Mixing reef salt mix, the best method for the saltwater aquarium - FAQs

June 5th, 2019
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Mixing reef salt mix CORRECTLY will result in less precipitate and brown crust in your mixing and storage containers, more stable initial water parameters and presumably avoid any negative health benefits associated with dosing undissolved salts into your saltwater aquarium. It is safe to assume exposing fish gills and coral tissue to undissolved salt crystals is not healthy, even if it isn't immediately toxic.


Reef Tank


We are not talking about the bare minimum process to mix salt and keep the tank alive. Instead, we want to provide all of you with the absolute best practices for mixing saltwater yourself for optimal parameters and reduce build up in your mixing and storage bins


Over the last few months, we have been performing all kinds of salt mixing experiments. This is essentially the combined results from many of those experiments and in typical BRS fashion, there will likely be more coming so keep an eye out as this story progresses.


Red Sea Coral Pro Instructions


Follow the instructions, it’s a no brainer!

The first thing we learned is you should always follow the instructions on the bucket, they are printed for a reason. All of these salts come from different sources of mined, evaporated or purified synthetic salts and have different levels of major elements. Some even contain extra additives such as chelators and clarifiers which will change how the salt mixes up.



While all of the available salt mix options we carry will support marine life, they are not the same, particularly when it comes to the mixing process. Some are less dependent on strictly adhering to the instructions for optimal results but if you are looking for best practices, the manufacturer is going to be the best place to start.


Mixing saltwater in a bucket


Mixing Saltwater

We asked the reefing community over at Reef2Reef how long they mix their salt and for such a necessary process, the answers were surprisingly all over the place. 29% of you said you only mix for an hour or less, another 3rd of the poll participants said 12 hours or more, so which one is correct?


BRStv Investigates Salt Mix Clip 1


In our experiment of unheated water with two powerheads mixing up 20 gallons of saltwater, the necessary length of time to create visually homogeneous saltwater varied dramatically. Starting at around 7 Hours to many of the salts not even fully dissolved at 24 hours.


Considering many of the salts we mixed were not fully homogenized or dissolved at 24 hours, I think the best general advice is to mix it for 48 hours.


Helpful Tip: This means you need to plan ahead at least two days before a scheduled water change and even longer if you need time to collect purified freshwater using an RO/DI system.


8 Brands of tested salt mix


As mentioned above, we tested 8 different brands of salt mix and the results varied widely in terms of exactly how long each salt mix needed to fully dissolve. These are the brands that successfully mixed in less than 24 hours which is beneficial for those of you looking for something that will mix up a little quicker.



The only thing to note here is the two powerheads warm the water to around 76° F on their own but we did NOT add an aquarium heater to the water during this test. Some salt mix brands do call for heating in the mixing instructions and using a heater set at 78° F may produce some benefits with certain salts, particularly if they call for it in the instructions.


Storing Premixed Saltwater

Storing the water properly is important because many of us are mixing large batches of saltwater and storing it for use throughout the month; if not stored correctly the chemistry of the water may change resulting in varying tank parameters.


Aquarium with salt mix


Do you need to heat the water during storage?


Again there isn't a one size fits all answer to this one. Our experiments show that the best practice answer to that question is, yes, but probably not forever and not with every salt.


In our first experiment, we only mixed the salt for just an hour with a pump and no heater, then monitored for both measurable and visual signs of precipitation or undissolved salt particles over the course of weeks.


BRStv Investigates Salt Mix Clip 2


At the end of those weeks almost all of the tested salt mixes left a fairly thick white crust at the bottom of the container. The only exception was Tropic Marin Pro that was identical to the clarity of pure RO/DI water with no visual undissolved salt or precipitation.


BRStv Investigates Salt Mix Clip 3


We repeated the same experiment with both heat and flow and all eight were virtually free of any precipitate or undissolved salt on the bottom. Even after we pulled the plug on the heat and flow, weeks later the salts remained mixed without the white crust.


So the obvious next question is, was it the heat or the flow that helped reduced precipitation during storage?


We repeated the experiment again with no heat but mixing for 24 hours and then pulling the plug on the flow. For most of the salts, 24 hours of flow and mixing seemed to produce no signs of precipitation after weeks of storage. Again, the pumps alone in small glass boxes do add some heat.


After all of this testing at the same specific gravity, we recommend heat and flow for at least the first 24-48 hours as a best practice for all salt mixes.


Tropic Marin Pro Reef and Brightwell Aquatics NeoMarine Salt Mix


It can be scaled all the way down to one hour of mixing with no heat for select high quality salt mixes, most notably Tropic Marin Pro Reef and Brightwell Neomarine. Both of which seemed to repeatedly perform well in all the experiments and probably require the least amount of time, equipment and effort to mix and store.


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