[Sounduser]

Hi. I've got a couple of questions about chemicals I use for my fish tank.

I use calcium hydroxide to maintain Ph in my aquarium. It is mixed with fresh water in a top up tank, that is added to the main tank to counter evaporation.

1) Is there any reason why I cant add a very small amount of alcohol to the mix? <25ml in 10 litres?

Also. I add calcium to the tank with a peristaltic pump in the form of calcium chloride. And Sodium carbonate with another pump to maintain Kh

2) Is there any reason I cant add some magnesium chloride and potassium chloride in the same bottle as the calcium chloride? My thinking is they wont react because they're all chlorides?

Cheers guys. Thought I'd double check before any weird reactions happen. 

[curiouscat]

1) Is there any reason why I cant add a very small amount of alcohol to the mix? <25ml in 10 litres?

Sounds ok. I cannot see any downsides.

[billnotgatez]

@Sounduser
Will the ethanol effect the fish
are you asking more of a biology question than chemistry

Chemistry wise I think you are correct about the chlorides you mentioned
Again this could be a biology question

Do you have insight to the biology

[Sounduser]

Yeah I should have been more clear. I'm adding the vodka now. Probably .5ml per day by hand. Was thinking this could be an easy way to automate it. (Tank is 700 litres including filters)

small amounts of carbon sources are used to support bacteria populations in marine aquariums. People use vinegar, sugar or vodka. The extra bacteria use the carbon in some kind of biological process that consumes nitrates and phosphates.

I've read that calcium hydroxide doesn't dissolve in alcohol , but mixes with the water. So as long as I didn't hit maximum concentrations. I was thinking it should be fine??

Thanks guys

[Montegue]

There is no need of artificial source of carbon in water. Carbon is there naturally. The fish eat and poop. Dead bacteria is a source of carbon itself. The fish breath out carbon dioxide and the air in the water contain carbon dioxide. Carbon dioxide dissolves in water and plays important role in pH level. Calcium is very rich in marine aquarium, so calcium bicarbonate exists abundantly. That's one source of carbon, and there are many more

Adding alcohol, sugar or vinegar is over doing it.

Chloride in natural sea water is just right. The artificial sea water is made to match the concentration, and naturally stays stable for at least 6 month. After 6 months, it will be slightly brownish. This color is mostly the effect of carbon build up. This is why every 6 month the water is replaced to re-establish balance in trace elements. Adding alcohol, sugar or vinegar will cause the quality to deteriorate faster.

[Sounduser]

carbon dosing helps maintain large colonies of bacteria in a closed system. I would have thought that there would be massive amounts of carbon in the water, but it seems to be the wrong kind. Dissolved organic carbons constantly precipitate out of the water. Resulting in insoluble crud in the filters.

Never the less, probiotic reefs seem to be the most colourful with the cleanest water quality.

[Sounduser]

Nobody see a problem with me mixing the three chlorides??

[bradvincent]

I am a fellow reef aquarist here.  Can you please define "problem"?

If you are asking whether 3 chlorides will initiate cold fusion killing everyone within 1000 miles, the answer is "no".

If you are asking whether magnesium chloride and potassium chloride will decrease the amount of calcium chloride that can dissolve in tap water, the answer is probably "yes", but the best way is to experiment.  It is very easy to measure how much of something dissolves.

If you are asking about whether mixing the 3 chlorides together will make it harder to maintain your aquarium, the answer is probably "yes".  What do you do when the magnesium is high and calcium is low?  You have to change your formula.  Much easier just to add calcium chloride periodically and magnesium only when magnesium measures low.

Why are you adding potassium chloride?

You do realize these 4 chemicals (calcium hydroxide, calcium chloride, sodium carbonate, magnesium chloride and potassium chloride) will shift your ionic balance to favor chloride over sodium over time.    Calcium hydroxide will not shift the balance, and calcium chloride and sodium carbonate in appropriate doses to maintain calcium and alkalinity won't either.  But the other 2 add chloride and not sodium.  This is fine if you are adding balanced sodium another way, or just not adding much.

[bradvincent]

There is no need of artificial source of carbon in water. Carbon is there naturally. The fish eat and poop. Dead bacteria is a source of carbon itself. The fish breath out carbon dioxide and the air in the water contain carbon dioxide. Carbon dioxide dissolves in water and plays important role in pH level. Calcium is very rich in marine aquarium, so calcium bicarbonate exists abundantly. That's one source of carbon, and there are many more

Adding alcohol, sugar or vinegar is over doing it.

Chloride in natural sea water is just right. The artificial sea water is made to match the concentration, and naturally stays stable for at least 6 month. After 6 months, it will be slightly brownish. This color is mostly the effect of carbon build up. This is why every 6 month the water is replaced to re-establish balance in trace elements. Adding alcohol, sugar or vinegar will cause the quality to deteriorate faster.

Just wanted to comment on Montegue's post, for those who don't keep reefs.  The 6 most abundant elements in life are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur.  Suppose you have a semi-closed system where life (bacteria and algae) will rapidly consume these until one of these is depleted and limits growth.  Oxygen is abundant in tank water from dissolved atmosphere.  Free Nitrogen and Carbon (as CO2) are also present from dissolved atmosphere, but (mostly) not usable in this form.  Sulfur is assumed to be present in excess, but not harmful.  The concern is Carbon becomes the limiting element, leading to an accumulation of Nitrogen (as Nitrate) and Phosphorus (as Phosphate) both of which are harmful in excess.  By adding Carbon, bacteria can consume Nitrate and Phosphate and then be removed from the system.  This is proven and works well in a large number of reef tanks.  A Nitrate and Phosphate rich, Carbon poor environment favors algae growth and a Carbon rich, Nitrate and Phosphate poor environment favors bacteria.  Bacteria is easily removed, algae looks bad, is hard to remove, and can kill what it grows on.

BTW - fish poop does not add Carbon to the system, as the fish are part of the system.  Fish food does add carbon.

[Arkcon]

BTW - fish poop does not add Carbon to the system, as the fish are part of the system.  Fish food does add carbon.

I don't see how there really is a difference in the carbon added via fish food or fish poop.  Probably, the rest of you missive is valid based on your aquarium experiences.  But most of this thread has nothing to do with chemistry that high schoolers, university students, or industry professionals really need.  And some of it would be downright wrong if applied in those cases without heavy caveats.

[curiouscat]

I don't see how there really is a difference in the carbon added via fish food or fish poop.

Hmm....there might be a difference in this way: Say 10% of all fish is  C. Say on Day0 we have 10 kg of total fish matter in the tank. Now either due to fish growth or reproduction the total fish matter on Day60 is 20kg.

The 1kg difference in C has to be externally provided (food etc.). It cannot come  via fish poop.

Maybe, that's what he is signalling. Fish poop would be fine, if only you were shoveling it in from another tank.

This is assuming fish cannot convert inorganic C (dissolved carbonates etc.) into organic C.