Raising Ca while high dosing Mg

stevo01 · Sep 17, 2016

I tested my Ca for the first time and found I'm a little low. I'm using RSCP been 2 weeks since I've done a water change. How much will Ca rise with a 33% WC. Thanks!

Salinity - 1.0255
Mg - 2000ppm +/- 100 (treating for Bryopsis) was 1350 before treatment began.
Ca - 325-350

Tyreef2016 · Sep 17, 2016

Test your Alk. I know RSCP's salt has very high Alk. Then technically you can test the calcium in your water after mixed and then do the math.

Dustin1300 · Sep 17, 2016

Do you have a more precise measurement oustide of 325-350? With Red Sea they have it listed at 455-475 with a SG of 1.025.

Just with a SWAG based on the variations from yours and the salt mix you'll likely land in the 370-400 range. Only real way to tell is testing your water to get a more narrowed down number as well as the NSW values. Either way, that's about the limit on raising Calcium as you don't want to raise more than 50 ppm/day.

Dustin1300 · Sep 17, 2016

Tyreef2016 said:
Test your Alk. I know RSCP's salt has very high Alk. Then technically you can test the calcium in your water after mixed and then do the math.

That's a good idea too, bucket is 11.8-12.2 dHK. 33% water change could be rather impactful to Alk if much lower.

stevo01 · Sep 17, 2016

I had a feeling I was going to need to test Alk. Ok thanks.

stevo01 · Sep 17, 2016

Dustin1300 said:
Do you have a more precise measurement oustide of 325-350? With Red Sea they have it listed at 455-475 with a SG of 1.025.

Just with a SWAG based on the variations from yours and the salt mix you'll likely land in the 370-400 range. Only real way to tell is testing your water to get a more narrowed down number as well as the NSW values. Either way, that's about the limit on raising Calcium as you don't want to raise more than 50 ppm/day.

I did the wider range test on the Elos Ca test kit. (D solution would give me the a closer number) I had 7 drops of solution C. 7 X 50 = 350. For solution D, I would go 6 drop of solution C = 300. Then dial in with solution D. I'll do this tomorrow. I predict 335

stevo01 · Sep 18, 2016

Alk is 7.3

stevo01 · Sep 18, 2016

Also recalibrated my refractometer. I'm at 1.025.

stevo01 · Sep 18, 2016

Got an up-date. Will this be resolved with a couple WC's or should I dose a little in addition to WC's? Thanks!

Tank parameters
Salinity - 1.025
Ca - 400
Alk - 7.3

Fresh Mix parameters
Salinity - 1.0255
Ca - 480
Alk - 11.7

Tyreef2016 · Sep 18, 2016

Water changes will do the trick. just watch your Alk as stated before. I didn't answer before cause i know your running high Mag. I'm not sure what the impact on that will be or if you wanted to keep it high it may drop with the water changes.

Sabellafella · Sep 18, 2016

stevo01 said:
Got an up-date. Will this be resolved with a couple WC's or should I dose a little in addition to WC's? Thanks!

Tank parameters
Salinity - 1.025
Ca - 400
Alk - 7.3

Fresh Mix parameters
Salinity - 1.0255
Ca - 480
Alk - 11.7

I would execute a couple 15%ers untill calc gets to your desired range, just so alk doesnt get too high for your liking. Other then that, looks like your ok!

stevo01 · Sep 18, 2016

Thanks guys. I'll do a WC and report back. Yeah I'll probably have to dose Mg to make up for the loss in WC's.

So I found with the Elos Ca titration kit I needed to be patient. After I got a color change where it remains blue after mixing, let it sit a few minutes. It goes pink again. I dialed it in using the D solution. 1 drop. Mix and wait. Did this 3-4 times after the first initial color change. So that's why it was 350 before.

I do have a some stony corals with good growth. It's reassuring to see the Calcium and Alkalinity numbers jive with coral growth. This is where by testing I know exactly where things are and why. I'll be the first to admit I don't do enough tests.

Randy Holmes-Farley · Sep 19, 2016

In the long run it will be easier to dose calcium and alkalinity than to try to do enough water changes to maintain them.

stevo01 · Sep 19, 2016

Randy Holmes-Farley said:
In the long run it will be easier to dose calcium and alkalinity than to try to do enough water changes to maintain them.

Randy, What product do you suggest? Thanks!

stevo01 · Sep 19, 2016

I think the level can be achieved both methods. Considering that I'm dosing Mg to 2000 for a specific result, and that I have a good ammount of corals to upkeep. Extra water changes are counter productive to the treatment plan.

Thank you to all.

Randy Holmes-Farley · Sep 20, 2016

stevo01 said:
Randy, What product do you suggest? Thanks!

I'd pick either a two part, or limewater in a slow dosing ATO.

stevo01 · Sep 20, 2016

Randy Holmes-Farley said:
I'd pick either a two part, or limewater in a slow dosing ATO.

Thank you sir. Is the slow dosing mostly to avoid precipitation, or is there danger to livestock?

Randy Holmes-Farley · Sep 20, 2016

stevo01 said:
Thank you sir. Is the slow dosing mostly to avoid precipitation, or is there danger to livestock?

The pH gets too high when dosing too fast, causing both more precipitaion as well as some risk to livestock.

Adding 1.25% of the tank water volume at once (typical daily evaporation) will boost pH instantly by more than 0.6 pH units, possibly much more if the alk and pH are on the low side to begin with.

stevo01 · Sep 20, 2016

Randy Holmes-Farley said:
The ph gets too high when dosing too fast, causing both mroe precititaion as well as some risk to livestock.

Adding 1.25% of the tank water volume at once (typical daily evaporation) will boost pH instantly by more than 0.6 pH units, possibly much more if the alk and pH are on the low side to begin with.

Thanks that's good to know!