High Phosphate Levels In Tap Water

[craynerd]

I just got a phospahate test kit before i started to use the EI index and discovered very high (i.e top of the scale) - 5mg/L in my tap water!

Is this normal and what consequences will it have with me trying to start using the EI index of fertilizing?

I`m struggling understanding what i should be doing as it is, and now thats really confused me!

Chris

 

[George Farmer]

Don't add PO4 any via EI (KH2PO4) for the week.
Test for PO4 at the end of the week, just before water change.
If it reads less than 10% of your NO3 then dose PO4 accordingly.

Just a reminder for EI -

Assuming you have plenty of plants and growth, aim for -

CO2 - stable 30ppm
NO3 - 10-30ppm
PO4 - 0.5-2ppm
Dose trace on macro off-days
50% water change weekly

 

[craynerd]

Don't add PO4 any via EI (KH2PO4) for the week.
Test for PO4 at the end of the week, just before water change.
If it reads less than 10% of your NO3 then dose PO4 accordingly.

Just a reminder for EI -

Assuming you have plenty of plants and growth, aim for -

CO2 - stable 30ppm
NO3 - 10-30ppm
PO4 - 0.5-2ppm
Dose trace on macro off-days
50% water change weekly

gf255 ! I have just pm`d you since no-one was answering this, it must have been while you were replying to this message! So sorry and thanks, however there are a few more questions on there that I havent included on here.

However, i`m a little confused!?!

OK, so i dont add any PO4 for the week, but then what do you mean by ""If it reads less than 10% of your NO3 then dose PO4 accordingly"" ? Sorry to be babyish, but could u give me an numbered example (i learn easier that way!)

Many thanks

Chris

 

[George Farmer]

"If it reads less than 10% of your NO3 then dose PO4 accordingly"" ?

...could u give me an numbered example (i learn easier that way!)

Chris

If your NO3 tested at 20ppm
PO4 tested at 0.5ppm
Then you need to dose an extra 1.5ppm PO4 to reach 2ppm (10% of 20ppm).

The great thing about EI is hinted in its name - "Estimative Index". Sure loads of testing may be required in the early days but once you get a feel of what your plants need then you can forget testing. In the last three or four months of running my tank I never tested.

As long as you keep up CO2 and 50% water changes then plants are very adaptable to a wide variation of nutrient levels. IME it is stability that is more important so this is acheived by dosing daily throughout the week until the 50% water change that then resets the levels.

I understand your confusion but don't focus too much on actual test readings and levels of NO3 and PO4. Most kits are dodgy anyway (especially NO3).

In a healthy tank with lots of plants and growth, over 2WPG and stable ideal CO2 then the following regime will work in most situations. Obviously your tap is loaded with PO4 so adding PO4 may not be necessary.

Day 1 add 10ppm NO3, 1ppm PO4
Day 2 add trace
Day 3 add 10ppm NO3, 1ppm PO4
Day 4 add trace
Day 5 add 10ppm NO3, 1ppm PO4
Day 6 add trace
Day 7 50% water change

90+% algae issues are CO2 related in a high-tech tank as described. Pressurized CO2 is your best friend.

 

[Bloo]

I just got a phospahate test kit before i started to use the EI index and discovered very high (i.e top of the scale) - 5mg/L in my tap water!

Is this normal and what consequences will it have with me trying to start using the EI index of fertilizing?

I`m struggling understanding what i should be doing as it is, and now thats really confused me!

Chris

I have the same problem. However the levels in my tank are much much reduced and I'd say they were down to about 1-2mg/L (which is then pretty much "ideal") when I last tested it. Most Londoners and many other parts of the UK sit with the same problem (as well as high nitrate levels and GH/KH).

 

[Themuleous]

If your NO3 tested at 20ppm
PO4 tested at 0.5ppm
Then you need to dose an extra 1.5ppm PO4 to reach 2ppm (10% of 20ppm).

Hi Chris,

(I hope I'm not treading on your toes here George ) the easiest way to think about PO4 and NO3 is that for every 1ppm of PO4 you need 10ppm NO3, or there abouts. If you're finding that once you've done the 50% water change, your PO4 is quite high then you needn't add PO4, only NO3 to get it to the required level (dont have it higher than 30ppm, whatever your PO4 is). I guess with a tap water PO4 of 5ppm you may find you never need to add it! But practice will answer this for you.

Hope this helps.

Sam