Holtrefeter's solution--is it homogenized?

[willowcat]

I use the Holtrefeter's solution with pure Mill-Q water for my Axolotls. To obtain enough volume I bought a 100 gallon per day R/O system and plan to store the water in barrels in the garage (elevated). A water tower so to speak of. This way I have the water on demand. My question is......Is the Holtrefeter's solution homogenized?

 

[Jennewt]

What do you mean by homogenized? In the case of salts (like Holtfreters) and a solution with water, I would define homogenized as "thoroughly mixed and dissolved". If this is what you mean, then yes.

 

[willowcat]

If the solution sits does it stay mixed, not separating, (like milk) or do the added salts separate and settle? If this occurs then it will have to be mix now and then. I do not want to have to rig mixing devises in my water tower so I am really hoping that it is considered a homogenize solution.
Oh....thank you for your return of my message and guidance. It looks like I found it (I think?).

 

[willowcat]

No. I found out the answer is no. I think it is the sodium bicarbonate that won't homogenize.

 

[auntiejude]

'Homogenized' is usually used to refer to a mixture of non-miscible liquids (such as water and fat in milk) where the mixture has been treated to ensure an even distribution of the mixed products. A solution does not fit this description, so the word 'homogenized' won't apply.

However, in answer to your question some solutions do 'settle' with a higher concentration at the bottom of a container and lower at the top since molecules heavier than water will sink - hence the advice on an average bottle of 'shake before use'. If you're maing solution in large quantities I would make sure you have a means to mix or stir it before use.

(Oh I knew that A-Level in chemistry would come is use some day!)

 

[willowcat]

Salts stay mixed and don't separate, correct, Auntie?

 

[oceanblue]

My understanding is standard Holtfreter's solution salts totally dissolve easily in a much smaller volume of water than the final solution used. Once dissolved they stay dissolved and do not precipitate out. Some modified versions of the formula including sulphate are unstable at high concentration and precipitate calcium sulphate.

If you are making the Holtfreter's from a liquid concentrate which contains visible undissolved crystals then shake it well so that the ratio of salts is unchanged.

 

[auntiejude]

Salts stay mixed and don't separate, correct, Auntie?

They usually stay dissolved, but you still need to mix the solution before use. Think of a gina and tonic tasting stronger at the bottom that the top - some solutions or mixtures can 'settle' and have different concentrations at different point in the liquid column.

As Oceanblue said, some salts may precipitate under certain conditions.

 

[willowcat]

The Milli-Q pure water drips into a 55 gallon plastic barrel. I measure out the ingredients.
The ingredients are granular and powder form. I take a bilge pump, with the capacity of
moving 1250 GPH. I have a hose on the end of the bilge pump. I submerge the pump into the water that is in the barrel. I take three 5 gallon buckets and fill the buckets up with the water. I then take the salts and add it to one bucket. I take the sodium bicarbonate and add it to another bucket. I mix with a pvc stick. I turn on the bilge pump that is in the barrel and then add the buckets to the swirling barrel of water. The bilge pump is allowed to run for along time, to make sure that the "solution" is thoroughly mixed. (I do not know why the letters are starting to type like this....sorry). For now, I store the mixed solution in buckets. I noticed that if the buckets are allowed to sit a while, then on the bottom of the bucket, a grainy feeling, residue is there. Now help me out some more, please.

Too Mix or Not Too Mix....that is the question.....just kidding....need help.....:crazy:

 

[oceanblue]

It sounds like you are making up the solution the right way. If it is only a very small residue I would be inclined to let it sit there, as it is not a true ingredient in the Holtfreter's but an impurity of some sort, not necessarily harmful. Holtfreter's salts should all dissolve fairly easily in concentrations several times the final concentration.