Understanding Relationship between Alkalinity, Calcium, and Nitrates

[Randy Holmes-Farley Verified Community Expert]

I do not have a tds meter. Glad to hear I am overreacting, I will continue to hold off on dosing.

I will also recheck the alkalinity of my RO water and go to my original lfs for water. I had no issues using them before but they are a bit far away.

Might look into something like an ro buddie. Far more convenient to make your own, likely cheaper, and with better controls.

 

[shadyraro]

I recommend 7-11 dKH as a target range for alk and some salt mixes range up to 13 dKH, so it is not dangerous for your alk to rise a bit.

I recommend 400-550 ppm for calcium.

The alk may be rising if the ro water is really 2.5 dKH and looking for another source may be in order. I don’t suppose you have a tds meter to check it?

I started dosing 4 part 3 weeks ago and at the time my alk was on 8.6, it's now at 10.6 because of the red sea formula which is taken off a weekly calcium test.
My calcium (450) and mag (1440) levels are good but because alk has a 2:1 ratio of calcium, it's bumping it right up now.
I know it's easy enough to turn off the alk pump or adjust the amount dosed, but surely red sea know what they're doing here?
Or maybe something else is bumping the alk up and it's just a coincidence I started this around the same time, either way is this kind of increase doing any harm to my system? I run a LPS/softie tank and the corals are doing fine btw.

 

[Randy Holmes-Farley Verified Community Expert]

I started dosing 4 part 3 weeks ago and at the time my alk was on 8.6, it's now at 10.6 because of the red sea formula which is taken off a weekly calcium test.
My calcium (450) and mag (1440) levels are good but because alk has a 2:1 ratio of calcium, it's bumping it right up now.
I know it's easy enough to turn off the alk pump or adjust the amount dosed, but surely red sea know what they're doing here?
Or maybe something else is bumping the alk up and it's just a coincidence I started this around the same time, either way is this kind of increase doing any harm to my system? I run a LPS/softie tank and the corals are doing fine btw.

Reducing dosing of everything will allow alk to decline with hardly any noticeable change to calcium and none to magnesium.

Drop the alk to 7.8 dKH and calcium will still be 440 ppm. :)

But 10.6 dKH can be fine.

 

[NeMoo]

I’m not sure what exactly the question is, but a few thoughts…

1. Don’t try to interpret small alk or calcium changes as they may just be test error.

2. Ro/di water at 0 ppm tds has zero alk. The 2.5 dKH is test error, or the water is not well purified.

3. All of the alk and calcium values you have posted are fine. No need to fixate on a single value as perfect.

4. Instead of dosing calcium, raising the salinity to ocean average 35 ppt (sg = 1.0264) will raise calcium to natural levels.

5. In a very low demand tank, alk may rise from slow dissolution of rock and sand. If that is the case, you may want to use or make a lower alk salt mix for water changes,

Glad I read some of your post, I was always scared but noticed when I did get ATO and started to trust it I definitely see better results at that 35/1.026-1.027 range than at 1.025 I always ran from fear of high salinity but heard it on a BRS video and hearing it from Randy kinda re confirms this.

More just to get the phosphates reading lol!