I've got a problem with my 20 gallon excel tank which I converted from a Walstad type tank about 2 months ago. I'm getting very little growth for the most part, I have an H. difformis which looks wilted and growth is pretty much stunted all around. I see no yellowing of leaves or signs of decay. I do 50% water changes/week. Gh is 3.

I dose the following for 20 gallons:

excel - per instructions
tropica - 2 ml x2
k2so4 3/8 tsp x1

I had to stop dosing N and P because my levels have been running very high. I'm currently adding K2SO4 since I'm not dosing KNO3. I don't believe I'm overfeeding or am overstocked. I suspect there may be some other nutrient problem intefering with N uptake, but I don't know what it might be. Calcium, Mg ? I thought this sort of stunted growth woul indicate a Macro nutrient problem. I'm stumped.


Henry

Your tank sounds very much like the 10 gallon I posted about

What is the substrate?

How much light?

And, how did the soil-based tank work for you?

Bill

My substrate is eco complete. Light is 2.2 watts of NO flourescent. I have never used soil as a substrate.

Henry

It's been a long day. Light is 2.2 watts/gallon of no flourescents.

So what about the water changes and what about the Excel dosing rates?

Try doing 50-70% weekly water changes, dose the KNO3/KH2PO4/Traces Excel.
Assume a 1/3 the EI dosing rates.
Add 1.5 labeled rate for the Excel.

Regards,
Tom Barr

I have always done 50% water changes. I will try 1.5 rec. dose for excel My nitrates were always well in excess of 40 ppm just prior to water change when dosing. Phosphates have never tested lower than 1.5 ppm when dosing. I use Lamotte tests and also tested with a hobby kit. N and P are always high no matter what test I use.

I am not a priest in the Walstad religion nor am I a purist in most things, but if you ". . . never used soil as a substrate . . " then you did not have a Walstad-type tank. Soil substrates are basic to the Walstad approach.

Bill

It sure seems like your plants are starved for something. You have plenty of light, a good substrate, and Excel works as a carbon source, so if I were you I would try dosing KNO3 and KH2PO4 for a month, just to see what happens. With only Excel for carbon the plants won't grow at top speed, so you won't need the full EI dosage of any fert, but dosing half that amount should work, if that is the problem.

You are correct. I used the term loosley. I was referring to Tom's article regarding non co2 tanks.

Henry

Thanks,

I am sometimes amazed at my own ineptitude at keeping plants. I'm not sure if I have the skills to do this. I must say Tom has done a great deal to help people like me who have the black thumb of death. I've had some successes, but I seem to go endlessly from one problem to another.