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Having trouble with one planted tank, help.

2K views 5 replies 3 participants last post by  WisFish 
#1 ·
I am having trouble with a planted tank, it a 37 gallon setup and planted last December. This is my one non CO2 injected tank, and maybe the problem is my tendency to treat it like the CO2 injected tanks in terms of fertilization. The plants are slowly growing smaller and I have to scrape the glass every week so I can see my 4 angelfish and one yoyo loach. I have been trying to wait the problem out thinking things would eventually stabilize and get going. I recently moved several dwindling plants to another tank and they are already greener and are shooting up new leaves. I noticed when I removed the plants that the roots hadn’t grown much if at all since I planted them. My target nitrate level has been 10-20ppm which I dose to with potassium nitrate after every water change (weekly 25%) ¼ teaspoon is typical, and I usually add potassium in the form of potassium sulfate also ¼ teaspoon. I add PMDD several times a week but sometimes mix things up a bit with some Sea-Chem Flourish. The tap water is rather hard 9-10 dKh is typical and it is high in calcium thanks to the geology here. Substrate is eco-complete layered under medium gravel. The light is a 65 watt power compact 6500k bulb, 8 hours a day. Plants vary, there are cryptocoryne, echinodiorus, vallisneria, nymphaea, ludwigia, microsorium, and aponogeton varieties. I think I have every need covered, so I’m not sure what the issue is. For lack of any better ideas I think I am going to try to reduce the macro-ferts down below 10ppm and see if that helps control the algae. I would appreciate any suggestions on ways to control the algae or getting the plants to grow.
 
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#2 ·
I think you've answered your own question in your second sentence. In a word, the balance is out, which is why the plants are not doing well and the algae is out of control. With all the light and nutrients, CO2 in this tank would probably restore the balance, but at the same time reducing the light and nutrients would also restore it and the plants would improve and the algae would (once cleaned up) be normal.

Assuming you want this tank to improve without going to CO2, I would immediately cut back on the fertilization. Do the weekly partial water change (remove as much algae as you can) but don't use liquid fertilizer. I would want to reduce the light down to 1w per gallon, but that isn't possible with just one tube, and I wouldn't want to cut back much on the duration as less than 8 hours isn't much for tropical plants. You've got more nutrients in the substrate, but that probably won't be much of an issue so I'd leave that alone. Trim the plants, and see how they respond.

The fact that they improve when you move them into the other tanks with CO2 supports my thinking; the balance needs to be restored so the light and nutrients are complementing each other, which at present they are not. It is certainly possible to have a thickly planted tank without CO2, provided the light and nutrients are balanced. You can see this in the photos of my two aquaria, which have regular aquarium gravel (no additives), 1w full spectrum light per gallon, no CO2, and Seachem Flourish twice a week. Good luck.
 
#3 ·
Actually I could put the old 40 watt fixture back in, but between 40 and 65 watts I don’t see it making too much of a difference and would rather have the higher of the two. Or at least would like to have several concurring opinions before I swap out the fixture. Also the tank is 21” deep, something to consider. CO2 has been the keystone of my other tanks, I am sure without it they wouldn’t be doing so well. Part of the plan for this tank was to do it without CO2 mainly because it is cost prohibitive and doesn’t support the main focus of the tank which is the angels, but also because it presents a new challenge. I will reduce the macro nutrients and see what happens, I will try just flourish regimen, but will probably end up going with the Plantex CSM+B (PMDD) which is just micro nutrients if I get the same results because it is more cost effective.
 
#4 ·
My target nitrate level has been 10-20ppm which I dose to with potassium nitrate after every water change (weekly 25%) ¼ teaspoon is typical, and I usually add potassium in the form of potassium sulfate also ¼ teaspoon. I add PMDD several times a week but sometimes mix things up a bit with some Sea-Chem Flourish.
I'm not an expert but I haven't heard of anyone actually adding something to bring the nitrates up. The fish waste naturally will supply nitrates. I'd try discontinueing the potassium nitrate. Without CO2 I'd only add ferts once a week. I'd keep the lights 65 watt lights. Good Luck.
 
#5 ·
My target nitrate level has been 10-20ppm which I dose to with potassium nitrate after every water change (weekly 25%) ¼ teaspoon is typical, and I usually add potassium in the form of potassium sulfate also ¼ teaspoon. I add PMDD several times a week but sometimes mix things up a bit with some Sea-Chem Flourish.
To calarify by PMDD I mean Plantex CSM+B solution, it is just trace minerals in very low concentration and there is no N-P-K. I add it 2-3 times a week. I had been adding nitrate and potassium once a week with water changes.
 
#6 ·
Everyting I've ever read states that an excess of algae is usually due to more nutrients in the water than what the plants can use. Reducing those nutrients should reduce the algae. In my case, to slow down the algae growth I had to add more plants. I'd try stopping the potassium and only add the PMDD once a week.

If the plants came from a tank that had CO2, the plants could grow smaller due to the change in conditions.
 
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