Nitrate in tape water - strategies

[drdetroit]

My local water district reports about 9.8 mg/L nitrate in my tap water. This shows up on my test kit as around 40ppm.

So I wonder does it make sense to adjust the EI fertilizer dosing to accommodate the nitrates already present?

Would it be better to use a media like Nitrazorb on each water change to lower the nitrate levels before dosing?


There are fertilizers and pesticides and who knows what else that have leached into the local water table. I guess the safest thing is to use RO water or perhaps a combination of RO & tap and then buffer it up so I can use CO2. However I wonder how important this really is as I've been breeding fish and shrimp in this water and I haven't seen any serious health issues (yet).

 

[VaughnH]

Your test kit may be wrong if it says you have 40 ppm (mg/L) where the water company says it is more like 10 ppm. If the water company is correct you can just dose EI normally - the plants will consume the nitrate in any case. If your test kit is correct you could skip a dose or two of nitrate and still have enough. In any case, removing the nitrate so you can add nitrate doesn't make sense.

 

[drdetroit]

Ugh. I see I misspelled the title.


Thanks for your input. I think I'll run with it. My concerns are, of course, that if the test kits are correct 40ppm is high to start off with before adding generous fertilizers and running a biological filter. Also I wasn't sure if the Nitrate in the tap was fully bio available. You're far from the only person who feels it is. Unless proven otherwise I defer to your judgment.

I understand that the test kits are not always to be trusted. However I have tried 2 brands that basically agree with each other. Also I have noticed significant fluctuation over the year of under 20-40ppm. (the test kit is in 10ppm increments). The cynic in me wonders if the published sample was lower becasue they cherry-picked the lowest of their samples and I generally question the relevance to what actually reaches my tap on a regular basis. I guess all I can do is continue to play with things in my tank.


It's interesting to note that the local water company claims the source of the nitrate is leaching of septic systems into the water table.
Yuk! (No wonder they chlorinate the heck out of the water)