Salt Mixing Problems

[Rog]

Hi,

I've had issues with my last 3 buckets of salt mix with calcium and/or magnesium being really low, cloudy water and precipitates.

I use RO/DI water, checked with two independent TDS meters. Input is 6ppm, output is 0 ppm. The cartridges are older but they still seem to be working well because of our low input TDS and exclusive use of cold water as per the manufacturers instructions, I presume.

First two issues were with Seachem Reef Salt. I've been using it for a few years without any problems. All of a sudden there's a white precipitate on everything in the mixing tank. Alk was way off. Tossed that batch. It was the end of the bucket so I drained and cleaned the tank and started on a new bucket. From the new bucket Calcium was a little low at 400 and Mg was 1050! Seachem support said that the minerals in the bucket may have settled and the roll the bucket on its side. I thought I would try that, but with a brand new bucket of Salinity this time. Drained and cleaned out the tank again and refilled with RO/DI. Double tested, TDS: 0.

I shuffled the contents of that bucket of Salinity into three other buckets, rolled it around, and poured it back into the original bucket. Figuring it was now well mixed and safe to use. By now the temp in the mixing tank was 17C. Each cup of salt was fully dissolved before the next was added. Water was a little cloudy, but eventually cleared after each cup. As I neared the end it stayed a little cloudy. Woke up this morning hoping it would be clear, but it is now so cloudy I can't see through it, again with a white powder precipitate on the bottom

The test I did on it last night showed:
Temp: 24C
Salinity: 35 ppt
Sg: 1.026
pH 8.65
Mg: 1080
Ca: 350
Alk 3.34

Wondering if it was my test kit, I went out and got new test kits and even borrowed the store's (a different brand) and confirmed the same results. According to seachem's website, my lot number 76409.00 should have

Salinity: 35 ppt
Sg: 1.026
pH 8.6
Mg: 1402
Ca: 430
Alk 3.3

http://www.aquavitro.com/retrieve_jpg.php?document_search=76409.00&subby_search=Submit

Turns out this is a rather old lot 12/7/15 the website says.

I'm getting really frustrated and really need to do a water change. Anybody have any idea why this keeps happening?? Either there is Magnesium missing in my bucket or something that is preventing it from being dissolved. I live in an apartment in Vancouver so I know C02 can be a factor and temperature can too. Maybe something screwy with my DI affecting Mg?

I welcome all of your ideas and experiences.

Thank you all in advance!

Cheers,
Rog

[Potatohead]

I'm going to assume that 3.3 is meq/L and not dkh?

I don't have much to say as to why it may be happening, it sounds like you are mixing in room temp water which is good... If you have any calcium chloride and epsom salt and/or mag chloride you can correct what you have but I hear you that it would be good to be better out of the gate. I have been using the Seachem salt for a little bit now and never seen this myself. With zero TDS I wouldn't imagine it is your water, but for experimentation maybe try mixing a small batch with water right out of the tap and see what happens?

[Rog]

Hi,

Thanks for your reply. Sorry yes, it is 3.34 meq/L. 9.35 dKH.

I'm setting up an experiment with tapwater and RO from the grocery store.

Rog

[SoloSK71]

Leave the water to sit for at least 24 hours with a water pump that causes surface agitation. Add a heater to bring it up to tank temperature. This can be turned off after if you are not going to use the water right away. Then when you are mixing your salt, leave the water pump and heater running for another 12 to 24 hours afterwards.

I have seen low pH water from CO2 cause problems with Calcium and Magnesium when mixing salt before. Low temperature and lack of mixing have caused issues with cloudiness/precipitation.

Charles

[Rog]

Using 145g of Salinity Salt mixed with 4L of RO (no DI) batch bought from the store:

Temp 22.4C
SG: 1.026 (Selbon refractometer - checked calibration today)
Salinity: 35ppt
pH: 8.77 (pinpoint pH monitor)
Alk: 3.17meq/L 8.9dKH (Hanna colorimeter)
Ca: 330 ppm (Red Sea Reef Foundation Pro)
M: 960 ppm (Red Sea Reef Foundation Pro)

(I validated the test kits with other test kits last night and a reference sample).

Okay, so it's not just my water that is causing this problem. This constant testing is getting time-consuming and expensive... however, I won't subject my animals to this mess and will need to keep trying and testing til I get more appropriate results.

Rog

[SoloSK71]

Just to confirm, did you test the pH before adding salt?

Charles

[Rog]

Hi SoloSK71,

Thanks for the advice on letting the water sit for 24 hours prior to adding salt.

Yes I measured the pH before adding salt, it was was 7.8.

Rog

[Rog]

I learned something very interesting in this process. my Selbon refractometer I've been using for years, although calibrates perfectly with the solution isn't quite right.

Apparently the Selbon refractometer sold in pretty much all marine aquarium stores is meant for brine solutions, and although close, isn't quite as accurate for seawater specifically. I was at J&L yesterday and tried a new bottle of 35 ppt Selbon calibration fluid on a few other refractometers. Very interesting. The sample that read 1.026 on my freshly calibrated Selbon showed 1.024 on two other refractometers...