2 on what nemo said. if it was a K def you would more than likely seel pinholes in the leaves and they would fall off as opposed to melting on you.

if the switch from emersed to submersed isnt whats getting you i would say either the heat, you arent fertilizing or lack of co2.
Well, most of the hygros have melted away now, but there is one plant that is budding off new leaves. So we'll see... I'm also going to try potassium to see how that goes.

The other plants do pretty well. But I do know the Swords prefer higher temps.

As for potassium sulfate, doesn't that decrease the PH? Not a problem with Discus, but I would think that would normally be a problem? Is it generally cheaper?
Temperature is not a problem. Mine grows very well in a tank of 80F. Potassium sulfate is not supposed to change your pH. This plant likes a lot of light, otherwise the lower leaves will shed.
Hey, welcome to the forum.

Please check out to understand the basics of plant needs.


Basically, plants need nutrients, CO2 and light. If there is a lack of the 3 components, plants die... You have too much light and causes the other 2 to lack. Normally, 2x65W T5HO is all you need.

And don't trust the thermostat, trust the thermometer. 90F is awfully high. High temperatures also degas a lot of gasses like O2 for the fish and CO2 for the plants.
Normally, 2x65W T5HO is all you need.
The OP appears to be using PC lighting (4x65W) not T5HO. There are no 65W T5HO bulbs. 48" T5HO bulbs are 54W, 60" T5HO bulbs are 80W. If he has a standard 75 gallon tank his fixture is 48" long.

Agree that the OP needs to educate himself about the relationship between light intensity, CO2 and ferts. Also agree that the thermometer is a better indication of the temp than the setting on his heater.
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