Could dosing nitrates be throwing off equal parts dosing of two part?

[The Opinionated Reefer]

I am currently Dosing ATI Essentials pro and it seems to be working well. However, I am noticing that when dosing the two parts equally the calcium part is not keeping up.

For example, I am dosing 32ml of each, and if I keep my alk at 8, I want my calcium around 430 but it seems to drop to around 390/400 after a week.

At first, I thought it was because there may be inaccuracies in the dosing pumps but it's not that.

I am also dosing the ATI Nutrition part N which adds nitrates. This is designed to work with ATI Essentials pro but I read that dosing nitrates actually adds alk to your tank?

So could this be the reason that my calcium part is off? I am not dosing enough because the nitrates are actually boosting the alk?

If this is the case then you would think ATI would have provided some way to compensate for this in their dosing calculators but they just tell you to dose unequal amounts to make the calcium part meet your demand.

 

[blasterman]

Again, there is now law of marine biology that dictates calcium and alk are consumed at a perfect and consistent ratio. Its a nice place to be, but not a norm. Also, pre packaged two parts are not a good point of reference for this.

Dosing nitrate will alter a tanks biology quite a bit and can cause corals to accelerate growth. Thats why you dose nitrate, right?

Its quite possible alk was actually off before and calcium was slow and nitrate dosing has evened things out. Unless calcium is being precipitated (nitrate dosing doesn't do this) then consider this a good sign. I'm assuming you have healthy and growing stony corals in your tank. A tank full of softie frags won't consume 30points of calcium in a week...let alone a year.

 

[The Opinionated Reefer]

Yes, it's an SPS tank. The issue is that I did not see this effect to such a degree when using All for reef or a calcium reactor which are perfectly balanced.

 

[Randy Holmes-Farley]

Yes, dosing nitrate boosts alkalinity and does nothing to calcium, so it throws off the appropriateness of 1:1 dosing by requiring less alkalinity. Nitrate dosing adds 2.3 dKH of alkalinity for each 50 ppm of nitrate added this way.