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Question about nitrates and fertilizer

638 Views 6 Replies 5 Participants Last post by  tbar23
I added plants to my 29 gallon aquarium about three months ago. This is a BioCube 29.

Tank Details:
36W 10000K 36W bulb - run about 8hrs/day (it also has an actinic bulb, but I don't use it)
264gph pump

Fish stock:
2 Sunburst platys
2 bristlenose plecos
3 cardinal tetras
2 danios (glo-variety)
2 guppies

When I added plants back in January (Limnophila Aromatica, Myriophyllum Mattogrossense, Ludwigia Repens, Ludwigia "Red" hybrid, Alternanthera Reineckii 'Rosaefolia', Hemianthus Glomeratus (baby tear)) I started weekly dosing with:
~1/4 tsp KNO3
~1/32 tsp KH2PO4
~1/4 tsp Seachem Eqiulibrium
and recently, I have added ~1/2 capful (2.5mL, I think) of Fluorish liquid (brown stuff - I think it is the comprehensive).

About two weeks ago, I tested these levels:
API test kit: 0-0.25ppm ammonia, 0 nitrite, 40-80ppm nitrate

Repeat with API test strip: 30GH, 40KH, 6.5-7 pH, 0 nitrite, 20-40ppm nitrate
Last night, I tested these levels:
API test kit: 0-0.25ppm ammonia, 0 nitrite, 40ppm nitrate.

I have read several different things about nitrate levels. Some folks on these forums claim that the tank should be in the 10 - 20ppm range, while others state that 40 is fine and even 80 is no big deal. How does one sort out this nearly 10 to 1 range of "okay" levels?
Recently I have dialed back my KNO3 dosing, but I am thinking about stopping it altogether. Thoughts?
Micro ferts - I have both Seachem Eq and Fluorish. They are clearly different. My water hardness is a little low (30 - 40 ppm which I think is about 1.7 - 2.2 dH). Any advice on dosing of the micro ferts?
Front and side tank pics attached.

The Hygrophila Corymbosa 'angustifolia' looks pretty good.
Limnophila Aromatica looks so-so.
Myriophyllum Mattogrossense looks great.
Ludwigia Repens started off okay, but looks so-so now.
Ludwigia "Red" hybrid started off okay, but looks so-so now.
Alternanthera Reineckii 'Rosaefolia' looks so-so.
Baby tear (HG) looks good.
Anubias looks good.

Found black hair algae (I think) on Marsilea quadrifolia and moved it to another tank (a shrimp tank). However, I also saw a bit of black hair algae on the Hygrophila Corymbosa 'angustifolia'. I tried to cut off the affected areas.
At this point, I am primarily interested in some guidance on the nitrate levels and the micro ferts, but I welcome any inputs.


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Actually you don't have enough plants in there to justify that much ferts.
A weekly 50% water change will equal that out however.
Not that it's 100% but I like to keep my tank(s) where I can see everything or might
I say everywhere in it...lower level of plants than those Dutch style tanks much the
same as your level...where I can look through them.
Since you said tsps I will conclude you have a set of smaller than 1/4 measuring
spoons. You might substitute K2SO4 for half of the KNO3. This will bring down the nitrates. Just to what extent. But I'd say the excess nitrares tells me theplants are not
using up what you are adding(based on my first comment about low level of them)
and I'd try cuttin them to half what you are using total.
Day one just after WC
1/16 tsp KNO3
1/16 tsp K2SO4
1/32 tsp KH2PO4
1/16 tsp MGSO4
Next day
2ml Flourish (get pipettes from e-bay for this, cheap)
3ml Tetra Pride
repete three days later only these two
Try this for 30 days and see how the nitrates are after two weeks and after the 30 days see if any negative symptoms happen/w the plants that make you think their lacking anything.
P.S. Those moss balls have been known to cause problems and I don't remember which problems.
You have a fairly high amount of light and some Excel might do the tank some good/w that light amount.
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With the low GH of the tap water I would keep on using the Equilibrium, not Epsom salt. Just do this when you do a water change, though. Set the GH at the optimum level for your fish. Then test at the end of the week, right before a water change. If the GH has dropped a lot then you might dose a bit during the week, but I have not found that plants use that much.

Fish list is a little awkward. This is a 'Noah's Ark' tank: Two of this... two of that...
2 Sunburst platys-social, prefer groups, but not actually schooling. Males tend to chase females, and the females can die of the stress. Better at least 2-3 females: 1 male. Or all one sex. Hard to moderate water is better, but they are adaptable. Thrive in cooler tanks.
2 bristlenose plecos- Get too big for this tank. Otocinclus are OK in tanks this size, and there are other (small) pleco relatives. BN males can get territorial.
3 cardinal tetras- Schooling fish. Get a dozen. Soft water fish that can die if there is too much calcium in the water. Keep the GH under 3 degrees. Thrive in warmer tanks.
2 danios (glo-variety)- Schooling fish that have a tendency to harass and nip other fish if they are not kept in large enough groups. Get more. Moderate to soft water, mid range temperature.
2 guppies- Social fish that are like Platies: The males can harass the females to death. Hard water to moderate water.
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I agree with Raymond, your running lights & ferts but no CO2 so you haven't got a balance and therefore your plants must be slow on the uptake of the nitrate. Try Excel but add it slowly to acclimatize your plants as it can melt some species. Alternatively you could try adding CO2 or cut down on the ferts and lights.
Thanks for all of the responses. I'll read through the link tonight. Looks useful.
A few follow-on questions:
To ease dosing - how many of these things can be premixed into small batches of solution?
What does the Tetra Pride do? I haven't heard of that one.
To cut down on lights - are you guys suggesting reduced wattage or just less time?
Does it make sense to get a phosphate test kit?

Diana - Regarding the list, I understand your concerns. Until recently, I had two female platys and one male. The older female (mom of the other female) died. Similarly, I used to have four cardinal tetras (one died). I wanted more, but didn't think the tank could handle it. Likewise, I had more danios, but slowly lost a few of them. Guppies - just put six or seven fry in the shrimp tank and plan to reintroduce a few females as they get older. Plecos - my understanding was that the BN plecos only got to ~4". I plan to move one of them to my shrimp tank.

Thanks again!
the nitrates in my tank(s) run between 40-60ppm, I'm now at the point where I only dose csm+b, fe, k2so4 with kh2po4 being done on occasion. I no longer have a need for kno3 as my fish food and fish poop provide me enough nitrate. My tap water has about 15-20ppm in it, so I've just given up trying to keep the nitrates below 20ppm. They have been running at 40-60ppm for about 6 months now. I've seen zero issues thus far.
Just to add a bit more info - I measured KH and GH two days after WC / dosing: 5d (90 ppm) GH and 2d (36 ppm) KH.

I think this makes sense as Seachem EQ raises GH but not KH, right? Necessary to raise KH?
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