Salt Mix, Dosing, & Test Kits

[Reefer Frank]

I've read a ton of threads related to dosing 2-part and dosing equal amounts of calcium and alkalinity. What is the consensus on the topic? What about salt mix? Does everyone try to match their tank parameters to their salt mix?

I'm using Red Sea Coral Pro Salt and have to stick with it because I bought about fifteen 175-gallon buckets during BRS' Black Friday sale.

Red Sea Coral Pro Salt tests as follows:

ALK: 10.6dKH Hanna
CA: 504PPM Hanna
CA: 435PPM Salifert
MG: 1440PPM Salifert

I am going to assume Salifert is more accurate than Hanna because back in November when I first started dosing I sent out a kit to Triton and their results were lower than Hanna in regards to Calcium. Back then my tank tested at 281PPM and Triton was 249PPM.

My tank tests as follows:

ALK: 9.9dKH Hanna
CA: 385PPM Salifert
MG: 1305PPM Salifert

I dose with the E.S.V. B-Ionic 2-Part Calcium Buffer System.

According to the "JDieck" calculator I am using, I need 312ML of calcium to go from 385PPM to 435PPM. Then, only 31ML of alkalinity to go from 9.9dKH to 10.6dKH.

I use 100-gallons as the volume even though I'm closing to 130-gallons with my sump. I don't bother to include it because I'd always rather dose less than more, just in case.

Mixed reef, more LPS than anything.

Right now I'm dosing 55ML of CA and ALK daily and 60ML of MG daily. BRS suggests that I increase calcium dosing until I balance things out, then dose equal amounts.

I am hoping that Hanna is reporting high on the alkalinity as that seems to be the case with the calcium. Triton doesn't test for alkalinity so I have nothing to compare the test kits too. Waiting on my Salifert alkalinity kit to be delivered so I can compare that to Hanna.

I'm also using my own RODI water for Hanna's calcium test, but I've heard people say they get completely different results when using Hanna's demineralized water. I could never find it but it was back in stock last week at BRS so I ordered one. My RODI is TDS zero of course.

Tank is thriving by the way, don't really have any issues. I'd still like to balance the tank out though.

I change 2-gallons of water daily via automatic water change.

What do you suggest in regards to dosing?

 

[mcgyvr]

You do not need to dose equal parts..
In a perfect world consumption is supposedly equal but this world ain't perfect..
Its very common to need to dose one more than the other..

And yes... Its "easiest" to simply choose a salt mix thats close (it should be slightly higher really) to the water parameters you wish to maintain..
If you want to maintain an alk of 9.. choose a salt mix with an alk of 10-11..
The reason for the slightly higher is so that as consumption brings your 9 down to an 8.5 the 10-11 brings it back up to 9 faster (with less new saltwater) than a mix of only 9 would..

and there are numerous calculators.. use them to have a starting dose.. then use it and then test and adjust as needed..

 

[bertoni]

I agree that there's no need to dose the two parts equally, particularly when you're trying to adjust levels. My guess is that most tanks consume alkalinity and calcium at a ratio fairly close to the 2.8 dKH per 20 ppm that the 2-parts are designed to deliver, but water changes and other processes can skew that:

http://reefkeeping.com/issues/2004-12/rhf/index.htm

Personally, I'd adjust the levels to where I wanted them, and then dose the 2 parts equally until if and when something shifts the balance.

 

[Reefer Frank]

The guide I am going by claims that if your alkalinity is increasing at a faster rate than your calcium that you should increase the dose on both, not just one.

So far, that's actually working out as described.

Alkalinity was 9.9dKH and calcium 380PPM with a daily dose of 40ML. Seems like the answer should be to scale back on the alkalinity and increase the calcium but I increased both to 55ML and alkalinity is now 9.6dKH with calcium at 395.

Hopefully it'll continue to work out that way. I test daily just in case, only takes a few minutes with the Salifert test kits.

 

[bertoni]

The supplements are adding calcium and alkalinity at the ratio I mentioned previously, 2.8 dKH per 20 ppm calcium, so proportionately, they add a lot more alkalinity than calcium. A tank can go through its entire supply of available alkalinity in a day or so, since calcification will slow down or stop as the alkalinity drops below 6.5 dKH or so.

 

[dshel1217]

I also dose in "unbalanced amount" with higher ALK but I have noticed that the CA amount has been going up slow. maybe its starting to equalize

 

[Reefer Frank]

On the 9th of February I ran a whole bunch of tests and sent that very same water sample out to Triton and received the following results.

What do you all trust? The magnesium is a bit disconcerting. Huge difference between Salifert and Triton.

I sent my water sample out on the 9th of February and sent it Priority. It arrived on the 12th I believe according to U.S.P.S. but email from Triton not until the 14th. I received the results on the 17th.

Did something affect the magnesium levels over those ~7-days, which would cause Triton to come back much lower?

Temperature on my end during the day of testing was 78, 8.1-8.2 on pH, and 35 on salinity.

CALCIUM

Hanna: 436 [Using Hanna's deionized water.]
Red Sea: 380
Salifert: 365
Triton: 352

MAGNESIUM

Salifert: 1470
Red Sea: 1380
Triton: 1308

ALKALINITY

Hanna: 9.3
Salifert: 9.1
Red Sea: 9.1

 

[bertoni]

The Red Sea and Salifert kits agree reasonably well, and I'd probably trust them. The Hanna calcium meter is known to be a bit more problematic because of the dilution, so I think it's close enough. The Red Sea and Salifert magnesium resultts disagree a fair amount. Is one kit getting older? Kits will be less accurate as they get older because water evaporates from the reagents over time.

 

[Reefer Frank]

All my kits are new. I test so much, I am constantly buying new kits or reagent refills.

On the Hanna calcium I used to use my own RO/DI until I read that the kit tests better with Hanna's deionized water but the results are nearly identical for me.

Here is what really throws me off.

I'll test my tank calcium with Hanna at 436 and Salifert at 365, so I'd assume there is a difference of 71. Then I'll use those very same kits and test my salt reservoir and Hanna reports 441 with Salifert at 440, nearly identical. I double-check the results and re-test and it's nearly identical on both.

When I use Red Sea's MyBatch on my Coral Salt Pro, they report Magnesium at 1388, calcium at 451, and alkalinity at 11.9. Salifert calcium is 435, Hanna calcium is 504, Salifert magnesium is 1440, and Hanna alkalinity is 10.6. At that point my reservoir was three days old. At fifteen days old Hanna alkalinity is 10.4, Salifert calcium 440, Hanna calcium 441, and Salifert magnesium at 1290.

Point is, on day three of my reservoir, there was a big difference between Salifert and Hanna calcium but on day fifteen they were nearly identical.

Perhaps I'm digging into this too much.

The Red Sea and Salifert kits agree reasonably well, and I'd probably trust them. The Hanna calcium meter is known to be a bit more problematic because of the dilution, so I think it's close enough. The Red Sea and Salifert magnesium resultts disagree a fair amount. Is one kit getting older? Kits will be less accurate as they get older because water evaporates from the reagents over time.

 

[bertoni]

The Hanna calcium meter doesn't have the best reputation for accuracy. The dilution step is one possible reason. I wouldn't worry very much. All of the numbers are okay.