# Fertilization questions (I think)



## eraserbones (Jul 18, 2006)

I've almost certainly bitten off more than I can chew, here, but I'm looking for advice anyway. My setup:

90-gallon tank (48" x 18" x 24" high)
pH-regulated C02 injection (2.5 kh and ph of ~6.5)
2x175-watt 6500k metal halide lights + 2x40 watt flourescent tubes

Many of my plants are growing well (in particular several lillies, mosses and ambulia) but I have a couple of problem areas. Here are some photos:









R. rotundifolia is a bit twisted and tends to grow horizontally









A. Nana with yellow, mottled leaves. Perhaps this is normal and I should just prune out the old ones?









True evidence of my hubris: R. Macrandra. It doesn't really look the right color to me. Also, growth is very slow, and the leaves have holes and are slightly withered.

Also, not pictured, are several stems of giant hygro. They look OK, but grow very slowly -- less than an inch per week.

Do those three problems spell out any single, specific nutrient deficiency? Or is my problem lack of fertilizer in general? Because the tank contains numerous fragile shrimp (snowballs and red bees) I'm very conservative about fertilizing. I add 'leaf zone' according to the label, which seems to keep my K and Fe levels within reason. I also add a tiny, tiny bit of Nitrogen fertilizer, equivalent to about 1ppm twice per week. Nitrogen seems like an obvious culprit here, except, isn't macrandra supposed to like low-nitrogen levels anyway?

Any thoughts or advice are welcome. Thanks!


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## trenac (Jul 16, 2004)

With the amount of light you have along with the addition of C02 you need to be dosing a lot more ferts than you are now. So it is safe to say you have a nutrient deficiency. Here is a site to help ID the deficiency(s) you have... Nutrient Deficiency in a Planted Tank

I personally would think about reducing the amount of wattage you have down to 3-3.5 wpg. This will help in reducing the amount of ferts you have to use with the shrimp.


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## hoppycalif (Apr 7, 2005)

With that much light you really need to be sure you have as much CO2 being injected as the fish can tolerate. And, you need to dose adequate fertilizers, which will essentially vanish within a day of dosing, as the plants use it up. So, unless you go far too high with the CO2, and just helter skelter dump fertilizers in the tank, the shrimp shouldn't be bothered at all. Check out the EI fertilizing method for a simple way to handle this.


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## John N. (Dec 11, 2005)

Best bet if you don't want to fertilize your tank heavily is to reduce the lighting and thereby reducing the plant's metabolism and need for fertilizers.

I believe you have a potassium deficiency though. I would purchase some Aquarium Plants, Aquatic Plants, Planted Aquariums, and Aquarium Plant Fertilizer fertilizers, and dose sparely on the all fertilizers via the EI method (2x a week instead of 3x).

Oh, I believe that red plant is A.reineckii and not R.macrandra.

-John N.


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## eraserbones (Jul 18, 2006)

*Thanks!*

Thanks, everyone, for your suggestions. If I switch the flourescent tubes so that they're on for a few hours before and after the halides, but not at the same time -- that would get me in the neighborhood of 3.5 wpg, correct?

Should I reduce the photoperiod as well? (I have the halides on for 9-10 hours right now.)

I have one other question about fertilization -- are there any test kits that can detect the low levels of nutrients that I'm after? My nitrate test barely registers below 10ppm, and 10ppm is already higher than I want things.

> Oh, I believe that red plant is A.reineckii and not R.macrandra.

That makes perfect sense! I ordered both plants at once, and one bag of plants disintegrated in shipment... I wasn't sure which one survived. Too bad I just bought more Reineckii today, though


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## John N. (Dec 11, 2005)

Switching the flourescent tubes off will probably put you around that 3.0-3.5 wpg area. 

If you can't shut off one of the halides, the next thing to do would be reducing the photo period to say 8 hours. 

I believe some pricey LaMotte test kits can detect low nitrate levels. But basically if you dose sparely your shrimp will likely be fine. Many people have Cherry Reds and dose plantex and other gregwatson ferts, and the seachem flourish line without issue. I imagine the snowballs shrimp will fair evenly as well as the Red Cherry Shrimp.

I know your concerned about fertilizing with shrimp, but you'll need some fertilization for those certain plants that are having those problems. Even the lower light, slow growing plants need some ferts. Anubias shoots yellow leaves when it's having a potassium problem in my experience. A.reineckii could benefit from some trace elements, and the NPKs.

R. rotundifolia grows horizontal normally when near the surface. 

If you're not keen on fertilizing I would suggest not growing the plants that seem to need the ferts the most, that is if the reducing the photo period doesn't help any thing.

-John N.


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## Laith (Sep 4, 2004)

I agree with the others; you're running into macro deficiencies.

As an example, on a well planted tank with 2.8wpg and CO2, I usually add around 12-15mg/l of NO3 and 1.5mg/l of PO4 both 3x a week with 50% weekly water changes. If I add less than that, I start to see problems.

The last time I tested for NO3 (with a calibrated test kit, about six months ago) my NO3 levels were around 20-25mg/l.

I've never seen any problems with fish/shrimp using this amount of dosing. And on this specific tank I have a couple of Discus and lots of Amano shrimp.


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## eraserbones (Jul 18, 2006)

*Nitrates vs. shrimp*

It's good to know that I'm a whole order of magnitude or so below what I need to be adding. But, just a note, for eavesdroppers -- I have Amanos in a different tank, and I find them to be vastly more tolerant of nitrate levels than other dwarf shrimp. I had a massive die-off of cherry shrimp at around 10ppm while the Amanos continued to thrive.

And, I haven't exprimented (and I don't plan on it) but bee shrimp have a reputation for being even more sensitive than cherries. Sounds like light reduction is a good first step for me.


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