High Nitrate From Tap Water

[stoneagedinosaur]

Evening folks

My tap water runs at @ 50 - 75mg per litre - not too clever. Only just found this after noticing 50mg per litre in the tank for a couple of weeks despite lots of 25 - 50% water changes (Makes sense!).

LFS recommends buying their pure water then adding minerals - are they on the take or what? Does passing tap water through nitrate removing resin work effectively or is there anything that can be added to the water? The algae's loving it - but I'm not...

I know that planting some more 'live' plants will use up some of the nitrate - starving the algae, but it doesn't cure the problem.

All ideas welcome

 

[fatheadminnow]

Wow, sorry to hear that.

One thing that I would do is mix the tap water 50/50 with RO (Reverse Osmosis) water. This would at least bring your nitrate reading down to around 25 ppm, which would be more suitable for your fish. Other than that, I have no experience with Nitrate removing resin. I would stay clear of any chemicals that claim to lower the nitrate reading.

-FHM

 

[philak]

I see you are from Dorset. I made a similar observation on here about the high nitrate concentration at my g/fs place in Dorset some time ago although i believe the reading in her case was closer to 30ppm. I too struggled with water changes and couldn't understand why the tank always read 30-40ppm until i tested the tap water.

I think i read on the Wessex Water website that the legal nitrate limit is 50ppm so if you are hitting that mark or above then something is either wrong with your readings or something is wrong with the supply assuming i am right in saying that 50mpg/L is equivalent to 50ppm?.

I'm just glad that my local water is showing 0ppm nitrate .

 

[Harlequins]

Has a side thought,what test kit are you using?
If its an Api liquid test kit-the nitrate liquid can give misleading results if you don't shake the bottles until your arm falls off(well not literally )especially the 2nd bottle,the regeant gets stuck in the bottom of the bottle and needs a good shake to mix it up every time.

But if it is the water i can't help you nitrate removing resin - sorry

 

[Truck]

75ppm is fine, levels up to 400ppm are fine, scientific studies prove this.

they shouldn't go over 100ppm anyway if your keeping up with water changes, and plants will utilize some of the nitrate as well.

 

[stoneagedinosaur]

​

From Wessex Water website

The national standard regulated by the Drinking Water Inspectorate, DWI, states that water supply for public use must not exceed 11.3mg/l of nitrate.

Look like I need to write some emails!
It could be due to the high proportion of farms near my house and some dodgy silage recycling

 

[draconis]

I have the same problem. My tap water is usually high PH and 40 - 80 PPm Nitrates. Since summer I've been re-filling the tank with water coming from the icemaker filters on the fridge (GE's Smart Water + R.O. cartridges) and it has dropped to 10 - 20 PPM consistently since then. I'm a bit skeptical that the GE cartridge is a real R.O. system, but so far it seems to at least help.

@truckasauras123:
Now that the nitrates are reduced, I don't see the brown algae anymore, so at least this is motivation for reducing further.

 

[OldMan47]

If your filter is only dropping nitrates to 50%, it is not an RO but is a good filter for being nothing more than a cartridge. A typical RO will drop mineral content between 90 and 95% while a proper RO/DI arrangement, one often called RO in a shop, will almost completely remove ionic compounds.

 

[stoneagedinosaur]

If your filter is only dropping nitrates to 50%, it is not an RO but is a good filter for being nothing more than a cartridge. A typical RO will drop mineral content between 90 and 95% while a proper RO/DI arrangement, one often called RO in a shop, will almost completely remove ionic compounds.

Eh?

 

[OldMan47]

RO is reverse osmosis. It is a filter that is so fine that it lets water molecules pass but does not let larger molecules such as salts pass. It is called reverse osmosis because it uses pressure to overcome osmotic pressures across a semi-permeable membrane to move the water in what should be the wrong direction through that membrane. What is done with the more concentrated left behind is that it is sent to waste to prevent having it build up in concentration and stop the process. On average you will find that a home RO will waste from 4 to 10 times as much water as it produces. An RO/DI starts out with the RO which is only removing 90 to 95% of the impurities and passes the result through a resin column that contains a deionizing resin bed. The DI works by exchanging the positive and negative ions in the water with H+ and OH- ions that started out bound to the resin. When all of the ions on the resin are used up, you toss the resin bed and buy a new one. The result of using the combination is that the resin lasts much longer than when it is used alone and the water coming out of the DI is about as pure as distilled water.
Did that help any Dinosaur? I usually avoid the technical explanation because people do have trouble following it. I forget that sometimes want the whole thing.

 

[stoneagedinosaur]

Did that help any Dinosaur? I usually avoid the technical explanation because people do have trouble following it. I forget that sometimes want the whole thing.

Fortunately I am a science teacher and it all made sense to me! I read in a book about passing through a resin filter - now I know what it means.

Thanks for your help

 

[draconis]

RO is reverse osmosis. It is a filter that is so fine that it lets water molecules pass but does not let larger molecules such as salts pass. It is called reverse osmosis because it uses pressure to overcome osmotic pressures across a semi-permeable membrane to move the water in what should be the wrong direction through that membrane. What is done with the more concentrated left behind is that it is sent to waste to prevent having it build up in concentration and stop the process. On average you will find that a home RO will waste from 4 to 10 times as much water as it produces. An RO/DI starts out with the RO which is only removing 90 to 95% of the impurities and passes the result through a resin column that contains a deionizing resin bed. The DI works by exchanging the positive and negative ions in the water with H+ and OH- ions that started out bound to the resin. When all of the ions on the resin are used up, you toss the resin bed and buy a new one. The result of using the combination is that the resin lasts much longer than when it is used alone and the water coming out of the DI is about as pure as distilled water.
Did that help any Dinosaur? I usually avoid the technical explanation because people do have trouble following it. I forget that sometimes want the whole thing.

Thanks, excellent explanation. In summary:

It is NOT a true R.O. System if it does not generate waste water (which the GE filter does not) and does not use energy to create the required pressure (or can it use just pressure from the tap?). Correct?

 

[OldMan47]

My home type RO uses tap water to get the pressure it needs and has a very low pressure on the product side so that I get a differential pressure that can drive the flow. The waste stream is a constant bleed from the supply side, it more or less acts like the blowdown of mother liquor in a still. The very low pressure is enough to fill the storage container which uses a bladder divider and a low pressure air charge to expel the water from the separate tap that sits on my kitchen sink.

 

[Dave Spencer]

LFS recommends buying their pure water then adding minerals - are they on the take or what?

Maybe, maybe not. The reality is, there is no evidence to suggest that nitrates at 50ppm is harmful to your fish. Your test kit and what you may have read will suggest a problem. What do your fish think about this? They are the ones with the only opinion that matters.

I know that planting some more 'live' plants will use up some of the nitrate - starving the algae, but it doesn't cure the problem.

This statement is not correct. Plants and algae do not compete for nutrients. If they did, algae would win hands down due to its ability to thrive in nutrient limited environments.