Reverse Osmosis

[JMcQueen]

I seem to be suffering from a high nitrate level from my tap water and it would seem the only real forward is via reverse osmosis. Im only planning on having a 120L tank so a relatively small one would suffice. Does anyone have one, are they easy to use and care for etc? I had heard that you cant allow the membrane to dry which might be a problem as I'd only be using it once a week for my weekly changes.

 

[Dinky Stig]

What is your resident country? In the UK the law states that nitrate levels in tap water must be below 50mg/l (ppm) nitrate is harmless until you get past 400mg/l, some more sensitive species 250mg/l

Reverse Osmosis water is nasty stuff when pure, and it has a mineral content of 0, so has no health benefits for fish, it is bad for them!
you could however do a mixture of 50% RO and 50% tap, but there shouldn't really be a need, as long as your nitrate level doesn't stray above 100 mg/l too often, you will be fine

Cheers,

 

[JMcQueen]

Im in the UK and the tap level is about 50. I did a 90% water change in my tank on Saturday and its already up to around the 110 mark on my test kit, it doesnt go any higher so I dont know the true level. The tank had just finished cycling as well so its not as if there was organic material to decompose in the tank etc.

I guess the RO isnt my solution after all.

 

[Dinky Stig]

Which test kit are you using? Chances are it's the test kit that's not doing its job, personally, I wouldn't even bother testing for nitrate, the quality of nitrate test kits is awful these days and they're not really very accurate, there are Salifert test kits, which have the re-agents kept seperate, which increases the reliability and validity of the results but they're still not perfect.

 

[JMcQueen]

its a nutrafin one. You could be right though as like I said, even the tap water seems to be recording high levels.

 

[Dinky Stig]

If you know who your water supplier is you can go onto their website where it will give you a breakdown of the water content including the nitrate levels, these are more reliable than a nitrate hobby test kit.

 

[JMcQueen]

Got this from the Anglia Water site:

Nitrate The high productivity of the Anglian region’s arable farming gives rise to high concentrations of nitrate in rivers and some groundwaters. Nitrate concentrations in our source waters have continued to increase over recent years. Where necessary, we operate and will continue to invest in a combination of nitrate removal plants and blending schemes to reduce these high levels of nitrate to below the 50 milligramme per litre standard. At sites where the concentration of nitrate is reduced by treatment or blending, the concentration of nitrate is continuously monitored.

During the period January 2009 to December 2009, 9 samples were taken for nitrate in the supply zone, all of which complied with the regulatory standard of 50 milligrammes per litre. The average value for nitrate in this supply zone during this period was 31.4 milligrammes per litre.

So while the test kit is over reading, its not a million miles away.

 

[Dinky Stig]

You're pretty safe in that case, it's nothing to worry about

 

[JMcQueen]

You're pretty safe in that case, it's nothing to worry about

The tank level of over 100 still concerns me though. The test kit over read tap by about 20mg/l so if its over reading the tank, that still puts me at about 80. Of course if its a log scale then the test kit over read the tap by 50% so it could be over reading the tank by 50% too which would make for much better water.

 

[Dinky Stig]

According to your water supplier, the nitrate levels in your water supply are to the UK standard which is <50 as long as your fish are showing no negative signs you're fine.

 

[waterdrop]

Jmac, were you saying it was goldfish you were worried about, that you'd read somewhere that they are particularly sensitive to nitrate(NO3)? I'm not a goldfish expert, so I have no real idea but on the surface it does seem far fetched that a somewhat hardy pond type fish like that would be very sensitive to NO3. I tend to agree that getting involved mixing up your own tap/RO mixture would probably be overkill. Not to sound like a broken record but OM47 is our man with a lot of RO operating experience that's handy to the beginners section. But I'd want some strong evidence prior to going to all that trouble.

~~waterdrop~~

 

[JMcQueen]

Jmac, were you saying it was goldfish you were worried about, that you'd read somewhere that they are particularly sensitive to nitrate(NO3)? I'm not a goldfish expert, so I have no real idea but on the surface it does seem far fetched that a somewhat hardy pond type fish like that would be very sensitive to NO3. I tend to agree that getting involved mixing up your own tap/RO mixture would probably be overkill. Not to sound like a broken record but OM47 is our man with a lot of RO operating experience that's handy to the beginners section. But I'd want some strong evidence prior to going to all that trouble.

~~waterdrop~~

Yes, that was me. Thats the probably with the internet. For every good bit of advice there are dozens of bad articles. The one I read which recommends keeping it to <20 for Goldfish seems extreme. Obviously if you can then great but saying 20 is harmful, really? I do have concenrs when it gets to around the 100 point though.