[TheGiantDwarfShrimp]

Everything I read about fertilizers says something along the lines of "this only applies to high tech plants with high light and CO2" and that it would be a waste to dose in low tech tanks. My tank is a 90 gallon community tank with 4 32w T8 lights with a dirt substrate. All of my plants have been growing great up until recently. I think the problem was a mix of my light bulbs going bad and the dirt is running out of nutrients. My nitrates have been 0 for a few months but I am not exactly sure when that happened. I believe the lack of nitrates is what caused a BGA outbreak in the tank.

Is it true that without CO2, fertilizers are pointless? I consider the tank to be in the middle between high and low light. It seems to be just enough light not to cause too much algae and still grow plants well. Downoi was even doing great until the lights went bad. Then they started growing tall and thin.

For a tank like this what kind of dosing regiment should I follow? Should I just dose enough KNO3 to keep nitrates above 0?

 

[Tzac]

Dosing with the EI method is so cheap when using dry ferts that I feel like it is worth it to use them even without CO2. I have read that it will also prolong the life of your dirt greatly. In my dirt tank I use EI and Excel under Med light with good success.

 

[JeffHerr]

My nitrates have been 0 for a few months but I am not exactly sure when that happened. I believe the lack of nitrates is what caused a BGA outbreak in the tank.

Likely... Or, at least it didn't help at all...

Is it true that without CO2, fertilizers are pointless?

Absolutely not! Though it may be true that without supplementing carbon in some way (like Excel/Glut), it becomes much less important (water changes may even give you all you need...)

Get your Nitrates up to 10 - 20, best done by following EI or some comprehensive approach (don't just dose Nitrates...)
And listen to Tzac; use dry ferts. Small initial purchase cost and you'll use them forever...

 

[roadmaster]

I dose EI daily amount for high tech,my size tank, once a week in low tech non CO2.
No need to dose for high tech,daily for the uptake by plant's just isn't the same in low tech, lower light,non CO2.

 

[TheGiantDwarfShrimp]

I added some KNO3 four days ago and have collected water sample from each day. I am going to test them all at the same time to make it easier, but hopefully that will give me an idea of how quickly the plants use up nitrates. I already have some dry ferts but I will need to buy more because I was only using them for a 20 gallon shrimp tank.

Once I figure out how much KNO3 I need to dose daily/ weekly should I use that to determine how much of the other ferts I need to dose? Should I just use the regimes posted in the sticky and adjust it to the amount of KNO3 I use, or are there better directions to follow for low tech tanks?
http://www.plantedtank.net/forums/showthread.php?t=21944

roadmaster, are you saying there is no need to dose daily on a low tech tank? I am OK with dosing 2-3 times per week but if it is not necessary once a week would be a lot easier.

 

[roadmaster]

I added some KNO3 four days ago and have collected water sample from each day. I am going to test them all at the same time to make it easier, but hopefully that will give me an idea of how quickly the plants use up nitrates. I already have some dry ferts but I will need to buy more because I was only using them for a 20 gallon shrimp tank.

Once I figure out how much KNO3 I need to dose daily/ weekly should I use that to determine how much of the other ferts I need to dose? Should I just use the regimes posted in the sticky and adjust it to the amount of KNO3 I use, or are there better directions to follow for low tech tanks?
http://www.plantedtank.net/forums/showthread.php?t=21944

roadmaster, are you saying there is no need to dose daily on a low tech tank? I am OK with dosing 2-3 times per week but if it is not necessary once a week would be a lot easier.

I dose once a week,with what most folk's who run CO2 injection dose every other day or more.
I googled... "Estimative Index dosing" for (your/my size tank),and found daily amount suggested ,,and just decided to try this much of everything once a week or every two week's.
Plant's responded favorably.
I perform weekly water change as I have for decades.

 

[Raymond S.]

I hope it comes out where IO left it.
http://calc.petalphile.com/
If not, on the Fert section the third line of the first thread gets you a calculator(which proved to me that I'm
not a rocket scientist/takes some patience to figure for me) and if you start it off with your tank size/diy/gimmie
you will get a drop down page and the second drop list has "EI low light/weekly" (you can add later if/when
you see that it can use more). With 4x T8 you CAN have on the med or low end of the med level.
I have a shorter tank(12" from light to sub) and the Zoo Med Ultra(6700K) and the Zoo Med Flora(5000K)
together produce a lot of algae. So I need to use the Tropical sun(5500K) plus a Flora to stop this.
But on your tall tank I might substitute a 10,000K for the Ultra bulbs to off set the low visible light which
the Flora has.
I use a weekly dose of what the EI low light/weekly category says but with a substitute for one ingredient.
I should not expect to see any faster growth in my plants without all three Higher lights/ferts/CO2.
But I do see more healthy plants without symptoms of any lacking in nutrients and it's been too long since
not using these ferts to say there is no faster growth, but it's not usual.
BTW: I found a conversion on the internet but it's confusing because mg is weight and teaspoon is volume.
So it depends on what density the material you are weighing. But generally 1000mg or 1G = .48 teaspoon.

 

[MarkM]

I looked at EI and PPS and elected to use PPS. This is similar to EI but simpler I think. PPS is designed for a high tech tank and includes dosing once a day. I mixed according to the plan but does once a week or ten days in my low tech tanks. The initial purchase of dry ingredients was not expensive and I bought a cheap electronic scale and two mixing bottles. Still have more than half of the original ingredients after two years. Seems to work.

 

[Zorfox]

Everything I read about fertilizers says something along the lines of "this only applies to high tech plants with high light and CO2" and that it would be a waste to dose in low tech tanks

Not true. The dosage, water changes and frequency of both are higher in high tech tanks but low tech requires nutrients as well.

Plants need nutrients regardless of where they grow. High, medium or low tech.

It's the same for people. Very active people such as athletes require more calories than couch potatoes. However, we all need to eat.

Nutrients come from many sources such as organic substrates, organic waste and food we feed our fish. Many low tech tanks rely on these for a nutrient source. The lighting is generally low which reduces the plant's uptake. This slows things down enough that we may not need to dose additional nutrients. When nutrients are utilized faster than they are provided plants suffer. They all need to "eat".

Plants use three things far more than others, commonly referred to as macro nutrients;Nitrogen, phosphorus and potassium. Those are like protein and carbohydrates for humans. We may be able to get by for a long time without enough zinc but stop eating proteins and carbs...

So do YOU need to dose nutrients?

You've noticed a decline in plant growth which is a big clue. You also have 0 nitrates. Nitrates are the primary source of nitrogen for plants. These two things alone say yes you need to dose something.

Here is a good article on non CO2 methods at the Barrreport.