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phosphates in tap water

2975 Views 10 Replies 6 Participants Last post by  rick dale
My tap water has 0.25 ppm phosphate.is this enough to cause problems?
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You may want to add some. That's pretty low. In my low tech tank I aim for between 1 and 1.5 ppm.

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phosphates

My tap water tests 0.25 ppm and my tank tests o ppm
Then add some. Many authors will say low phosphate is one cause of green spot algae. Mine went away when I got phosphate up where it should be. Your tank probably test 0 because your plants are using it up.

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phosphates

I am still new to a planted tank. I read that phosphates cause algae and then they say to add phosphates. I'm confused. Anyone care to explain in depth.
If your not keeping a planted tank, then phosphates can build up and yes, you can have an algae issue.

With a planted tank, phosphates, in moderate amounts, are plant food, and the plants remove it. It's amazing how much a heavily planted tank can consume. This is why we want a certain level of phosphates in a planted tank.

With a planted tank your getting into a more advanced type of system, so some things are going to be done a bit differently compared to a non-planted tank.
Here is where the 'phosphate = algae' idea got started:

In nature there is not a lot of phosphate in the streams, but algae and higher plants do OK.
But many years ago laundry detergents had higher phosphate levels, and the processing of used water did not remove them. The treated water, released into rivers and streams was still high in phosphate. The algae grew like crazy. Then there was a big die off and the decomposing algae took more of the oxygen out of the water and the fish died. Big stench, literally and figuratively.
The scientists traced it to the phosphates, and then there was a big advertising thing about 'low in phosphates' laundry detergent to prevent algae blooms.
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The truth:
Plants (including algae) MUST HAVE phosphorus to live. It is required in such large amounts it is considered one of the macro nutrients along with nitrogen and potassium.
Plants use phosphates in a ratio with the other nutrients that makes it advisable that the aquarium water test about 1 part phosphates to 10 parts nitrogen.
Since many planted tank people keep the NO3 at about 5-20 ppm, this means the phosphates should be around .5-2 ppm.

If you use root tablets then the plants can get their phosphates that way, and the tank water can test as close to zero as our test kits can show.

Since your tests are showing that the plants are removing all the phosphates from the tap water, I think you need to add phosphates to the water or the substrate.
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Here is where the 'phosphate = algae' idea got started:

In nature there is not a lot of phosphate in the streams, but algae and higher plants do OK.
But many years ago laundry detergents had higher phosphate levels, and the processing of used water did not remove them. The treated water, released into rivers and streams was still high in phosphate. The algae grew like crazy. Then there was a big die off and the decomposing algae took more of the oxygen out of the water and the fish died. Big stench, literally and figuratively.
The scientists traced it to the phosphates, and then there was a big advertising thing about 'low in phosphates' laundry detergent to prevent algae blooms.
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I might add a bit to this as well. I was near Table Rock Lake in SW Missouri when phosphate in sewage came up. The end of the lake where the larger city sewage flowed in was becoming a real problem for people along the lakeshore. Boats left in the water would get overgrown just over the winter and then would have to be pulled and scrubbed. During the summer the water got so green in that end of the lake that tourism was being ruined. When water skiing one does not want the water to foam! My brother sold his cabin and we began going to another arm to get clear water.
Once the city began processing the water to remove the phosphate, the water cleared dramatically.
Without phosphates your plants will stop growing and then die. You always want some in the tank at all times. My tap water has 2ppm.
Here is where the 'phosphate = algae' idea got started:

In nature there is not a lot of phosphate in the streams, but algae and higher plants do OK.
But many years ago laundry detergents had higher phosphate levels, and the processing of used water did not remove them. The treated water, released into rivers and streams was still high in phosphate. The algae grew like crazy. Then there was a big die off and the decomposing algae took more of the oxygen out of the water and the fish died. Big stench, literally and figuratively.
The scientists traced it to the phosphates, and then there was a big advertising thing about 'low in phosphates' laundry detergent to prevent algae blooms.
----------------------------------------------------------------

The truth:
Plants (including algae) MUST HAVE phosphorus to live. It is required in such large amounts it is considered one of the macro nutrients along with nitrogen and potassium.
Plants use phosphates in a ratio with the other nutrients that makes it advisable that the aquarium water test about 1 part phosphates to 10 parts nitrogen.
Since many planted tank people keep the NO3 at about 5-20 ppm, this means the phosphates should be around .5-2 ppm.

If you use root tablets then the plants can get their phosphates that way, and the tank water can test as close to zero as our test kits can show.

Since your tests are showing that the plants are removing all the phosphates from the tap water, I think you need to add phosphates to the water or the substrate.
As usual Diana to the rescue, where would we be without her?
Phosphates

Wow. Learn something new everyday. I do have a new bottle of seachem phosphorous. I will test again , and add as needed to get them up. Thanks for the info.
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