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Need Help!! Phosphate off the Scale!!

2K views 5 replies 3 participants last post by  Wasserpest 
#1 ·
Hi...
I just picked up a new Hagen Nitrate and Phosphate test kit for my
29gal. I just re-started my tank with fresh gravel and new plants and
lights. I have 95watts, and DIY C02. I also completed a 50% water
change yesterday, and another 25% waterchange today, because of a
small thread/ hair algae outbreak. So I wanted to make sure my water
was clean before testing. The tank has been running for 6 weeks,
cycled and has a good bacteria load going for sure. Maintenance is
kept up religiously. Plants were growing for a couple of weeks, but
are showing signs of slowing down, and yellowing.

Readings are as follows: (after water change)
Ammonia: 0ppm
Nitrate: 0-5ppm
Phosphate: 5ppm+
K:??
Nitrite: 0ppm
PH: 7.0
GH: 8deg
Kh: 9deg
c02: ~20ppm
temp:78
Fish load minimal: (4 Cardinals, Pleco, and a Cory)


Problem here is obviously the Phosphate!! I tested my tap water and it
came back zero. Then I did a test in the tank (after the water
change), and it was off the scale?!! I dont get it! Something is
really leaking Phosphate into my tank...and I dont know what? I have
fertilizer spikes under the plants which have Phosphate in them, but
they are way under the gravel and are never disturbed.

Someone told me that Activated Carbon in your filter releases
Phosphate, but I found that hard to believe as Activated Carbon is
supposed to suck up nutrients rather than release them right???

I'm really stuck on this one! Can anyone give a list of possible
sources of Phosphate, that I might not be considering. At present, I
am not dosing any ferts, and havent since start up. The phosphate just
magically appears for no reason!

Thx in advance,
Nick.
 
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#2 ·
First thing get rid of the carbon. It will remove nutrients form your water and make them unavailable to your plants. Second, thats a lot of po4 are you sure you are testing correctly? If the levels are that high just do a series of water changes. You should be on the right track afterwards, just maintain your no3 and po4 at a 10:1 ratio, your plants are probably starving for no3 as seen by the yellowing.
 
#3 ·
Hi Nick, welcome to the Planted Tank!

I agree that carbon isn't needed in a tank. Water changes are much better, and it looks like you are doing those. Replace the carbon by an inert medium of your choice, like sponges or ceramic rings or lava rock, anything with a large surface.

Next thing I would suspect are the fertilizer sticks... maybe the Cory thinks those are delicious and digs them up at night? Not sure... I use them too and still have to add PO4.

I suppose you don't use any pH buffers? Some of them are phosphate based.

What are you using as substrate?

What are you feeding? How often? Is there a lot of leftovers?
 
#4 ·
Hey..
Ok..I'll loose the Carbon in the filter. My gravel is just plain rock gravel, nothing special. Feeding is only 2-3x week, and just a pinch too, because there is hardly any fish in there right now! I am really stumped on this one. Everyone told me to use root tabs, and then when I do everything goes haywire! The root tabs are those Nutrafin Plant-Gro from Hagen I think. They are not the Jobes ones. They even say low phosphates on the package so I'm not sure why they are not balanced?? Why are the plants using the nitrogen but not the phosphate? I dont get it!!

Nick
 
#5 ·
Hey...
So last night, I did a another 50% water change. Filled the tank again, and did another 50% to dilute the phosphate again. It kinda half worked. The readings came down to around 2.5ppm from over 5ppm. I also took all the carbon out of my Penguin filter insert, and took all those damn Nutrafin spikes out. I looked at the box again and the reading were 16-9-12 (NPK). That doesnt seem like a 10:1 ratio to me! And on the back there was two different sources of phosphate.

I also cut the lights back by 60% (turned off the power compact), until I can get my ratios right. I hope that doesnt kill my plants. I added some N as the readings were zero after those huge water changes. Readings were at 5ppm this morning, added a bit more before leaving for work. When I can get them up to 10 or more I'll turn the light back on.

I think I need more fish too. My plants are eating my Nitrates faster than my fish can produce them. With 95watts over 29gallons, I will need some heavy fert dosing. I rather just have more fish to help out with!

Keep you posted on the progress
Nick D
 
#6 ·
Although for the planted tank enthusiast, fish are just fertilizer, I would not use them as my only nitrate source. Adding NO3 via KNO3 is much easier to control, and probably healthier for those poor fooshies too.

Now that you took out the spikes, you might need to do a few more water changes to get the PO4 levels down to normal. Without the carbon, your plants will probably be happier, and help more in reducing the phosphates.

Hope everything will be balanced soon...
 
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