Can't grow healthy stargrass

[dealt]

Hi. For the past 3 months I've been struggling to improve my stargrass' condition but I can't seem to get it right. Here's what it looks like now:

I've already increased my daily dose of ferts for the past 2 weeks:
15ml KN03
9ml KH2P04
4ml K2S04
Trace

Tank size is 36x18x16in. Lights are 2x55w PL with reflectors. Pressurized C02. I've no problems with algae, just plants showing signs of nutrient diffeciency: (cracked leaves on wisteria, l. aromatica, etc; pale green color of broad leafed plants). I'm suspecting light distribution since there are noticable "dead spots" on my tank with my current lighting setup. Any suggestions? Thanks!

 

[VaughnH]

How did you mix the liquid solutions of KNO3, KH2PO4, K2SO4? Without knowing how much of each fert is in those solutions I don't know if you are dosing too lightly or too heavily or just right. Do you use a drop checker to make sure you have enough CO2?

 

[dealt]

Hi, here's the guide that I followed:

Potassium nitrate - 40g to 500ml of water
Potassium Phosphate - 15g to 500ml of water
Potassium Sulphate - 55g to 500ml of water

 

[creighton]

Do you add Mg?

 

[Tom Barr]

Looks and sounds like CO2.
This is a fast growing weed, so is L aromatica.
As such, they tend to compete with eachother.

For CO2, for nutrients etc.

So if run things lean, you can run into this more, some suspect plant = plant interactions.

I did in the past but later found it was one plant needed more than the other it's rather obvious once you think about, that some plants are better at getting a limited supply under some conditions than others.

So adding a non limiting supply resolves this issue.

Note, if you are CO2 limited, adding more PO4 is not going to resolve the issue.
Likewise, if you are say NO3 limited, adding more CO2 is not going to help either.

So you need to be sure you are non limited for each nutrient, do water changes, clean and keep up on the tank's maintenance well. If you still are having issues, go back through the CO2/nutrients again and reset things again and add a bit more to see each time.

We all have similar issues over time, we all think our CO2 is fine and then have issues only to learn and see later, it was CO2, or we under dosed.

Adding something like ADA Aqua soil + water column ferts gives you more confidence and is easier to dose because the dosing routine compliments the other.

You can simply use a dosing calculator to find what you are adding for N, P, K, Ca, Mg, Traces. Then make sure you do water changes and dose frequently to keep them in the non limiting range. From there, you tweak and really focus on CO2.

Adding CO2 and messing with that should be done when you have a few hours to be around the tank to see how the tank responds.

If the CO2 system is good and well designed, you should see pearling and dramatic growth improvement within 1-2 hours or so and it should stay that way or grow even better as the day progresses.

Adding CO2 mist and good current also can help a great deal.
Rarely is a problem related to low light, this is fairly low light tolerant plant as well.

Regards,
Tom Barr

 

[dealt]

Looks and sounds like CO2.
This is a fast growing weed, so is L aromatica.
As such, they tend to compete with eachother.

For CO2, for nutrients etc.

So if run things lean, you can run into this more, some suspect plant = plant interactions.

I did in the past but later found it was one plant needed more than the other it's rather obvious once you think about, that some plants are better at getting a limited supply under some conditions than others.

So adding a non limiting supply resolves this issue.

Note, if you are CO2 limited, adding more PO4 is not going to resolve the issue.
Likewise, if you are say NO3 limited, adding more CO2 is not going to help either.

So you need to be sure you are non limited for each nutrient, do water changes, clean and keep up on the tank's maintenance well. If you still are having issues, go back through the CO2/nutrients again and reset things again and add a bit more to see each time.

We all have similar issues over time, we all think our CO2 is fine and then have issues only to learn and see later, it was CO2, or we under dosed.

Adding something like ADA Aqua soil + water column ferts gives you more confidence and is easier to dose because the dosing routine compliments the other.

You can simply use a dosing calculator to find what you are adding for N, P, K, Ca, Mg, Traces. Then make sure you do water changes and dose frequently to keep them in the non limiting range. From there, you tweak and really focus on CO2.

Adding CO2 and messing with that should be done when you have a few hours to be around the tank to see how the tank responds.

If the CO2 system is good and well designed, you should see pearling and dramatic growth improvement within 1-2 hours or so and it should stay that way or grow even better as the day progresses.

Adding CO2 mist and good current also can help a great deal.
Rarely is a problem related to low light, this is fairly low light tolerant plant as well.

Regards,
Tom Barr

Hi sir. Thanks a lot for the very comprehensive response. To summarize what you said, do you suggest to keep increasing my dosage of fertz (along with stable c02 supply) until my plants gained improvement? Should I do this on a weekly basis? Will plants respong in a weeks time? Thanks again!

 

[VaughnH]

How much CO2 are you getting into the water? You can measure this with a drop checker, but not by any other inexpensive test. You haven't said yet if you use a drop checker, nor if you do, how you use it.

 

[dealt]

How much CO2 are you getting into the water? You can measure this with a drop checker, but not by any other inexpensive test. You haven't said yet if you use a drop checker, nor if you do, how you use it.

Hi! Sorry, but right now I've no way of measuring C02, I just increase the bps rate, added another powerhead, make sure that there is visible c02 mist around the tank and the water surface is not broken. I'm thinking of buying a c02 test kit. Would you rather suggest to use a drop checker than test kits? Drop checkers are the ones placed inside the tank and displays color indicators based on PH levels right? Can I get exact measures of C02 there? Thanks!

 

[VaughnH]

You can't get an exact measure of CO2 by any method accessible to us. But the drop checker, used with known KH distilled or DI water in it, gives the best accuracy of any method that is accessible to us. If you are experienced enough you can probably judge how much CO2 you have by just watching the plants, but I'm nowhere near that experienced, so I need a method to actually measure what is there. And, the drop checker is that method.

What Tom was saying is that you most likely don't have enough CO2 in the water, or your tank water circulation isn't good, so some plants never see much of the CO2. The drop checker at least gives you a rough idea if you have enough.