I just received a response. I asked:
Many of my fellow reefers and I in the California Bay Area use Fritz RPM. We have some questions about storing the mixed salt water.
After mixing according to the product's instructions, I have been leaving it in the container with a powerhead running, with no heater. Some have noticed that without the powerhead, the water will become cloudy again with a powdery precipitate on the pumps.
Another concern we have is the gradual reduction of alkalinity over time. Initially the RPM seems to mix to ~7.5-8 dkh, but I checked yesterday after a week in storage with the pump running, and the dkh was down to 6.4.
Could you give us some insight into these questions, and your recommendation on how to best store larger amounts of mixed salt water (50g+) for several weeks at a time? I will be posting your reply back to our forums.
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Here is the response from Andy, technical sales manager for Fritz:
Hi Gabe,
Sorry for the delayed reply. I wanted to get the input of everyone on the Fritz team since this would be shared online.
First, thank you very much for choosing to use the Fritz Reef Pro Mix salt; we are hobbyists ourselves and we really appreciate the fact that you guys are fans of our product.
We have heard sporadic reports of alkalinity loss over time in stored mixes of the Fritz Reef Pro Mix salt. There have also been some, but far fewer, incidents of cloudiness and precipitation. One way we are addressing this is with the directions on the new packaging which are specific for the high parameter mix that makes up Fritz Aquatics RPM salt:
MIXING DIRECTIONS
For best results it is important to follow proper mixing instructions when using salt with elevated parameters like Fritz Aquatics Reef Pro Mix. See below for best practices when using RPM.
When Mixing Fritz Reef Pro Mix , it is best to use RO/DI water quality checked by a TDS meter (TDS should be less than 10ppm, 0 is preferred). Fill a clean mixing container (dedicated to saltwater mixing only) with desired amount of water to be prepared. For best results use water between 70° – 75°F (21° – 24°C) when mixing RPM. Slowly add desired amount of RPM to the water to avoid an increase in temperature and precipitation. This helps to prevent precipitation of calcium, alkalinity and other elements. It is recommended to use a mixing pump and an airstone when mixing RPM. This will also help to avoid concentrated areas of material and precipitation. Using a properly calibrated refractometer, bring the water to the desired salinity. Once mixed to a clear solution, add a heater to the water to bring to the current temperature of your aquarium. It is recommended to allow two hours before performing a water change. If water does not mix clear, please contact us for further mixing tips before performing a water change.
DO NOT MIX DRY SALT DIRECTLY INTO SYSTEMS WITH LIVESTOCK PRESENT!
CAUTION: Keep out of reach of children. Not for human consumption. Generates slight heat when added to water; avoid handling with wet hands. Contact with dry powder may cause skin and/or eye irritation. In case of contact, flush eyes with cool water and seek immediate medical attention.
Storage: Store in a cool, dry place. Keep product tightly sealed.
Additionally, we are actively involved in researching and responding to this but it has not been a straightforward process. For each 2,000lb lot we manufacture we pull two samples at different points in the dispensing from the blender. Those are subject to QC testing before we package. Our standard QC test looks like the following:
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If the salt does not meet our specifications at this time, it is not packaged. If it does, we package and ship the salt. To the best of my knowledge we have the strictest QC in the industry.
When we are contacted saying there is a loss of alkalinity or precipitation we work with the customer to ascertain if anything on their end has contributed to this. Because our salt is on the high end of the critical parameters it really needs to be used with purified water. Many issues are resolved when it is shown that the mix water has a starting alkalinity of 5 or higher dKH. Other issues have been traced to mix containers having a layer (sometimes virtually invisible) of the previous sea salt inside. If calcium coats the walls of the mix container and Reef Pro Mix is added alkalinity will drop as insoluble calcium carbonate falls out of solution.
Additionally we recommend checking the alkalinity, pH and TDS. In some cases carbon dioxide can build up resulting in lower pH which can erode alkalinity. You want a neutral pH, no measurable alkalinity and 0 TDS. However, at this time we don’t have data to indicate the frequency of this arising as an issue.
In rare cases, the concern is not resolved at that step. Right now we have a few situations like that we are exploring. What is puzzling is that in our laboratory with the retain samples from that specific lot, we have not been able to reproduce what the customer is reporting. Our mixes are not going cloudy and the alkalinity is remaining stable over several days. We have done testing where we selected random lots and pulled over a dozen samples per lot to see if blending is consistent and it is – variations of about 15 ppm in Calcium and 30 ppm in Magnesium are common over an entire lot. Alkalinity is a little more fluid, we do see differences of up to 0.5 dKH in a single lot.
We’re now in the process of getting salt and sample mix water with and without salt from affected consumers to analyze. This process will take a bit of time.
Even though the customer contacts received to date represent less than 0.00004% of the salt sold, we are committed to addressing them and either resolving the customer’s issue at their end or ours so that all users of Fritz ProAquatics Reef Pro Mix achieve the best results possible in their reef.
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