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Phosphate in tapwater

James53

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14 Sep 2017
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Pembrokeshire
Hi all. I have a two ish week easy plants tank using liquid co2 and weekly tnc complete. My ammonia is nearly zero and nitrate coming good. Kh was slightly low so dosed slightly that. Phosphate is about 1 ppm on salifert test. LFS said this is high and should be about 0.25. tested tap water and that's about 1 also. Should I use NT labs anti phosphate (or similar?) Get this down from now on? Thanks
 

John q

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6 Jan 2021
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Lancashire
Hi James, I wouldn't take much notice of the advice given out by local fish stores, especially concerning planted tanks. At best they are ill informed, at worst they are trying to sell you more unnecessary products.

Plants need phosphate to survive, trying to remove it will cause deficiencies in the plants.
I add phosphate to my tanks and the levels sit around 3ppm, others dose higher rates than this and no harm comes to the fish. Also worth mentioning that phosphates at these levels DO NOT CAUSE ALGAE.

This thread might be worth a read.
Post in thread 'EI Dosing and Phosphate Level' EI Dosing and Phosphate Level
 

dw1305

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Hi all,
@James53 I agree with the other posters.
LFS said this is high and should be about 0.25. tested tap water and that's about 1 also. Should I use NT labs anti phosphate (or similar?) Get this down from now on? Thanks
I'll give them the benefit of the doubt and assume that they honestly don't know what <"they are talking about"> in this case. They might be really good with fish, but they don't know anything about planted tanks. The other option is that they know the product they've recommended is pointless, but they have <"tried to sell it to you anyway">.

To cut to the chase all you need to maintain water quality is <"plenty of oxygen"> and a <"lot of plants"> in growth, everything else is <"just froth">.

To get back to the subject:
cheers Darrel
 

John q

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6 Jan 2021
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Lancashire
Mate your kh gh ph is fine, Pembrokeshire water is fine. That bloke that sells baterd fish down the road is fine. Over reading information into planted tanks isn't fine. 😁
 
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MichaelJ

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9 Feb 2021
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620
Location
Minnesota, USA
I'll give them the benefit of the doubt and assume that they honestly don't know what <"they are talking about"> in this case. They might be really good with fish, but they don't know anything about planted tanks.

It's surely not only the average LFS that's off with regards to Phosphate. This is what the instruction reads for a very popular Phosphate test kit:
"Ideally, the phosphate level should be zero in saltwater aquariums and freshwater aquariums or ponds, including those containing live plants."

I intentionally keep my Phosphate levels at 10 ppm with my weekly dosing and been doing so for a long time now and have been able to completely eradicate GSA on slow growers such as Anubias. Fish, shrimps and plants are completely fine with this. Large unintentional build-up of phosphate (and nitrate for that matter) on the other hand usually goes hand in hand with large build-ups of organic waste due to poor maintenance.

Cheers,
Michael
 

dw1305

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Hi all,
"Ideally, the phosphate level should be zero in saltwater aquariums and freshwater aquariums or ponds, including those containing live plants."
Agreed it is a <"nonsensical statement">.

If you were interested in testing, phosphorus (P) (as orthophosphate (PO4---)) is actually one of <"the easier ions to test for">, this is because most phosphate compounds <"are insoluble"> and a <"lot of them are coloured">.
I intentionally keep my Phosphate levels at 10 ppm with my weekly dosing and been doing so for a long time now and have been able to completely eradicate GSA on slow growers such as Anubias.
We don't know why this works.

My guess would be that that the suppression of "Green Spot Algae" (GSA) is actually an iron (Fe) effect and that <"the excess of PO4--- mops up any Fe+++ ions"> before they can diffuse into the algal cells. Algae don't have any <"internal "plumbing"> and can only make use of ions that diffuse in through the cell walls.

I don't tend to have much GSA (again I don't really know why), but possibly because I have a lot of <"floating plants">, soft water and I run the tanks nutrient depleted.

cheers Darrel
 
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Andy Pierce

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Cambridge, UK
GSA is a mysterious beast. I'm happy with my current GSA status giving the aquarium walls if needed a light monthly scraping and the plants doing well. I'm convinced through direct experimentation that too much light causes GSA, but much less convinced that anything else, including phophate levels, has any material impact on GSA either positively or negatively. I have very hard water (Cambridgeshire tap), run at full EI dosing rather than nutrient depleted, and haven't got any floating plants, so quite a contrast to @dw1305. There could very well be multiple paths to success here.
 

MichaelJ

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My guess would be that that the suppression of "Green Spot Algae" (GSA) is actually an iron (Fe) effect and that <"the excess of PO4--- mops up any Fe+++ ions"> before they can diffuse into the algal cells. Algae don't have any <"internal "plumbing"> and can only make use of ions that diffuse in through the cell walls.
Very interesting.

Another thing about phosphate is how it affects real ecosystems with respect to algae growth. Around here in Minnesota the local watershed managements are tackling this by building what essentially are very large rain gardens to capture the phosphorus run-off from storm-drains, household gardens etc. before it ends up in the lakes and cause algae problems.

Cheers,
Michael
 
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dw1305

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Hi all,
Around here in Minnesota the local watershed management are tackling this by building what essentially are very large rain gardens to capture the phosphorus run-off from storm-drains, household garden etc. before it ends up in the lakes and cause algae problems.
Yes, we like these, they are <"Constructed Wetlands"> and they were one of the things that <"made me think a lot more carefully"> about aquarium filtration. I worked with <"Ana Castro-Castellon"> for a while.

cheers Darrel
 
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plantnoobdude

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17 Mar 2021
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Location
uk
thought i'd share my experience.
a few weeks ago I was experiencing horrible GSA. every week my ludwigia's lower leaves would be covered, and the tanks glass would be green and fairly hard to see through, if i don't clean it 2 or 3 times a week.
i was dosing standard EI
30, 3, 20ppm No3, Po4 and K. and 0.6ppm Fe.
i upped my po4 dosing to 5ppm/week, and this is the glass 6 days after last water change.
Screen Shot 2021-10-11 at 21.14.24.png
 

MichaelJ

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Hi @plantnoobdude Pretty impressive!!

and the tanks glass would be green and fairly hard to see through, if i don't clean it 2 or 3 times a week.
Thats another thing. I very, very rarely have to clean my glass or hardscape/equipment surfaces etc.... Granted, I do believe its a combination that makes it work; an abundance of NPK, low light intensity, proper filtration and maintenance (WC's), not just high PO4 dosing... Of course, there is never such thing as zero algae, it's just getting to the point, and keeping it there, where algae is never a nuisance that catches your eyes or is impairing plant growth or health. Thinking of our challenges in this hobby holistically and more in shades of gray, as @dw1305 puts it, seems like a good common sense approach to me.

Cheers,
Michael
 
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dw1305

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Hi all,
Thinking of our challenges in this hobby holistically and more in shades of gray, as @dw1305 puts it, seems like a good common sense approach to me.
It was really <"Diana Walstad's book"> that started me down the <"shades of grey route">. It isn't a very snappy title ("Ecology of the Planted Aquarium: A Practical Manual and Scientific Treatise for the Home Aquarist"), but as a book it does what it says it does. Ecology is all shades of grey.

Personally it isn't a very exciting, or innovative approach, but when I'm making changes I use a combination of <"experience, probability and risk management">.
In short if your plants are still growing well and you've got no algae go with it - if it ain't broken don't fix it...
In terms of making changes, I tend to go with <"if it isn't broke don't fix it"> as well.
I'd be the first to admit I'm a pretty shoddy fish keeper and because of that I like risk management. It isn't a very exciting approach, but you isolate all the single points of failure and then you try and build in extra capacity and negative feed-back loops.

cheers Darrel
 
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