Success with tap water

[ben_t]

Hi,

I'm wondering about keeping fish but not sure if my local tap water would be up to scratch. I noticed some forum members are in the same area as me so wondered about peoples first hand experiences? I live near Eastleigh and my water comes from an underground source at Twyford. The water flows under chalk hills and is known to be hard.

I've just downloaded the report from Southern Water and they say the hardness is 16 dGH which is exactly what I used to measure when I kept fish years ago, I have an old spreadsheet with some of these values noted down. Slightly concerning is that the Southern Water report lists nitrates as 35 mg/l which is apparently roughly equivalent to ppm. I've read that nitrates should be kept as low as possible with 5-10 ppm being a good benchmark. Have I read these nitrate levels correct? I'm thinking with the nitrates and hardness that tap water might not be sufficient. I don't really want the expense and hassle of RO water which is also quite wasteful.

There is a lot of conflicting information online, some say that in hard water you can only keep livebearers or African cichlids while others say water parameters don't matter as long as you keep on top of maintenance. It would be great to hear some first hand experience from those with similar water parameters, which fish and plants would work, whether a low tech tank with no co2 would work, whether these background nitrates from the tap are correct?

Thanks

 

[hypnogogia]

If you need to soften your water, you can always cut it with rain water.

 

[AverageWhiteBloke]

you can always cut it with rain water.

I've moved solely to rain water in my tank. It's in abundance at the moment and where I live they are currently changing the source we get our water from so lots of blending from underground sources and a lot of work getting done on the pipeline which I would imagine means them flushing it with whatever quite often. The only tapwater I add is when I boil a kettle full up to bring my rain water up to temperature on water change day.

Southern Water report lists nitrates as 35 mg/l

Quite decent of your water company to throw in some free fertiliser, I have to buy some and add it. If you live in an area without any factories spewing stuff out nearby try rain water cut say 50/50 with your tap. You can buy a kit to cut into your down pipe to divert water into a barrel. Having said that people still have a lot of success with hard water and plants. Get a Trace fertiliser that works well in hard water.

 

[dw1305]

Hi all,
Welcome to UKAPS. A lot of our members have hard water and <"keep successful tanks">. Have a look for tanks from @Guest, @Zeus. and @Geoffrey Rea.

and they say the hardness is 16 dGH which is exactly what I used to measure when I kept fish years ago

Yes, that is <"about the figure you get"> when your water is fully saturated with calcium (Ca++) and bicarbonate (HCO3-) ions. The carbonate hardness (dKH) will also be about 16 degrees, because nearly all the dGH and dKH <"comes from the chalk (CaCO3)"> aquifer.

Slightly concerning is that the Southern Water report lists nitrates as 35 mg/l which is apparently roughly equivalent to ppm.

Yes, same again, pretty <"common nitrate values"> for a lot of us in the South and East of the UK and yes again "ppm" and "mg/L" are equivalent measurements and interchangeable.

Quite decent of your water company to throw in some free fertiliser,

That is one of the great things about planted tanks, <"nitrate levels go down"> rather than up. Have a look at the <"Leaf colour chart">.

If you need to soften your water, you can always cut it with rain water.

I've moved solely to rain water in my tank.

I'm a <"rain-water user">, as well.

cheers Darrel

 

[sparkyweasel]

I've read that nitrates should be kept as low as possible with 5-10 ppm being a good benchmark. Have I read these nitrate levels correct?

You've read that right, - it's the people that insist on writing it that are wrong. 🙂
Often the source is some-one trying to sell you some magic potion they claim removes nitrate. Nitrate is an essential plant food, we don't want to remove it.

 

[jacquieb]

Liquid chalk here in East Sussex: easy keepers Golden barb, Harlequins, Lemon tetras, neon dwarf Rainbowfish, cory (I have pygmy, hasbero and a synodontis that's at least a decade old), most danios, mountain minnows. Platys and swordtails do too well and the population explosion can become a problem quite quickly. Cherry shrimp also breed and breed. I have kept crystal shrimp too and they do sometimes breed but not as prolific. Less successful in my experience are neons, gouramis and tetras other than lemons.

Plant wise (low tech) - cryptocoryne, anubius and bucephalandra on wood, hygrophila species, val (if you aren't using liquid carbon) and helanthium tenellum for the foreground. I've found bigger echinodorus tend to sulk and java fern never looks quite as good as I'd like.

The only way to truly know what will work in your tank is to try it and see, and that's half the fun. Enjoy!

 

[Conort2]

Cutting with rainwater is a good idea if you feel your water is too hard. However there are plenty of species that will thrive in that type of water. Rainbow fish are an excellent choice, most danio and barb species will also thrive, hillstream loaches, gobies.

Are there Any particular fish you really like the look of? if so let’s us know and we can advise on whether these would be suitable.

cheers

Conor

 

[dw1305]

Hi all,

Often the source is some-one trying to sell you some magic potion they claim removes nitrate.

Southern Water report lists nitrates as 35 mg/l which is apparently roughly equivalent to ppm. I've read that nitrates should be kept as low as possible with 5-10 ppm being a good benchmark. Have I read these nitrate levels correct?

It is back to whether nitrate (NO3-) is the <"smoking gun of nitrification">, and indicates that <"you've had high levels of ammonia (NH3) and nitrite (NO2-)">, or whether what we measure has always been the nitrate ion (the situation in tap water).

We don't know at what level nitrate becomes <"toxic to our fish">, but there is work on <"Zebra Danio (Danio rerio)">, because of its use as a model organism in universities.

cheers Darrel

 

[AverageWhiteBloke]

I've read that nitrates should be kept as low as possible with 5-10 ppm being a good benchmark.

With planted aquariums running out of nitrates as well as all the other elements is avoided at all costs with it being detrimental to plants. If you look in certain parts of the forum you can see how many people with deficiency issues are searching for what's missing so in your case with your tapwater it just means nitrate is going to be the least likely.
Below is a graph of accumulation courtesy of Rotala to show how effective plants are at stripping out nitrate. The settings are your suspected 35mgl tapwater in a low energy well planted tank changing 40% of the water every two weeks. It makes an assumption that the plants are consuming 1ppm per day which isn't an unrealistic figure. The plants could consume upto 3ppm per day if you throw more light or some co2 at it. As you can see over the course of the year there are times when you are bottoming out. Cut 50/50 and you certainly are unless you start changing weekly to counter it.

If you do throw co2 and light in there increasing plant uptake and cut 50/50 chances are you probably will need to add some additional nitrate.

 

[mort]

From a fish perspective with hard water, my local water is like liquid rock as well, it's not such a big issue nowadays. It is great for livebearers and the normal hard water lovers but most species have been bred in captivity for so long now that they are really adaptable. If you go to your lfs just ask what they keep their fish in. At my lfs the only fish they don't keep in our hard local tap water is discus and wild caught south american species, everything else including captive bred apistogramma, pencilfish etc is just tap water.
It is true to say that many fish are happier in softer more acidic water and you may stifle some breeding but it's not necessarily a problem. If you can mix your tap with rainwater or ro it's even easier.

 

[Aqua sobriquet]

One of the worst aspects of hard water is what it does to the tank and equipment. I now use mostly rain water and that’s fine but years ago I was forever trying to scrape limescale off everything.

 

[ben_t]

Apologies for not replying sooner, it’s been a busy week but I have been reading the replies and some of the further reading.
Rain water could be an option although a slightly scary one. We have a water butt for the garden but I’m not sure how clean the water is. There’s always slugs in there and the water doesn’t look totally clear and pure. Last summer it ran dry for quite a few weeks which could also be a problem.
I know plants need Nitrogen but I’ve always heard that high nitrates are bad for the fish. Water changes are usually recommended to dilute these waste products so I was a bit concerned that my tap water apparently has a fair amount of nitrates. Maybe in a planted tank this will be less of an issue though as the plants will help balance things out.
Regarding the tank I was thinking of something in the 10-20 gallon range, low tech with easy plants. There are quite a few fish I like the look of but haven’t really settled on anything. I wouldn’t want to stock too heavily and would like to keep things in a theme like Asian, amazononian, or something like that. Not a strict biotope. I quite like bettas, cherry shrimp, harlequins, sparkling gourami, corys, dwarf cichlids. I need to choose a theme and then pick something that will be happy in hard water and my size of tank.

 

[Karmicnull]

Like many people here I'm running in super hard south UK water (East Anglia for me). Low tech. I did a trawl of the internet and came up with the (not remotely exhaustive) set of fish below who all are ok in >=268ppm water (note that the internet inevitably disagrees with itself on all these figures. so these must be taken as estimates). Although as folks have said above, this may be conservative given how much stock is now bred in captivity and may have some degree of genetic adaptation. Also worth noting that running soft fish in hard water is less of an issue than the reverse.

Name	Latin Name	size (cm)	Low Temp	High Temp	PH	Hardness
Rasbora Vulcanus	Rasbora Vulcanus	4​	23​	26​	6.4-7.5	26-267
Emerald Dwarf Rasbora	Celestichthys erythromicron	2​	20.0​	24​	7.0-8.0	215-357
Red Dwarf Rasbora	Microrasbora rubescens	3​	20.0​	24​	6.0-8	54-268
Firehead Tetra	Hemigrammus Bleheri	5​	23​	26​	5.5-7	36-268
X-Ray Tetra	Pristella maxillaris	4.5​	22​	28​	6-7.5	35-358
Cherry Barbs	Puntius titteya	4​	20.0​	27​	6-8.0	36-357
Platy		7.5​	20.0​	25​	7-8.2	179-537
Bronze Cory	Corydoras aeneus	7.5​	21.0​	27​	6-8.0	36-268
Albino Cory		7.0​	22.0​	26​	6-8.0	35-447
panda cory	Corydoras panda	4.0​	20.0​	25​	6-8.0	36-358
Gold Cory	Corydoras melanotaenia	6.0​	20.0​	23​	6-7.2	36-268
Julii Cory		5.0​	23.0​	26​	6-7.8	36-447
Emerald Green Cory	Corydoras splendens	9.0​	20.0​	27​	5.8-8	36-268
Pygmy Cory	Corydoras pygmaeus	3.0​	22.0​	26​	6.4-7.4	36-268
Schwartz's Cory	Corydoras schwartzi	7.0​	22.0​	24​	6-7.5	18-268
Venezuelan Black Cory	Corydoras Schultzei	7.5​	22.0​	28​	6-8.0	36-268
Orange cory		7.0​			6-7.5	40-289
Bulldog Plec	Chaetostoma sp.	12.0​	20.0​	23​	6.8-7.8	144-447
Bristlenose Catfish	Ancistrus	12.0​	21.0​	25​	5.5-7.5	18-268
Inle Loach	Petruichthys brevis	6.0​	18.0​	24​	6-8.0	54-268
Siamese Flying Fox	Crossocheilus atrilimes	7.0​	20.0​	26​	6-7.5	18-268
Zebra Danio	Brachydanio rerio	5.0​	18.0​	25​	6-8.0	90-357
Celestial Pearl Danio (Galaxy Rasbora)	Celestichthys margaritatus	2.0​	20.0​	26​	6.5-7.5	90-268
Celebes Rainbowfish	Marosatherina ladigesi	8.0​	22.0​	28​	7-8.0	179-386
Neon Blue-eye	Pseudomugil cyanodorsalis	3.5​	21.0​	31​	7-8.5	179-447
Black Molly	Poecilia Sphenops	10.0​	21.0​	28​	7.5-8.5	179-447
Sailfin Molly	Poecilia latipinna	12.5​	21.0​	26​	7-8.5	269-626
Saffron Molly	Poecilia Sphenops	12.5​	21.0​	26​	7-8.5	269-626
Dwarf Gourami	Trichogaster lalius	7.5​	22.0​	28​	6-8.0	90-318
Pearl Gourami		12.0​	24.0​	30​	5.5-8	36-537
Thick Lipped Gourami	Trichogaster labiosa	10.0​	22.0​	27​	6-7.5	90-268
Honey Gourami	Trichogaster Chuna	5.5​	22.0​	27​	6-7.5	36-268
Golden Pencilfish	Nannostomus beckfordi	3.5​	21.0​	27​	5-8.0	18-268
Wrestling Halfbeak	Dermogenys pusilla	7.0​	24.0​	28​	6.5-8	179 - 358

Asian Rummynose	Sawbwa resplendens	3.5​	18.0​	22​	6-8.0	54-268
Daisy's Ricefish	Oryzias woworae	3.0​	23​	27​	6-7.5	90-268
Indian Glassfish	Parambassis ranga	8.0​	20.0​	30​	6.5 - 8.5	142-358

Cheers,

Simon

 

[dw1305]

Hi all,

Water changes are usually recommended to dilute these waste products so I was a bit concerned that my tap water apparently has a fair amount of nitrates. Maybe in a planted tank this will be less of an issue though as the plants will help balance things out.

That is it, plants actually do a lot more than just balance it out, they really are the <"gift that keeps on giving">.

Most forums, web sites and LFS massively under estimate just how effective plants are in removing all forms of fixed nitrogen. I've been a long term fish-keeper, but I have <"slightly different perspective"> because it is something I've had an interest in via my <"day job">.

Rain water could be an option although a slightly scary one. We have a water butt for the garden but I’m not sure how clean the water is. There’s always slugs in there and the water doesn’t look totally clear and pure.

You can use a <"bioassay technique"> to monitor your water quality, but you do need quite a lot of water storage to tide you over the summer period.

A lot of people on forums etc are wary of rainwater, but against that a lot of really <"experienced aquarists"> use it. Have a look at this thread on <"PlanetCatfish">, the OP "MarcW" lives near you.

cheers Darrel

 

[aec34]

I am absolutely no expert but I use primarily rainwater for a pair of little tanks, but with a combined volume of only 35 litres (because I was worried about high ph of my tap). I’ve got one butt linked off another, and draw from the second so any bits settle out in the first - I read this somewhere on here. I’m sure I’ve had a few random beasties get in (water fleas, a few tiny worms) from it, but so far it’s been very straightforward and the plants and shrimp are happy - can’t speak for fish. I keep a couple of 5 litre plastic containers filled with it in the house so it’s not too cold.

EDIT: looks like a bunch of copepods have made their way in.. 😳 *reaches for cleaning kit