liquid pond fertilizer & nitrates

Is that the Laguna pond water treatment stuff. If it is, then I've got some too. I haven't used much yet, but didn't see any problems when I did. But there are certainly people out there better equipped to anwser this than me.

The dosage suggests 50mL per 1000L, so I figure that that's about 1 mL per 5 gallons.

They definitely need it, but you probably don't need to adda any, your fish will produce enough nitrogen, most likely. So it's not really a "bad thing" just not likely to be limiting, so you don't want to add extra. Unless, of course, it is the limiting nutrient.

Plants need nitrogen. If your tests are showing readings of zero the plants are not getting enough unless the fish are providing just enough to support the need for this element.
How much of each element, plants need depends on many variables including, for example, light. More light creates faster growth and higher usage of various nutrients. So more may be needed.
If your plants are happy and growing well under their present circumstances, don't change anything. It is probably balanced.
Once you change one parameter, you disrupt that balance and this has the potential to cause problems.

Len

How much light do you have over the aquarium?
Tell us about your filtration, substrate, fish load and what, if anything you have been dosing out of your 'drugstore'.

I am not a big fan of any combo ferts that are not made expressly for aquariums. Yours may be just fine and it may not. It's a 'pond' fertilizer.
Getting the correct elements for your tank is not an expensive proposition and balancing it is not difficult as long as you have some patience.
Do a 50% water change(with tap water conditioner) and get back to us with the info. on your tank and we'll go from there.

Len

I think the advice annona gave you in the first thread was excellent. Don't know what I can add to that.
Just to reiterate:
With a 3watts/gal. you will definitely need to try to keep your CO2ppm as close to 25 as possible with your injection.
Don't use any chemicals to clear algae. Use elbow grease and water changes. BTW, a python would make the process of water changes much more simplified for you, and weekly water changes will do wonders for your tank.
Test kits needed are pH,kH,nitrates,and phosphates and you need to test both tank and tap water to see what you've got and what your tap is giving you. Once you know what you're getting, you can then decide what you need to add to maintain plants which will reduce algae.
I didn't see anything about filtration in your tank specs. What are you using?
As previously stated, you want to balance your tank's nutrient level. I don't know of ANY 'all purpose/all in one' fertilizer that can tailor it's ingredients to the special needs of an individual tank. Your issues come from a lot of light(3watts/gal.). If you had 1.5 or 2.0 you might be able to get by with an all in one fertilizer. It is my opinion that with that much light, you can't.
If you look at the sticky at the top of the plant page on nutrients you will see posts which tell how to obtain the needed individual nutrients locally and cheaply.
Very simple....N, P, K and Traces. Clean water. CO2.
Then you can throw out the 'drugstore' stuff and grow plants naturally.
You're probably sick of testing and posting, but we can't give advice on dosing without knowing what you've got. So one more time....
test and post your latest nitrate and phosphate levels both tank and tap. pH and kH as well. That will tell us how well your CO2 is working for you.

Len

Main thing is that "Total nitrogen" issue.
This means NH4 and uera, not just NO3 which is all anyone should be adding from a fert.

We all add some NH4 via fish waste and that's what should supply that source of nitrogen only.

I can make some very cheap fertilizer if I use NH4/Urea based forms along with NO3.

That's all most nurseries and ag places sell.

Aquariums need NO3 only.

The pond folks often don't make or realize this distinction and suggest the NH4/Urea forms.

Regards,
Tom Barr