High Nitrate

[Doc7]

C101 -

Even if it's 5 ppm a week...if you change the same amount of water each week the amount of nitrates will constantly build based on my INCORRECT math above.

messing with excel, i just realized the obvious point where removing some % of the water each week, you will eventually hit a point where the 20-30% you remove is exactly equal to the amount that was added over a week. For example, with 20ppm/week doing 25% water changes, once you hit 80 PPM nitrate, replacing 25% of the water removes 20 ppm so you will see a cycle each week from 60 ppm post-w/c to 80 ppm pre-next-w/c.

d'oh

 

[Curiosity101]

It depends on alot of things as to where you find a balance of water change vs bioload. But yes... you can have a water change that lowers the level enough that it only reaches the same level each week.

I know this from 1. Working it out mathematically and 2. Owning tanks and seeing other peoples tanks.

It's definitely an odd concept to get your head around at first, so don't feel silly for questioning it.

 

[Doc7]

So, basically from what I gather, once my tank is stocked, I can perform nitrate tests regularly until I find the point where the volume of water changed weekly, for my particular live-stock and feeding habits that my nitrates stay in the sub-30 ppm range?

I have a playsand substrate so I suspect, but don't know for sure yet, that I will be performing gravel vacs more than weekly anyway to get rid of poo. I don't really look forward to that (and the negative-"show" qualities said poo will have if I have unexpected company, etc) but I really want pygmy cories after reading much about them!

 

[Curiosity101]

So, basically from what I gather, once my tank is stocked, I can perform nitrate tests regularly until I find the point where the volume of water changed weekly, for my particular live-stock and feeding habits that my nitrates stay in the sub-30 ppm range?

Pretty much yes.