Soft water

Hi, I've been searching for the thread on rocks but can't find it so apologies for the question which I know is answered elsewhere.
I have very soft water so my pH is 6.4 and my gh is 3. I am looking to put granite based fossil bookends in as I believe the granite will leach carbonate and help increase the gh.
Q''s - a/ am I correct in thinking this and b/ anyone with any thoughts on why this would be bad to do?

Thanks in advance for your help,

Granite won't leach carbonate as it is an inert, igneous rock. However, limestone is made of calcium carbonate and with your acidic pH will leach some carbonate, which will increase KH and calcium which will increase GH. Shells and coral, also made of calcium carbonate, will do the same.
You would find that aragonite is better as that also contains magnesium, another component of GH. But neither will increase GH and KH by very much, not enough to make the water hard or even moderately hard.

However, your water is perfect for soft water fish. I would leave well alone and get those fish which like soft water and acidic pH. We have other members who have even lower GH.

Thank you. I have some aragonite sputnik's as luck would have it. Will give it some thought.

Granite is one of the safest rocks to add to an aquarium.

You would find that aragonite is better as that also contains magnesium,

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Actually aragonite is 90 to 95% calcium. Dolomite is a much better choice because it is about 50% calcium with remainder being magnesium.

However, limestone is made of calcium carbonate and with your acidic pH will leach some carbonate, which will increase KH and calcium which will increase GH.

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Adding limestone, aragonite, or dolomite to an aquarium at the PH you list will only add about 1 to 2 degrees of hardness to your aquarium. The affect of Calcium and magnesium carbonate on hardness is strongly affected by PH. At a PH of 7 or higher these carbonates will not dissolved in water and therefore will have no affect on PH or GH. However in acidic well water the effect is very strong with some well production water that is considered very hard. So your water would have to be at a PH of 6 or less to see any significant effect on PH. But there is a benefit to adding it to PH neutral tank.

Calcium magnesium carbonate would stabilize your PH at 7. It will not push it above hat.level. It would take a lot of CO2 injected into an aquarium to see the PH drop and GH increase. .So for a PH neutral tank add calcium magnesium carbonate would fix the PH at 7 and at the same time keep the hardness soft enough for most soft water fish. A pice of dolomite the size of a marble would be enough for 20 gallon tank and it would take years for it to dissolve away. It would also insure your water always has enough calcium and magnesium in the water for plants and shrimp.

StevenF said:

Actually aragonite is 90 to 95% calcium. Dolomite is a much better choice because it is about 50% calcium with remainder being magnesium.

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I have got the two confused in my memory I have just checked and you are quite right

Aragonite is CaCO3 with some impurities, dolomite is CaMg(CO3)2 (sorry, I don't know how make the numbers as subscripts)

OK, at the moment I am using liquid CO2, which is supposedly not CO2? New to the CO2 thing so not really sure about it yet. And have a planted aquarium, with a soil type substrate and sand on top. Some plants are not dug in to the substrate so am adding a smaller amount of fertiliser than would be required if the tank were a few months down the line.
So far I've not seen any change in pH. Is this because the liquid CO2 is not really CO2? It's a 90L tank and I add approx. 1.6mls (allowing for substrate and rock water displacement).

Sadly I do not have any dolomite in my rock collection.

Seachem Flourish Excel is glutaraldehyde, other brands of liquid carbon may also contain this, or something similar. Plants can extract carbon from these chemicals.

A lot of people won't use these liquid CO2 products. Google glutaraldehyde and you'll see why.

the aldehyde part of that has me squirming in my seat already. Sounding scarily close to formaldehyde... off to Google it.

Good grief. I thought it slightly odd that my neutro CO2 didn't have an ingredient label on it and now I know why. Can't find a data sheet for it anywhere, only one comment on amazon saying it is, exactly what you state, diluted glutaraldehyde. I know it states this is an algicide but surely it is cytotoxic to fish also?

https://en.wikipedia.org/wiki/Glutaraldehyde

It is a sterilizing agent used on medical instruments. At very high does it will kill everything in the tank. At low doses it reportable can help plants without killing fish or shrimp.. but it will kill some plants at this dose. If you want to insure you always have enough CO2 in your water use an air stone. CO2 levels in air are currently 400ppm. I did a search and found CO2 levels in the great lakes is 400 to 500ppm. In a rain drop it can reach 1000ppm. I personally positioned may filter output spacebar about 1/2 above the water surface The water hits the surface song enough to pull air below the surface of the water and sounds like a fountan.(which I prefer over a the hum of a air pump.

What fertilizer are you using? Many fertilizers don't have all the nutrients plants need and some are frankly garbage (Tetra and API).

Hi
Sorry for jumping in I just wanted to share my experience with glutaraldehyde. Seachem Excel.

Health effects that may occur as a result of exposure to glutaraldehyde include but are not limited to the following:

• Throat and lung irritation.
• Asthma and difficulty breathing.
• Contact and/or allergic dermatitis.
• Nasal irritation.
• Sneezing.
• Wheezing.
• Burning eyes and conjunctivitis.

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I must have sensitive skin, I got some on my fingers once and had a bad rash for 6 or 7 days.

If you use this stuff please use it with caution, Do not get it on your skin, Do not overdose, Do not just add it to your tank dilute it in a bucket new water at water change time, there are places on the net that recommend double doses to kill algae this is bad advice.

I would also leave the water as is, there are some really cool fish that love soft water.

An airstone will not change CO2 in a properly set up tank. If at all it will decrease CO2 due to added water movement.

As already mentioned there is no additional CO2 in nature either and plants still grow

Edit: spelling correction

I've used cold sterilisers in theatre, it's a last resort and insturments are thoroughly rinsed with sterile saline before going near tissues. We also wear masks when pouring it. I'm not hugely keen about putting such a chemical in with fish and bought easy care plants so I will see how they go without the "CO2".

I'm using Flourish as a fertiliser, a general one.

Re. the hardness... I found mention that coral can help increase pH/GH and I have some ancient dead coral we inherited when my OH 's Mum died. I've boiled it, crushed some and put it in the second filter area to see if it helps. Will keep a close eye on the water parameters for the next few days to see how it goes.

I'm mainly worried about putting shrimp in there, and my hubby wants dwarf leopard catfish which as far as I can see would be a no no in such a soft watered tank.

As an aside... NickAU, love your tag line.

What fish do you mean by dwarf leopard catfish, Synodontis petricola?

Be warned that you can't keep anything small with that. And you'd need at last 4 of them.

I agree with others who have suggested you select fish species suited to your source water parameters. Believe me, this makes life very much simpler and easier. There will likely be times when an emergency water change is needed, and there are the regular weekly water changes which should be close to half the tank volume, and having to prepare water outside the aquarium is not as easy as some might think. And, the more you fuss with water chemistry, the more there is to go wrong; reactions in an aquarium can be significant, rapid and deadly.

Others have well covered the Excel/glutaraldehyde issue. Remember that every substance added to the tank water does get inside the fish. I know some will claim that Excel is "harmless," but this is pure nonsense. The fact that the fish "live" does not mean the substance is not somehow affecting them, and this is never good. Enough said from me.

CO2 as noted earlier in this thread is not usually an issue. If you are aiming for an aquatic garden, with mega light, daily fertilizing, then diffused CO2 is beneficial. But this too impacts fish. I have what I consider fairly well planted tanks with no bright light or CO2 addition in any form, and I use Flourish Comprehensive Supplement once a week. Photo below is illustrative.