New salt test results

[Bpb]

Well through my first year of reef keeping I managed to make one 200 gallon box of Instant Ocean Reef Crystals last just about the entire time. Granted, toward the beginning I was doing weekly 10% water changes, sometimes more. I wasnt always mixing it to the correct salinity because I didn't have a refractometer, and was generally inconsistent. I am still new but in my first days, I assumed "I want a reef, so I'll use reef salt" even though I could have gotten away with plain old Instant Ocean Sea Salt. My tank was mostly fish and zoas for the bulk of it's young life.

Since I've taken on testing, dosing, and SPS keeping, I decided to start testing each batch of that 200 gallon box toward the end of its use. The levels were startling. While, this was the final of 4 bags in the box, I can only assume the others were similar. When mixed at 1.023, that box of Reef Crystals was testing consistently at 8.2 dKH, 360 ppm Calcium, and 1100 ppm Magnesium. I'm using the Red Sea Pro tests for these, and have a good handle on how to use them. I'm about 100% positive this is not user error. I understand the color shifts, I'm not color blind, and I know how to measure titrant displacement. So those levels were quite a bit lower than advertised. I got tired of buffering each batch I made in order to not lose any of those ions that I'd have to go back and dose later.

I was torn on what salt to purchase when this box was done with, and considered mixing several brands. I don't water change but maybe 10% a month now at this point, so I decided to just give Reef Crystals another try.

Talk about inconsistent results. Using the same test kit (less than 6 months old, and has been used on many other tanks and against other kits to verify). This time I purchased a bucket instead of a box. The bucket left about 3" of empty space at the top. Perfect for me to tumble the bucket, roll it around, and make sure the salt was good and mixed. I know salt mixes aren't a homogenous mixture, so some crystals can settle at the bottom. Just mixed up a fresh batch using 0 tds RODI water. Here are the results:

1.026 salinity

12.2 dKH

480 ppm Calcium

1480 ppm Magnesium

Looks like I probably could have gotten away with just getting regular old Instant Ocean and saved myself $10. Doing a water change today. Those parameters are a good bit higher than I've kept my tank. The tank is currently at

1.024 salinity

8.2 dKH

430 ppm Calcium

1400 ppm Magnesium

I'll likely just add a little extra RODI water to the salt mix to dilute it some. The alkalinity worries me a little bit, but if I mix the salt at 1.024 instead of 1.026, and only change 10% a month I don't think that'll throw things off too much will it?

Anyhow. Thought yall might be interested.

[+olaggie01]

How big of a tank are you running and how much is 10%. A 10% water change shouldn't affect the alk in the tank too much.

[Bpb]

55-60 gallon total water volume. 6 gallon water change.