Re: 40ppm

[Thomas Barr <tcbiii at earthlink_net>]

> Unlike me...
> 
> I also suffer from local tapwater that tests 40ppm Nitrate so I'd ideally
> like to find something that at least slows down the rate of Nitrate increase
> in my tank without having to go to the extra work of RO & having to
> reintroduce GH, KH etc.
> 
> & I like fiddling with gadgets.
> 
> Kevin

So a 25% weekly water change allows you not to need KNO3. Add K2SO4 instead.
Crank the CO2. The NO3 will fall unless you have higher fish stocking
levels.
If you have a well growing tank, adding 10ppm NO3 to your tank(assuming the
tank is 0ppm) adding 25% at 40ppm will give 10ppm.

Need to fertilize? Do a water change. Same thing applies to PO4.
If you test, I think you'll find this to work well.
If you really need to do larger water changes, mix with the RO.
But you should be able to do 25% weekly changes, no problem.
Regards, 
Tom Barr