Nitrate Nightmare

[Doobdonk]

Hi,

I have a frustrating issue with nitrate levels in my tank, and am looking for a relatively simple way to reduce the levels to acceptable. At present the levels have caused no noticable stress or losses but i need to take precautions.

Ok, tank has been running since January, ammonia and nitrite at 0, but nitrate at 40-50+.

The problem is that the water comes out of the tap at a level of around 40-50. Now, i do have an RO unit, but it's clearly not functioning correctly as water out of it is still at high levels, but i cannot afford to replace it again as i always saw it as a luxury. If it's a complete last resort, then i will obviously have to.

I have some plants in the tank, have never had major algae problems other than a green dust algae on the glass, and a brown algae that seemed to appear when my lighting levels were too low (now rectified).

My tank is 20G long, with two six(ish) month old angels, and two rainbows.

I run an external filter, water a constant 27c, fish very happy.

I did try those nitrate absorbing pebble things, but they only absorb a small amount if any, and it could only ever be a short term fix.

 

[k.o.d]

In my ray tanks even with massive water changes my nitrates are slightly higher than that so I wouldnt worry too much.

What is the nitrate level coming out of your RO unit?

Water changes with a properly functioning RO is the best way as your tapwater is not the best

 

[Doobdonk]

It seems to be around 25/30 coming out of the RO unit.

 

[k.o.d]

Have you a TDS meter? The maximum reading from a functioning RO unit should be no more than 10ppm.
Not teaching you to suck eggs, but have you plumbed it in properly? Are you reading the brine side rather than the product?
If the water coming into the tank is 25/30, you are doing a really good job to keep it at 40-50

First thing I would do is look at your RO unit

 

[Doobdonk]

Have you a TDS meter? The maximum reading from a functioning RO unit should be no more than 10ppm.
Not teaching you to suck eggs, but have you plumbed it in properly? Are you reading the brine side rather than the product?
If the water coming into the tank is 25/30, you are doing a really good job to keep it at 40-50

First thing I would do is look at your RO unit

Hi,

yep, seems to be plumbed in correctly, takes me an age to fill a bucket and i'd guesstimate that i only get around 10% of the water i run through it. I haven't got a TDS meter, will have a look on ebay.

 

[k.o.d]

Rather than go to the expense of buying a TDS meter, take it to your LFS and ask them to check, if they are a good shop they should have a TDS meter.
Your reject rate is quite high, we have a 100gpd unit with a pump and we get 1 gall of RO for 4 waste galls.

 

[Fwapp]

I have the same problem with high Nitrates. I'm currently considering a DI water unit, with a carbon prefilter. I've heard that adding a DI unit to the end of a RO unit with 'polish' off the last bit of nasties present in the water. Osmotics (top right hand corners advertisement of the forum) have some you can add to your unit, ring them for some advice.

Hope this helps!

 

[k.o.d]

DI units in areas with lots of contaminants in the water are hellish expensive to run, and they cannot be recharged.
An RO unit is much cheaper in the long run to use

 

[Fwapp]

DI Units can be recharged, or at least replace the resin. Thats why you are able to buy resin for re-useable cartridges

Link One

Link Two

Hope this helps!

 

[k.o.d]

You replace the resin and in hard water areas that makes it really expensive

Steve