Mixing Saltwater

[readingbabelfish]

Hello,

I usually mix up my saltwater in a 30 gallon tote. When it gets low, I just add more ro water and mix. So it is always ready to use during a water change. I have noticed the water when freshly mixed has an alkilinity of 11 or 12, but a few days afterward, its alkilinity goes down to 6 and there is a white film on everything in the tote, heater, pump... Is this a bad practice and how can I get the alkilinity back up to where it should be?

thank you

[Steve McKay]

Hello,

I usually mix up my saltwater in a 30 gallon tote. When it gets low, I just add more ro water and mix. So it is always ready to use during a water change. I have noticed the water when freshly mixed has an alkilinity of 11 or 12, but a few days afterward, its alkilinity goes down to 6 and there is a white film on everything in the tote, heater, pump... Is this a bad practice and how can I get the alkilinity back up to where it should be?

thank you

That is normal. If your tote is colored it may leach chemicals, make sure you use a clear container.

[metalhead]

The white film is likely calcium that's precipitating out of solution as the alkalinity falls. You might try using some alk buffer which may help maintain a good level. The fact that it drops so quickly makes me think that there's something else going on. As Steve points out, make sure your container is food grade or better so nothing's leaching into your make-up water.

[Steve McKay]

The white film is likely calcium that's precipitating out of solution as the alkalinity falls. You might try using some alk buffer which may help maintain a good level. The fact that it drops so quickly makes me think that there's something else going on. As Steve points out, make sure your container is food grade or better so nothing's leaching into your make-up water.

So far I haven't had a problem with that except for cleaning the pump. So far it also doesn't affect my Ca or Alk level when I do a water change. I don't add Ca, Alk or Mg to the new water, I test for Ca and Alk in my tank before and after along with the rest of the testing and the level of Ca and Alk remained the same. Maybe I'm just lucky I don't know. Lately I haven't needed to add Mg because the water changes have kept it above 1280 which is where I want it.

[Ninong]

I usually mix up my saltwater in a 30 gallon tote.

You should use a Rubbermaid Brute container in gray, yellow or white only. Those meet federal food container specs. The others do not and it's possible they could leach chemicals into your water. This is especially important when storing R.O./D.I. water and somewhat less important when storing saltwater. R.O./D.I. water will really draw out chemicals, especially if the container is new and it is not one that meets USDA food-container specs.

When it gets low, I just add more ro water and mix.

This is not a good policy. You should rinse out the container after each use, using vinegar in the rinse water in other to remove any calcium deposits that may have accumulated on the walls of the container. Using a white Brute container works best because you can easily see any sediments (clay) that may have settled to the bottom of the container. Some brands of salt mix are known for leaving calcium deposits on the walls of the mixing container (e.g. Instant Ocean).

So it is always ready to use during a water change. I have noticed the water when freshly mixed has an alkilinity of 11 or 12, but a few days afterward, its alkilinity goes down to 6 and there is a white film on everything in the tote, heater, pump... Is this a bad practice and how can I get the alkilinity back up to where it should be?

When freshly mixed, the alkalinity will usually be higher than it will be an hour or two later, assuming you do things properly. You should mix the saltwater by starting out with good R.O./D.I. water that has been raised to the proper temperature. You should add the salt mix no more than one cup at a time, stirring well after each addition. You should then stir the saltwater vigourously for a good 30 seconds. Then you should allow it to 'age' while circulating the saltwater with a powerhead or a strong airstone. Cover the container but allow the lid to be slightly open so that there is at least a 1/2" opening to allow air to enter. This is important to equalize pH.

Obviously at some point you will need to check the salinity of the mixed batch of saltwater. I used a refractometer. I always mixed an 18-gal batch in a 20-gal white Brute container. I had a line marked inside the container to identify the 18-gal level. I knew exactly how many cups of my preferred brand of salt mix it would take to give me salinity of approximately 35 ppt. I usually checked my salinity about an hour after mixing and would adjust it at that point by either adding a little more R.O./D.I. water or a little more salt mix. I was always so close that an adjustment was usually not necessary.

You should never used freshly mixed saltwater except in the case of an emergency situation where you have no choice. Saltwater should be aged for three to seven days before being used but at least 24 hours. Using it immediately or even one hour after mixing it is really bad advice, no matter what the manufacturer's instructions may say.

[Steve McKay]

You should use a Rubbermaid Brute container in gray, yellow or white only. Those meet federal food container specs. The others do not and it's possible they could leach chemicals into your water. This is especially important when storing R.O./D.I. water and somewhat less important when storing saltwater. R.O./D.I. water will really draw out chemicals, especially if the container is new and it is not one that meets USDA food-container specs.

I don't know about those containers Ninong, somewhere I read an article about some people collecting gametes for research and they were using gray Rubbermaid Brute containers which they had in the past and they were having problems. They took gametes from different containers that they weren't having problems with and when added to the brute container they became inactive and died so to speak.

[Ninong]

Steve,

Are you using pyrex glass containers to mix your saltwater now?

I wonder why anyone would use Rubbermaid containers to conduct larval research, or whatever they were conducting?

I'm sure there are other plastic containers that would work just as well for mixing R.O./D.I. water and/or saltwater but the Rubbermaid Brute containers (in gray, yellow and white only) have been very popular for more than the past 10 years now. Those are the only Rubbermaid containers that meet all of the food safety specs for storage of food.

Rubbermaid containers contain a large percentage of recycled plastic. In order to satisfy the government's specifications for food-storage containers, the manufacturer has to be careful what used plastics are included in the recipe. This doesn't mean that other colors of Rubbermaid Brute containers can't possibly work just as well, only that they may not always work just as well because you can't be sure what went into the mix when they were made.

This issue has come up a lot over the years when some members have posted that their green Rubbermaid Brute did not leach anything into their R.O./D.I. water as claimed by other members who actually measured very high TDS in R.O./D.I. water a couple of days after mixing it in their green Rubbermaid Brute container. This explanation came directly from conversations with the manufacturer. Only the white, yellow and gray Brute containers always meet USDA food specs. Sometimes other colors of Brute containers may be just as good, depending on what went into them.

[Steve McKay]

Are you using pyrex glass containers to mix your saltwater now?

And I have them sterilized professionally. No I use Sterilite clear plastic containers that I do clean after each use. I know the brutes are food grade and should be good to go. The people involved had used them before without problems but they bought new ones and started having problems, they must have been contaminated somehow either during manufacturing or after.

[Ninong]

And I have them sterilized professionally. No I use Sterilite clear plastic containers that I do clean after each use. I know the brutes are food grade and should be good to go. The people involved had used them before without problems but they bought new ones and started having problems, they must have been contaminated somehow either during manufacturing or after.

I just wonder why anyone would use Rubbermaid containers for research? After all, they do contain recycled plastics. Just because they meet USDA specs for food storage doesn't mean they should be used for delicate research projects. I always thought they used glass containers for stuff like that???

[Ninong]

I use Sterilite clear plastic containers that I do clean after each use.

Aren't all Sterilite containers food-grade HDPE? The same stuff our milk jugs are made of? I think they all meet USDA and FDA specs, the same specs that the Rubbermaid Brute gray, yellow and white containers are certified to meet.

We got involved in a lengthy discussion and investigation of this issue some nine or ten years ago when one of our members purchased a couple of brand new Rubbermaid Brute containers in the common greenish color that you usually run into at Home Depot. He measured his freshly producted R.O./D.I. water as zero TDS. Then he measured his R.O./D.I. water about a week later just to make sure nothing had caused it to "go bad" during storage and was surprised to measure something like 175 TDS. He called Rubbermaid and talked to someone in their chemistry or engineering department and they told him he was using the wrong color Brute container and they explained why.

[Steve McKay]

I just wonder why anyone would use Rubbermaid containers for research? After all, they do contain recycled plastics. Just because they meet USDA specs for food storage doesn't mean they should be used for delicate research projects. I always thought they used glass containers for stuff like that???

That I don't know. It would seem to me that one would use glass or a similar material that can be sterilized. I tried to find that article but know luck.

[Steve McKay]

Aren't all Sterilite containers food-grade HDPE? The same stuff our milk jugs are made of? I think they all meet USDA and FDA specs, the same specs that the Rubbermaid Brute gray, yellow and white containers are certified to meet.

I don't know, but they probably are. I figured that a clear plastic container would be the safest.

[Ninong]

So the Sterilite container you are using is one of those boxy looking food-storage containers? Or do they make a food-storage container in a large drum shape like a Rubbermaid Brute?

Obviously anything sold for food storage would have to meet all of the US goverment specs for food safety.

[Ninong]

There are professional storage containers that you can purchase for storing R.O./D.I. water or saltwater in large quantities but they are quite expensive. Most people have found the Rubbermaid Brute containers (white, yellow and gray only) to be an inexpensive choice in the 32-gal and 20-gal sizes. Anything larger than 32 gallons is really too large to handle easily. I had a 32-gal Brute (gray) and two 20-gal Brutes (white) and I almost never used the 32-gal because it was too big to deal with compared to the 20-gal ones.

[Steve McKay]

There are professional storage containers that you can purchase for storing R.O./D.I. water or saltwater in large quantities but they are quite expensive. Most people have found the Rubbermaid Brute containers (white, yellow and gray only) to be an inexpensive choice in the 32-gal and 20-gal sizes. Anything larger than 32 gallons is really too large to handle easily. I had a 32-gal Brute (gray) and two 20-gal Brutes (white) and I almost never used the 32-gal because it was too big to deal with compared to the 20-gal ones.

When I had my 125g, I used containers that were about 50-55g for my ro/di water and for mixing but I don't remember what kind. That was 20 years ago. I would put one next to the tank and use a bucket to fill it then mix. Now that the water changes are weekly of 5g, I just use 8g Sterilite clear containers for mixing and storing my distilled water. I distill my own water because it gets everything out unlike ro/di which is good water too don't get me wrong.

[Chrissy]

I have been using my old 5 gallon buckets and a drinking water bottle purchased at wall-mart, should I expect any problems?

[Steve McKay]

I have been using my old 5 gallon buckets and a drinking water bottle purchased at wall-mart, should I expect any problems?

Probably not but I would recommend clear plastic containers preferably made of food grade material.

[Ninong]

I have been using my old 5 gallon buckets and a drinking water bottle purchased at wall-mart, should I expect any problems?

Certainly not from the drinking water bottle and probably not from the "old 5 gallon buckets." What came in the "old 5 gallon buckets" or did you purchased those separately?

[zhenya]

That I don't know. It would seem to me that one would use glass or a similar material that can be sterilized. I tried to find that article but know luck.

Steve, it wasn't really an article but a rather lengthy thread on another website. It was started by Eric Borneman and you can read it here. I believe I mentioned something about this thread before, somewhere in your thread maybe?

Anyway, they simply collected gammets and after placing them in those containers most if not all had died.
Something like that...
I store my RO/DI water in the container(40g) specifically designed for it, which I bought at one of the sponsors here. Can't remember which one but most likely it is no longer a sponsor here, maybe it was AquaFX or something like that. It was at aleast 5 to 6 years ago. I never had any issues with it either.
I'm looking to buy different container for mixing salt water but haven;t found one yet. Planning a trip to the restaurant supply store that is local to me, maybe I can find something there. They don't sell to the public, usually, but I have many friends that own restaurants so I should be able to get something through them.

[zhenya]

Here's an interesting post from that thread I mentioned in regards to "food grade" and "FDA approved" stamps on the plastic containers:

I did a bit of research on what "FDA approved food safe", or similar labeling, means.

I spend a lot of time working with the FDA on biologics, so I know a lot of reviewers and have calls into some of them, though I don't know yet if they will be able to answer food container questions. In the meantime I read through a number of section of Title 21 CFR (code of federal regulations) to see what I could find on food containers.

What I have found is the FDA has a list of approved substances that may directly (additives) or indirectly (packaging) contact food. The list is fairly long but referenced in the linked section of 21 CFR 177- container seals.

The section references and shows a common list of "approved compounds". The list is remarkable in what "they" are allowed to feed us, but reflects the necessary allowances for trace (or not so trace) solvents, polymers, etc. that inevitably come into contact with our food during the manufacturing process.

The take home message is that the regulations, and "approved" labeling only means there are not sufficient levels of any of these numerous known toxic molecules to cause harm to humans when consumed in low to modest amounts. The regulations DO NOT mean to imply that they are not present or that nothing will leaching from a container, or that what does leach isn't toxic to sensitive organisms - sperm or corals, at the allowed levels.

Further, there is nothing in the regulations (that I have found) that specifically requires a container manufacturer to demonstrate consistency of the levels of each of the known approved contact agents if they are below acceptable levels. In other words, minor manufacturing changes could produce containers that have lot to lot variability in toxicity for these sensitive organisms and our reefs.

Lastly, I hope to confirm, but my research so far suggests there is no definable or demonstrable difference in "safety" between a Brute "approved trash can and a $500 "potable water" container. Both are subject to the same regulations and both ostensibly meet the guidelines. I would speculate that a cheap "FDA approved" HDPE/LDPE container is made pretty much in the same way as an expensive HDPE/LDPE container meaning the trace contaminates and leaching may be similar.