Minerals for osmosis water?

[KrisA]

Anyone useing minerals to mix up with there osmosis water, to reach the 200-300 uS?
Haven't used anything so far, besides mixing with tap water, I'm thinking about useing ''Preis discus Mineral''

Preis discus Mineral

[Bas Pels]

Firstly, vitually all South American waters are below 100 micro Siemens.

If I were to use 300 - I'd open my tap. This gives 350

Secondly, the water from the tap consists of chlorine, (bi)carbonate, sodium, magnesium and calcium. As magnesiumbicarbonate does not dissolve in water - and calcium bicarbonatre only dissolves very slowly - it is much better to get the minerals in 2 batches: MgCl2, CaCl2 and NaHCO3. These can be dissolved separately and then mixed

[MatsP]

Firstly, vitually all South American waters are below 100 micro Siemens.

If I were to use 300 - I'd open my tap. This gives 350

That clearly depends on where you live. My tap-water is around 320 ppm according to my TDS meter [as measured yesterday - earlier this year it was a little lower, 300 ppm]. Since you typically multiply by 1.6 to get the uS/cm value, the value in my tapwater is somewhere around 500, give or take a couple of tens.

Secondly, the water from the tap consists of chlorine, (bi)carbonate, sodium, magnesium and calcium. As magnesiumbicarbonate does not dissolve in water - and calcium bicarbonatre only dissolves very slowly - it is much better to get the minerals in 2 batches: MgCl2, CaCl2 and NaHCO3. These can be dissolved separately and then mixed

The powder in these type of tubs tend to be some mix of the chemicals you list, but typically more sulphate than chloride - which is a good thing. Of course, in typical fishkeeping hobby style, the actual content is generally not given in a sane way, you have to read the chemical safety data sheet or something like that to figure out what it actually contains.

I have been using a product from Tropic Marin, called TMC Re-Mineral Tropic, and I'm happy with that. But there are several other products on the market, and the content is pretty much similar from what I have been able to determine.

I run my tanks around 100-150 ppm, so around 160-240 uS/cm.

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Mats

[Bas Pels]

Firstly, vitually all South American waters are below 100 micro Siemens.

If I were to use 300 - I'd open my tap. This gives 350

That clearly depends on where you live. My tap-water is around 320 ppm according to my TDS meter [as measured yesterday - earlier this year it was a little lower, 300 ppm]. Since you typically multiply by 1.6 to get the uS/cm value, the value in my tapwater is somewhere around 500, give or take a couple of tens.

Mats

Obviously. I'm kind of blessed with soft water - so I keep hard water fish

[KrisA]

My tapwater is around 800 uS, so is pretty hard

I cant find the ''TMC Re-Mineral Tropic'' in a single danish aquarium shop, so i think it's got to be the ''Preis discus Mineral'', if I'm getting it

[ceh]

RO water have wery low uS why higher level ?

[Bas Pels]

You could mix tap water with osmosis water in order to get the microsiemens you want.

Obviously, you would need to have water which is pure enough - that is, quite free of nitrates and so on. But assume 10 mg/l nitrates. You aim @ 200 microsiemens - thus 1/4th of the water you use comes from the tap, the rest is osmosis water

Well, in that case the nitrates are also diluted bij a factor 4 - to 2.5 mg/l. Most likely acceptable

[MatsP]

Yes, mixing tap-water or even slightly better, RO waste-water which you'd have plenty of, since the RO unit produces some 75% or so waste, and 25% or so "pure" water.

But various companies make products of this kind, that contain a supposedly good mix of minerals.

Using only RO water wouldn't work, as it has no KH, which is needed to keep the pH at a stable level, which makes because the beneficial bacteria that we rely on in the filter to destroy ammonia and nitrite aren't going to work at very low pH - and although some fish live in pH 4 in nature, they are also in rivers that have a lot more water, so ammonia and nitrite are much more diluted, and there is propoprtionally a fair bit more bacteria available in the river than in our filters.

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Mats

[Bas Pels]

Yes, mixing tap-water or even slightly better, RO waste-water which you'd have plenty of, since the RO unit produces some 75% or so waste, and 25% or so "pure" water.

The problem is, this waste-water is concentrated. Or better put, it contains the minerals which were taken form the RO water

Starting @ 800 microsiemens, the waste water will be around 1000 microsiemens

So you would need to use less - but than, this water is used anyway

[MatsP]

Yes, mixing tap-water or even slightly better, RO waste-water which you'd have plenty of, since the RO unit produces some 75% or so waste, and 25% or so "pure" water.

The problem is, this waste-water is concentrated. Or better put, it contains the minerals which were taken form the RO water

Starting @ 800 microsiemens, the waste water will be around 1000 microsiemens

So you would need to use less - but than, this water is used anyway

Yes, so you use a bit less, but at least it's dechlorinated and has had whatever else the particle and carbon filters pick up removed. Which certainly can't be a bad thing. It may still contain a bit of the stuff you don't want (such as nitrate) from the tap-water. And I have to admit I'm not following my own advice here - mainly because I would have problems mixing the water. So I use plain RO water and mix in powder as I fill up the tank.

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Mats

[Bas Pels]

I keep forgetting people have chlorinared water

That is an issue, right

[perclown]

Anyone familiar with the balling method, a 2 part recipe for replenishing Calcium and KH to reef aquariums. Might work if using very little for reconstituting minerals lost by DO.

[racoll]

The problem is, this waste-water is concentrated. Or better put, it contains the minerals which were taken form the RO water

You would think it would be, but when I tested it, it was pretty much identical in TDS to the input (tap) water.

[perclown]

Does anyone knows what are the main minerals needed to "reconstitute" RO water, DI removes Ca and Mg.
How do sensitive catfish react to RO vs DI vs tap water? Is there a "catfish happymeter" besides EC or pH?

[Janne]

Firstly, vitually all South American waters are below 100 micro Siemens.

Not completely true, in general for the lowland amazonas but absolutely not for the whole South America.

Obviously, you would need to have water which is pure enough - that is, quite free of nitrates and so on. But assume 10 mg/l nitrates. You aim @ 200 microsiemens - thus 1/4th of the water you use comes from the tap, the rest is osmosis water
Well, in that case the nitrates are also diluted bij a factor 4 - to 2.5 mg/l. Most likely acceptable

Nitrates is a problem, fool many people to think the hardness is fine... above example works well if changing 100% of water each time but most people dont.

You would think it would be, but when I tested it, it was pretty much identical in TDS to the input (tap) water.

Bad RO or bad test's, the waste water from a good RO unit should have far higher TDS/µS than origin input water.

Janne

[racoll]

You would think it would be, but when I tested it, it was pretty much identical in TDS to the input (tap) water.

Bad RO or bad test's, the waste water from a good RO unit should have far higher TDS/µS than origin input water.

Well, the RO appeared to be working perfectly, and the EC meter was good quality and frequently calibrated.

Still, would be very easy for someone to verify this on their own system?

[Bas Pels]

Racoll,

If I start with 100 liters of water,@ 500 ppm, the RO unit produces 20 liters @ 0 ppm, and the stuff which was dissolved will not stay in the RO unit.

Regardless what tests say, the restwater, that is, the 80 liters, wiull have to contain this stuff as well, resulting in something like 600 ppm

The alternative would be that the stuff would disappear - and that just won't happen.

Put in other terms, the balanse of mass - that is, if mass does not collect on a point, than every gram coming must also be going, is the most important law of chemical technology. The RO water leaves mass, which will, therefore, have to leave through the other exit - the waste water

[racoll]

Well, it is struck me as odd at the time too, for the reasons you describe above.

and the stuff which was dissolved will not stay in the RO unit.

Is is not possible, however, that the rate of release is slower than the rate of accumulation, i.e. the minerals get stuck on the membrane? After all, is this not why people are supposed to regularly "back flush" their membranes?

As I say, would be easy for someone to corroborate this ...

[Bas Pels]

I have no personal experience with RO, I'm just a fish keeper who graduated in chemistry, and as I hate waterprepping, I keep fish I don't need an RO unit for

I think the back flush might be for the incidential accumilation, but this will be small scale. I don't how often this is needed, but if it requires 1 liter to back flush for every 1000 liters produced - it is a very small amount, and most likely not able to remouve much.

That is, the little it can remouve is very impotant, but accumulation will still be a very small fraction indeed

[MatsP]

If any significant amount of minerals got stuck in the membrane, the membrane would stop working [or work less well] quite quickly. Just look at the inside of your kettle in a hard water area... That's from a few liters being boiled now and again, not from hundreds of liters...

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Mats