Your advice about fertilizers

[Lukara]

Hi, I’d like to aquascape and put some quarantined fish in my 50 gallon tank, but before I begin, I would like to ask for some advice about fertilizers.

My plans for the tank are:

-Plants: Anubias, Java Fern, Java moss (mostly plants that attach to rocks and wood) and maybe some crypts
-Lighting: Either 2x40 watts or 3x40 watts (regular fluorescent tubes)
-Pressurized CO2
-Fish: 12 red tail rasboras and 3 angelfish

My water parameters (after sitting in a bucket for 24 hours) are:

-KH: 1.7
-GH: 2.2
-PH: 7.6

I’d like to know what kind of fertilizer schedule I should maintain for the kinds of plants I’m planning on using and what I should do about the low GH and KH of my tap water. Can anyone please give me some advice on this?

 

[djlen]

How heavily are you going to plant this tank? For instance, will 50% of the bottom be covered.....75%? Or do you anticipate just a few plant?
The plants you mention are not especially nutrient hogs, but with CO2, they will definitely need supplementation from you.
You might be able to get away with SeaChem's line of liquids if it's going to be a lightly planted tank.
So give us an idea of what your plant load will be.

Len

 

[Lukara]

I have 2 big (both are approx. half the tank in length each) and 2 medium/smaller pieces of driftwood in the tank which I plan to attach most of the anubias and ferns to. Whatever coverage the bottom of the tank will have will be with java moss attached to rocks and maybe a few anubias attached to rocks as well, so about 40% ground coverage. So overall I'd say the tank will be for sure a moderately loaded planted tank.

 

[djlen]

You can start dosing lightly. You can get N,K and P from the SeaChem Flourish line as well as the Traces you'll need from plain Flourish. Don't get Flourish 'Trace'. Plain Flourish is more complete. I would dose them at 1/2 strength per instructions on the bottle to start with and see how the plants respond and check your N and P for content.
Even though it's a fairly large tank, with just a few plants I would tend to err on the side of caution and if they need more, they'll let you know.
At 2X40 watts they probably won't....3X40, maybe they will.
If you'd prefer to use the generic versions check the sticky at the top of the page and get back to us for recommendations on dosing.
I would raise that kH to at least 3 - 3.5 when using pressurized CO2.
You can do this by putting a half cup or so of crushed coral into a nylon bag and putting it into the filter. If it's used coral from the LFS you can decontaminate it in the oven by spreading it on a cookie sheet and baking for 15 mins. Then rinse and you're good to go.
Be patient with the coral because it's slow acting.
Until your kH does come up go easy with the CO2.

Len

 

[Lukara]

Thanks for your advice Now I have some more questions

Okay, I decided to go with 3x40 watts.

I will buy Flourish for my traces. As for NPK, I have KNO3 (Salt Petre), Fleet, and K2SO4. Should I aim to keep nitrates at 5-10 ppm, phosphates at between .5 - 1.0ppm, and potassium at 20ppm with my kind of setup? Should I even use any K2SO4?

Do you have recommendations on what levels of CO2 I should aim for?

I'm thinking of using baking soda to raise my KH because I prefer the immediate effect.

As for my GH which is 2.2, do you think I should do anything about this? Or will Flourish be enough to compensate calcium and magnesium?

 

[djlen]

I wouldn't worry too much about the gH. You can dose Mg(Epsom salts) which will help.

Baking soda is quicker, but doesn't last as long. Maybe a combination of both and eventually the right amount of coral will hold it wherever you want it.

Until you get your kH up, I would keep your CO2 around 15ppm. Once you start seeing 3.0 - 3.5kH, go for 25ppm. This will be easy to hold once the kH is right, and with a good needle valve you won't have to worry about fluctuations.
Always make frequent checks of pH for CO2 content until satisfied that there is no drift over time.

Your N, P, numbers are right on. Shoot for those consistently.
Flourish is a good Trace mix.
Consult Chuck's calculator for dosing K. It will tell you how much K+ to dose for 20ppm. However, Tom Barr's latest theory is that with a light fish load, extra K may not be necessary and that fits with your fish load.
I dose the difference between what KNO3 gives and the 20ppm with K2SO4. I figure, I've got it. Why not use it.
I guess that's a shot you'll have to call.....................

Len

 

[Lukara]

I will give your advice a shot once I have all the plants purchased and in place and I'll let you know after a few months how things are going. Thank you again for your help