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15 Posts
Discussion Starter · #1 ·
I'm new to the high tech tank and this forum. I have in place a 100 gallon corner tank with a GLA regulator with an inline diffuser, Eco complete substrate and 2 160 kessel lights and freshwater orbit strip.
Right now I'm using Seachem liquid dosing. Flourish, iron and potassium with root tabs. I would like to switch over to dry ferts. There's so much product!! I'm totally confused as to what I need to use. I've read Tom Barr report and read and Watched everything out there. Any input as to what direction to go would be wonderful!!!
Thanks so... Theresa

11,721 Posts
Plants need about a dozen elements to live. They use different elements in different amounts.
The elements they use the most of are hydrogen (H), oxygen (O) and carbon (C)
Some are already in the tank (hydrogen, oxygen).
You are adding carbon in the form of carbon dioxide.

The elements they use the next most are referred to as macros.
Nitrogen (N), phosphorus (P) and potassium (K).
Fish food can supply reasonable amounts of N and P for a low tech tank, but is somewhat low in potassium. None are in enough supply for a high tech tank (high light, CO2)

The elements the plants use in a mid-range amount are secondary.
Calcium (Ca), magnesium (Mg), sulfur (S)
If the water has a GH of at least 3 German degrees of hardness, then it is likely the Ca and Mg are present in enough quantity for soft water fish and many plants. The plants use Ca and Mg in a ratio of about 4 parts Ca: 1 part Mg. The water does not have to have this exact ratio, but sometimes the ratio is really off and you need to dose one or the other. If you are keeping hard water fish then the GH will be a lot higher and the plants should have no problems, as long as the Ca and Mg are both there.
I have not heard about any deficiencies in sulfur in planted tanks. It is added to the tank in a couple of forms (dechlor is one).

Plants use a lot of minerals in very small amounts. These are referred to as micros.
Iron (Fe) is usually dosed often because it tends to get locked up in the substrate in a way plants cannot get it. Use chelated iron to make it last longer.
All the other micros should be dosed in small amounts. Plants need them, but there are several sources in the system. I would not double up on these sources (such as root tabs and liquid dosing).


Here is what I would do:
1) Read the label on the root tabs. What is in them? How long do they last? Can you test the water for anything on that list?
If a water test shows the root tabs are still supplying nutrients then do not add more, yet. Good to get ready, though.

2) What is the NO3 test? Is this just from fish food? Or is some of it from the root tabs? (no, I do not know how to tell where the NO3 is from)
If the NO3 is from fish food, then dosing K and Fe is just right. The fish food is supplying N, P and most traces.
If the NO3 is very low (no matter if it is from fish food or the last remnant of the root tabs), then start dosing all the fertilizers.

3) When you have pretty much used up the liquid ferts, then have the dry products on hand and be ready to mix them into liquids. (The bottles from the liquid ferts are good for this).


To mix the fertilizers, according to the EI method:
Figure out how much you will want to dose the tank with for 1 week. (read the recipe, do the math)
Put that much of each product into 2 bottles:
KNO3 , KH2PO4 and K2SO4 (if you want to use it, see my notes below) in one bottle.
CSM+B and chelated iron in another bottle.
Put any amount of water in each bottle that is divisible by 3. Make sure the ferts will dissolve- I would suggest not less than 99 ml, but you could use 3/4 cup, or any other amount that works for the tools you have. Lets say you put 99 ml in there)

Dose (shake well to be sure it has all dissolved each time):
33 ml of macros Monday, Wednesday and Friday.
33 ml of micros Tuesday, Thursday and Saturday.
Sunday is 50% water change.
You can test the water on Sunday right before the water change. Did anything (that you have a test for) go way too high? You can adjust the mix for next week.

OK, here is the note about K2SO4:
If you have a lot of fish in the tank you are probably adding a lot of fish food.
Fish food is high in N, P, and most traces. If the NO3 from fish food is fairly high, then you can assume the fish food is also supplying enough P and most traces.
Adjust the dosing to account for this by reducing the amounts of KNO3, KH2PO4 and CSM+B.
But fish food is low on K and Fe. To give the plants enough potassium without over dosing the NO3 use K2SO4 instead of some of the KNO3.

Some people are finding that the plants may show some toxicity if too much trace mineral blend is used. The votes are still out on this. Just in case:
If you want to dose less CSM+B that is OK, but add a little bit of chelated iron. Plants do need the iron, and there are not a lot of other sources for this element that plants can use.

15 Posts
Discussion Starter · #3 ·
Diana... Planted Tank Guru that you are!!! Thank you!!! Your answer is so spot on. It really clariyied all the muddle in my head with all the information coming in. My tank has been planted for 2 weeks. Nothing has died or melted. Some things are doing better than others and everything looks great. I did have a low teck planted tank 5 years ago that did really well plants actually flowered. I dosed with Seachem. This time I decided to get serious. I cannot thank you enough for your reply. Do you mind if I ask you questions with regards to the fertilizers in the future. Again thank Diana 🍀

200 Posts
I add to the praise: Your summaries are always a good read, Diana.

A side note: The average soil substrate contains about 40 grams of iron per 1 kilogram, which should be more than enough for many decades, and even though the iron is not readily available there, the rooted plants should be able to get it from it. So in case someone uses soil substrate in his/her tank the iron (as well as micros) supply won't be probably needed.
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