Phosphorus, KH, Iron and planting substrate question - The Planted Tank Forum
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post #1 of 3 (permalink) Old 12-25-2014, 07:59 AM Thread Starter
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Phosphorus, KH, Iron and planting substrate question

1. Although Phosphorus is one of the macros for plants, do you still dose it (low dosing) even though it's in fish food, poop etc? Too much causes algae outbreaks right?

2. My tap has 6.4 pH, 0-1 KH. If I want to keep GBRs and cherry shrimp in the not too distant future, I need to get my *pH under 7 and a KH of at least 3* (pH for the Rams, KH for shrimp molting). I've tried crushed coral before but I couldn't control the amount of buffers I put into my tank and my pH always went to 7.6 and screwed everything up. Would seachem's alkaline buffer be better? Would I have to dose it weekly? Any better options?
(Note: I may have confused myself here with the KH. I think plants need a minimum of 3dKH, whereas cherry shrimp need > 3 dGH for molting?)

3. Do I really need Iron ferts, like seachem flourish iron, if I don't grow plants that are red? Iron is found in flourish comprehensive and root tabs too no?

4. I'm planning on getting a better substrate and replacing my old crappy substrate come spring time. I want to know if it's true that eco-complete doesn't have much nutrients but relies on it's CEC index to feed plants? Would you recommend eco-complete? The guy at the store says it lasts 7-10 years.


Last edited by Codzilla; 12-25-2014 at 08:13 AM. Reason: reason for editing?
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post #2 of 3 (permalink) Old 12-25-2014, 11:22 AM
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That is exactly the PH/KH of the water in a pond/stream near my house.
I used some of it when I first set up my tank. Since I got the fish from it they were happy/w it, but I had issues/w plants in there.
Most of the info you have is a bit older than what is current in those beliefs now.The general thinking on algae is that it grows when plants are in poor shape and not growing well or just very few of them. The Phgosphorus is a regular ingredient in fert dosing though much lower in quantity than most other nutrients except for what is called the Micros. That BTW is what Flourish comprehensive is.
The Micros will be the Plantex CSM+B that you see on fert plant package list.
THAT contains iron, though many people do add more in the form of FE @ 10- or 13%.
The liquid ferts are separated by nutrients so that you can add more of only one if
you think it is needed(or so that you will need to buy ten different types to do your job)
and the usual LB of dry nutrients has a LB of what you just spent $8 for a teaspoon full of in that bottle. And that LB of Potassium for example cost $4.
Check/w the local pet shop to see if the fish are in the same water that your tap is. Most chain type stores don't change the PH in the water they use so asking is in order here. Whatever water they are using the fish are used to so you may not need to change that. You may need to add something like Sea Chem Equalibrium for the shrimp.
Raising the KH by adding Baking soda works, but also raises the PH.
That is an aria I'd rather leave to those more experienced/w.
Sometimes you hear people on here say they got more red from their plants by adding iron, but generally it's not thought to work on all plants across the board.
CEC will be 98% of any sub's ability to provide nutrients for plants except for dirt.
Root tabs change that picture and Osmocote+ capsules are complete nutrients.
I know at least one person who just uses Pool filter sand in all of his tanks and no root tabs and he has lots of plants listed as "rooted" type plants like Sword/Crypt.
He uses water ferts only and his tanks look just as good as anyone else's do.
But no doubt the tabs do help rooted plants.
In a tank/w few plant they usually can get the phosphorus they need from flake type fish food. Certain types of plants or lots of plants and you need to add it.
With a "Fish Tank" you only need test the water for water quality mostly in ammonia and nitrates and your good to go. But once you put more than just a few plants in one you open a whole new door of info.

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post #3 of 3 (permalink) Old 12-25-2014, 12:28 PM
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Plants need about a dozen elements to live. Some are pretty abundant, and fish food does supply some. Fish food has most of the nutrients that plants need, but in small amounts. When you get better light and add carbon the fish food is not enough.
The first nutrient deficiencies most people find are potassium and iron. Fish food is also low in calcium. If the GH of your water is over about 3 degrees, then the calcium and magnesium is probably OK. In really soft water (low GH) add Seachem Equilibrium or other GH booster to raise the GH to about 3 degrees. This will supply the Ca and Mg the plants need. Equilibrium also had potassium. This is good, too.
Research the fish to find out what GH they prefer. Plants are just fine with a higher GH. GBR thrive and breed through a wide range of conditions. Their ancestors were soft water fish, which means low GH. Mostly they still are, but if you get them from a breeder who is raising them in harder water then they are more adaptable. GH is more important than KH for the fish.
Once you have the GH right, then I usually make the KH equal to the GH. This sets the pH pretty much in the right range for the fish. Then I would run the water through peat moss to add the organic acids that many fish like. This can fine tune the pH for black water fish.
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