Something's Wrong With My Salt Mix

[idlefingers]

Yesterday I bought a cheap 80ltr tank to mix salt into and heat the water for water changes. I added 50 ltrs RO from my own RO/DI unit with TDS of ~200ppm in, 0ppm out. Then weighed the amount of salt (Seachem Reef Salt) which was advised on the tub of salt and put it in.

It's been mixing with the heater on now for about 30hrs and while the water is starting to clear up a little, theres what looks like quite a bit of salt dust on the base of the tank and on the heater. The top of the water looks very dusty and there's a kind-of brown gunk which has settled at some points around the edge of the water line.

I was just about to email seachem and see what they say but thought I'd see what you kind folk think first. Could it be my RO? Something on the tank (It was brand new and I rinsed it out)? Something on the equipment (which had been used before)? Something else?

 

[SkiFletch]

Something on the equipment (which had been used before)?

That explains the gunk on things. Remember, when first mixing, fresh saltwater is somewhat chemically volatile and can easily strip gunk off a heater or powerhead and spit it into the tank. Also remember that Pure RO water is a very good solvent, so if you put the heater/powerhead in the tank when RO was in there, or even before the salt was added, its quite possible that the RO dissolved some of the organics on the equipement leading to the nasty stuff.

Dust is normal if you leave it open topped

The "salt dust" is either un-mixed salt, or calcium carbonate deposits from areas of supersaturation during mixing. Buckets used for longterm salt mixing will eventually be coated in calcium carbonate, this is totally normal.

 

[idlefingers]

Cheers for that ski! I didn't realise the RO water could do that.. it had been in the tank for a little while before the salt and while I did clean the heater/powerhead, I didn't do that good of a job so I guess that was the cause. I have a condensation cover on it to keep dust out, so it definitely wasn't normal house dust.

I've emptied it and given everything a really good clean and scrub. I've just filled it with RO and then put the salt in straight away so hopefully it'll go better this time!

Thanks again skifletch!

 

[sophos9]

I've gone from making big batches through to adding salt in a 15ltr bucket 5hrs before adding to tank, salt totally disappears and all looks groovy - not floating fishes so must be OK!!

 

[idlefingers]

A wee update for anyone who's bothered.. I continued to have issues with the salt mix and decided to email seachem last week to see what they thought. Here's what they said:

It sounds like there is some precipitation in the mix from the ring around the tank and some settling. Any particles precipitated are not harmful. Try mixing the salt with water and allowing the water to come to room temperature or a powder head that may be less forceful.

So I've downgraded to using a less powerful powerhead and mixing it slower and without the heater on at the beginning and it seems to be a bit better with that but is still a bit odd...

I've been experimenting with it and it seems to be that after 48hrs mixing it does this (the dust on in the tank and on the top of the water) but then after 72hrs it mostly seems to clear up again. A lot of the original gunk was due to remnants of dirt on the equipment from it's freshwater use as ski suggested and the second attempt after cleaning was much better, but it still seems to have the odd 48hr point.

I did a water change with it last week and will be doing the second tomorrow and all seems well so far so it just seems to be some sort of oddity related to either the way I mix it or the seachem reef salt. So long as it doesn't do anything bad in my tank, I can get used to it..

 

[xxBarneyxx]

Interesting to know and thanks for posting the update. Helps me to know what to avoid/look out for when I get going

 

[sophos9]

Seems strange... even with the cheap salt I'm using, it mixes within 30mins...?

 

[idlefingers]

'tis strange.. It does mix quite quickly and after a couple of hours seems okay and could probably be used but it says it's advisable to mix for at least 24hrs on the tub and in the books I've read and it's after then that the oddness begins! It could just be because the mixing tank's still new or I'm doing something really dumb which I'm not noticing!

 

[xxBarneyxx]

Just think it could be worse...... You could get a crack in your tank....... actually nm... (sorry )


I did just dig this up which may be of use:
Always add the salt mix to the water, not the other way around. Adding water to the salt mix briefly creates a very highly concentrated solution which can lead to precipitation of some ingredients.

Not sure if thats how you did it in this case but something to be aware of I guess.

Edit: nm read your first post again and saw you added the salt to the water and not the other way around. Thats that theory out the window.

 

[idlefingers]

Just think it could be worse...... You could get a crack in your tank....... actually nm... (sorry )

Mean. Plain mean.

I did just dig this up which may be of use:
Always add the salt mix to the water, not the other way around. Adding water to the salt mix briefly creates a very highly concentrated solution which can lead to precipitation of some ingredients.

Not sure if thats how you did it in this case but something to be aware of I guess.

I've been adding the salt to the water but cheers anyway.

 

[SkiFletch]

Shouldn't seem strange at all. Seachem makes a more high-end salt, meaning it will have a LOT of calcium and alkalinity. When the salt is first mixing, there can be supersaturation areas of calcium and alkalinity (carbonate) especially in those mixes that try to achieve high calc/alk. In these supersaturation areas, precipitates (white stuff) can and do form. Remember, Seachem is trying to "go to the edge" and sometimes when you do that you go a little bit over. As they said though, it's nothing to worry about.

 

[idlefingers]

makes sense.. cheers for that ski!