Tricky tap water

[Sunnyspots]

I've tested my tap water and hunted for appropriate fish, but I'm having problems. My tap water parameters, as checked with the Tetra water test set, are:

GH 3
KH 1 or 2
pH somewhere between 7.5 and 8.0 (my water supplier quotes 7.4 to 8.8)

I have an 80l, 60cm long tank which is planted and has assorted wood, so about 60l working volume. I'd like to have peacock gudgeon gobies and a tetra (black widows appeal) but both require slightly acidic water and hardness above 5 dH. Are there any other fish that would better suit my water or will I need to alter the parameters myself?

 

[Byron]

First point is that the GH is the more important parameter, and at 3 dGH (assuming this is in degrees, not ppm) you have very soft water. While ranges for GH, pH, and temperature are always expected, most soft water fish species will be fine in any water that can be classed as soft or very soft, with very few exceptions. The gobies, Tateurndina ocellicauda, will have no issues here.

As for the pH, it is possible the water authority is adding something to raise the pH. This is common with soft water, as the lower pH can corrode pipes, etc. See if you can track this down; often these additives like soda ash will dissipate out fairly quickly. The pH will stabilize in an established aquarium and water changes thereafter will have little effect on the pH.

I would forget the Black Widow Tetras. They really need more space, with a decent-sized group or they can turn to fin nipping. There are however many suitable characins that would work, such as the Black Phantom, Red Phantom, etc; not the Serpae or Red Minor though, it is a notorious fin nipper and needs more space.

 

[Sunnyspots]

First point is that the GH is the more important parameter, and at 3 dGH (assuming this is in degrees, not ppm) you have very soft water. While ranges for GH, pH, and temperature are always expected, most soft water fish species will be fine in any water that can be classed as soft or very soft, with very few exceptions. The gobies, Tateurndina ocellicauda, will have no issues here.

As for the pH, it is possible the water authority is adding something to raise the pH. This is common with soft water, as the lower pH can corrode pipes, etc. See if you can track this down; often these additives like soda ash will dissipate out fairly quickly. The pH will stabilize in an established aquarium and water changes thereafter will have little effect on the pH.

I would forget the Black Widow Tetras. They really need more space, with a decent-sized group or they can turn to fin nipping. There are however many suitable characins that would work, such as the Black Phantom, Red Phantom, etc; not the Serpae or Red Minor though, it is a notorious fin nipper and needs more space.

I'll look them up!

 

[Sunnyspots]

I'll look them up!

First point is that the GH is the more important parameter, and at 3 dGH (assuming this is in degrees, not ppm) you have very soft water. While ranges for GH, pH, and temperature are always expected, most soft water fish species will be fine in any water that can be classed as soft or very soft, with very few exceptions. The gobies, Tateurndina ocellicauda, will have no issues here.

As for the pH, it is possible the water authority is adding something to raise the pH. This is common with soft water, as the lower pH can corrode pipes, etc. See if you can track this down; often these additives like soda ash will dissipate out fairly quickly. The pH will stabilize in an established aquarium and water changes thereafter will have little effect on the pH.

I would forget the Black Widow Tetras. They really need more space, with a decent-sized group or they can turn to fin nipping. There are however many suitable characins that would work, such as the Black Phantom, Red Phantom, etc; not the Serpae or Red Minor though, it is a notorious fin nipper and needs more space.

A number seem to require more tank length than I have, but the Glowlight and Pretty tetras look promising.

 

[Avel1896]

Hey there,
@Sunnyspots are you sure about GH3 KH1-2 and pH 7.5-8 ?? A rather high potential hydrogene isn't commonly seen with these GH and KH.
@Byron ?

 

[Byron]

Hey there,
@Sunnyspots are you sure about GH3 KH1-2 and pH 7.5-8 ?? A rather high potential hydrogene isn't commonly seen with these GH and KH.
@Byron ?

I mentioned this in my post #2, the OP needs to check with the water authority as thy may be adding something. I live in Vancouver and the source water is zero GH/KH with a pH of 7.0 to 7.2, but the pH is due to the addition of soda ash to raise pH (without affecting GH/KH).

 

[Avel1896]

pH of 7.0 to 7.2, but the pH is due to the addition of soda ash to raise pH (without affecting GH/KH).

Stupid question what's the difference between soda ash and baking soda ?

 

[Essjay]

Soda ash is sodium carbonate, Na2CO3. Baking soda is sodium bicarbonate, modern name sodium hydrogen carbonate, NaHCO3.

 

[Avel1896]

Okay... none affects GH/KF but add some sodium (salt?) to water, making it unsuitable for freshwater fishes ?

 

[Byron]

Okay... none affects GH/KF but add some sodium (salt?) to water, making it unsuitable for freshwater fishes ?

Sodium chloride, or common "salt" as in table salt or aquarium salt, is detrimental to freshwater fish (one or two possible exceptions). This salt should only be used to treat a specific problem, and then only if it is the safest and effective.

I have an article that explains the problems with salt, published here:

Salt FW Aq Art Hosking

 

[Avel1896]

Sodium chloride, or common "salt" as in table salt or aquarium salt, is detrimental to freshwater fish (one or two possible exceptions). This salt should only be used to treat a specific problem, and then only if it is the safest and effective.

I know this I mean for sodium chloride. Thanks for the link.

source water is zero GH/KH with a pH of 7.0 to 7.2, but the pH is due to the addition of soda ash to raise pH (without affecting GH/KH).

Does adding ash soda or baking soda to raise pH makes it unsuitable for freshwater fishes, like common salt does?

 

[Byron]

I know this I mean for sodium chloride. Thanks for the link.

Does adding ash soda or baking soda to raise pH makes it unsuitable for freshwater fishes, like common salt does?

Yes, in time. Baking soda is often suggested as a buffer for pH, but over time it does not "buffer" and it does negatively impact soft water fish.

Sodium carbonate (soda ash) is added to my source water and have been since 2001. I have not noticed any effect on the fish, and the pH in the tanks does remain fairly stable and well below 7. The soda ash seems to dissipate out fairly rapidly, I assume because the zero GH/KH provides no buffering.

 

[StevenF]

One thing to keep in mind is that for proper osmoticrecualtion fish need both sodium and potassium. To much or too little sodium can harm fish. Also too much or too little potassium can also harm fish. So for proper osmotic ballance fish need both and people need both.

Unfortunately the common aquarium belief is that any amount of sodium is bad. But people have no problem boosting KH with potassium bicarbonate and adding potassium nitrate with their plant fertilizer. End result is that some tanks are operating at or above the potassium limit for fish. IN other cases water softeners add sodium to tap water as they remove calcium and magnesium Often adding so much sodium to push an aquarium past the fish limit for sodium. Water utilities are tasked with producing water that is safe to drink. As part of that they need to control PH to avoid l unsafe corrosion of water pipes. They can use sodium or potassium carbonate, bicarbonates or any of a wide range of compounds that affect PH . Often the compound used is determined by price and the chemistry of the water. note what is safe for fish.

What is the correct balance for sodium and potassium in an aquarium? Unfortunately that depends on the fish and ithe enviroment it is typically found in. Additionally fish have the ability to adjust to changes that do occur seasonally. Sot the range of sodium to potassium fish can tolerate without any harm is quite large. And each species will be different.

 

[Avel1896]

Thanksss @Byron you're a font of science !

 

[Avel1896]

Hello @StevenF and thanks.
Is it safe to say that a freshwater pH7 GH6 KH4 is suitable to most fishes ?
Except of course for some very special fishes that need very special conditions, for example some wild Bettas pH4 GH0 KH0.