Phosphates 2.5+ in my tap water.

Mark.A

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22 Jul 2009
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55
Location
Northumberland, UK.
Hey all, I am currently cycling my tank and whilst I was testing the tank water for ammonia I figured I'd test my tap water for Nitrate and Phosphate. Nitrate is almost zero (maybe 1) but Phosphate is 2.5 possibly slightly more.

I was planning to dose TNC Complete once the tank is setup but now I'm thinking that's going to be no good because of the already existing Phosphates in the tap water. Can someone confirm this is the case?

I will be doing 50% weekly water changes to reset everything but as the tap water has Phosphates in already it will be resetting the Phosphate levels back towards 2.5-ish once I do the weekly water change.

If the TNC complete is no good I presume I will be best making up my own EI mix? Any advice on what I would need to mix taking into consideration the existing Phosphate?
 

Zeus.

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1 Oct 2016
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Yorkshire,UK
I personally wouldn't trust a test kit What about Test Kits ?
Getting you hand on your water report form your water supplier is the best bet, then see what the seasonal range is for PO4 and use the lowest value.
Then use that value to calculate how much PO4 your adding with your weekly water change.

Just so happens that my new fert calculator does all the maths for you

eg
upload_2020-4-21_11-52-57.png

Not only does it do that it does all the maths for you to 'clone' some commercial ferts (the pics below did not have any PO4 in the tap water added )

upload_2020-4-21_11-55-35.png


then gives you the salts to add to your dosing bottles for your tank, if the salt isnt need to reach the weekly ppm target than it doesn't use it

upload_2020-4-21_11-56-50.png


and a complete report on whats been added from salts and WC over the week, plus allows you compare other fert regimes

upload_2020-4-21_11-59-45.png


So making your own DIY ferts has never been easier IMO

Zeus
 

Zeus.

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1 Oct 2016
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Yorkshire,UK
I already checked the water quality report. I have one from 01/01/2018 to 31/12/2018 but it doesn't have PO4 on it at all.
Same here so trust your water report and not your test kit, ferts in excess isnt a problem as long as you do a WC to suit your fert regime ;)
 

Mark.A

Member
Joined
22 Jul 2009
Messages
55
Location
Northumberland, UK.
Same here so trust your water report and not your test kit, ferts in excess isnt a problem as long as you do a WC to suit your fert regime ;)
No, I don't mean the water quality report says there is no PO4. I mean that the level of PO4 is not in the report at all.

So what you're saying is it doesn't matter if there is too much PO4? ...and I can just dose the TNC Complete and not worry about the extra PO4?
 

Zeus.

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1 Oct 2016
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Yorkshire,UK
Well heres a comparison of EI fert dosing and TNC

upload_2020-4-21_12-33-33.png


So even if your test result is correct 2.5 + 0.62 = 3.1ppm PO4 thats only 0.1ppm above the EI upper range for PO4

So what you're saying is it doesn't matter if there is too much PO4?
In your case yes, there are upper limits OFC, but cant see you hitting them :D
 

Sammy Islam

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12 Mar 2019
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365
Location
Hertfordshire
No, I don't mean the water quality report says there is no PO4. I mean that the level of PO4 is not in the report at all.

So what you're saying is it doesn't matter if there is too much PO4? ...and I can just dose the TNC Complete and not worry about the extra PO4?
No need to worry about the po4. If you plan on dosing EI levels with TNC complete, the po4 in your tap water will actually help because TNC complete is low in po4 when dosing to EI levels.
 

dw1305

Expert
Joined
7 Apr 2008
Messages
9,798
Location
nr Bath
Hi all,
but it doesn't have PO4 on it at all.
There isn't a statuatory requirement to report it. There isn't a maximum permitted value for phosphorus (P), or orthophosphate (PO4).

It is the same with magnesium (Mg). We are interested in its level, but there aren't any statuatory limits, so most water comapnies don't report its level in your tap water.

Because of the low NO3 value it is unlikely there is much PO4--- in your source water, but your water company will have added somewhere in the region of 0.5ppm PO4---, along with sodium hydroxide (NaOH), to control the levels of lead (Pb), zinc (Zn) and copper (Cu) the technical term is phosphate induced metal stabilisation (PIMS) for the <"control of "plumbosolvency">.

Have a look at <"Public water supplies in the Northern region of England July 2016">.

cheers Darrel
 

Zeus.

Member
Joined
1 Oct 2016
Messages
3,011
Location
Yorkshire,UK
Maybe fix the typo in the spreadsheet? Says 'tMc' in the picture.
Better not confuse people about ferts, it's confusing enough already!:crazy::crazy::crazy:
l

Cheers m8 :clap:

One of the joys of being dyslexic - your mind auto corrects everything into what it thinks it should be, so spotting typos is hard:oops:
 
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