[pwu_1]

Hi, I live in Northern California, specifically city of Dublin in the tri-valley area.
I just got back into the hobby and trying EI dosing. I've noticed that my nitrates seems to always be really high no matter how much water I change out so I finally decided to test the tap water and I'm finding the nitrate test is showing maybe 5-10ppm of nitrates. Just to be sure my test kit is ok, I went out and bought some distilled water and tested that at the same time and it is showing 0 as expected.
So my question is, is it possible to have 5-10ppm nitrates in municipal tap water or could there be something else that's triggering a false positive?
And if there is nitrates in my water supply, for EI dosing, should I just dose k2so4 instead of kno3 to get potassium?
Here is a pic I took comparing the water.
I guess the next step is to calibrate my test kit using hoppys method and try and see exactly how much nitrates is in my water supply

 

[skyjacker07]

I'm in a similar boat myself, checked tank 80+ ppm on nitrates from dosing, on top of medium to heavily planted and fully stocked on fish, for the time being I'm resetting my water table, and will be dosing once a week on my macros and see how that goes, if it doesn't help then I will be dosing macros without the potassium nitrate, and see how that goes.

 

[klibs]

I'm in a similar boat myself, checked tank 80+ ppm on nitrates from dosing, on top of medium to heavily planted and fully stocked on fish, for the time being I'm resetting my water table, and will be dosing once a week on my macros and see how that goes, if it doesn't help then I will be dosing macros without the potassium nitrate, and see how that goes.

I am also doing a 'detox' of my tank. You may be interested...

http://www.plantedtank.net/forums/1...450-i-am-going-stop-dosing-my-tank-while.html

 

[skyjacker07]

I've been reading that, to be honest, when I lower my nitrates everything does a lot better, I'll get gsa, and hair or beard algae mostly on my filter intake and output, and the front glass, literally the day I do water changes it disappears, as I dose my fertz throughout the week it slowly comes back, so a once a week dosing is what I'll do, if they still get too high, I'll remove the potassium nitrate and dose the rest of the macros.

 

[pwu_1]

I followed the sticky on top and created 10ppm and 25ppm standard nitrate solution and compared it to my tank water and tap water. I guess my tap water has somewhere around 5-10ppm of nitrates and my tank has around 25ppm at the end of the week before water change.
For this week, I'm going to dose just 1/3 of the EI recommended dose for KNO3 and substitute with K2SO4 to get the potassium. At the end of the week before water change I'll do another nitrate test to see where I'm at and adjust from there.

 

[skyjacker07]

Since I'm getting plenty of nitrates from my full stock plus food, I'll be dosing K2SO4, and KH2PO4 and leaving out the KNO3 and see how that fairs.

 

[Diana]

That is the right direction to go:
Calibrate the test, minimal dosing of the nutrients that are entering the tank from other sources, and monitoring test results and plant growth.

Yes, it is possible to have NO3 in the tap water.
It often comes from agricultural areas where farmers are fertilizing their fields, and animal wastes from domestic or wild animals work their way into the water table. Here is the water quality report for Dublin, CA. There are several sources for your water, and some of them are in agricultural areas, and show some NO3.

http://www.dsrsd.com/home/showdocument?id=2340

Fish food is reasonably high in N, P and most traces. In a low tech tank with quite a few fish, the first nutrients to think about adding are K and Fe. Carbon, too, such as Excel.
When some of the nutrients come in from the tap water you will need to make up your own recipe to supplement what is missing.