Nitrate removal

[AltcarBob]

Hi all I have been a fish keeper for three years now but this year I have been having problems with algae. I bought a test kit and this showed I have Nitrate at approximately 40 to 50 mg's. I have spent hours changing water doing 25% water changes every day till the Nitrate was at the bottom of the scale. I go back to doing a 25% weekly change and the Nitrate bounces back up to the previous level. Still got the algae as well.

Tank is 120 litre with a 200 litre per hour can filter. It's got lots of plants and moss balls and a sand and gravel base. Fish are Tetras and Cory's with some Shrimps.

Can anyone suggest a way of reducing the Nitrate that doesn't involve me climbing the stairs with buckets of water every day.

 

[KevinZ]

Have you check you tap water? Some country tap water contains Nitrate. Idk where is the specific place. What test kit brand did you use?

 

[Essjay]

The UK allows up to 50 ppm in drinking water, so yes, check your tap water nitrate.

Apart from it coming in with tap water there are other causes.

Too many fish
Feeding the fish too much
Water changes not often enough or big enough
Not cleaning the filter often enough

The more fish there are, the more ammonia they make which is turned into nitrate. And over feeding means decomposing food which makes ammonia which is turned into nitrate.
Water changes should be at least 50% every week. 25% water changes will reduce nitrate that is being made in the tank but larger water changes will get it lower faster.
Filters should be cleaned at least once a month with once every two weeks being better. The brown goo that build up in there is a 'nitrate factory' - decomposing uneaten food, decomposing fish poop, decomposing bits of dead plant.

If any of these apply to your tank, this could be the problem.

 

[Byron]

Agree with other members here. If as you say you do get nitrate down to zero (assume this may be what you mean by nitrate at the bottom of the scale after water changes) then it is definitely occurring from within the tank. Essjay covered this.

Nitrate is poisonous to fish. It is not rapid, as ammonia and nitrite are, but it does slowly weaken the fish. It should always be as low as absolutely possible.

 

[AltcarBob]

Agree with other members here. If as you say you do get nitrate down to zero (assume this may be what you mean by nitrate at the bottom of the scale after water changes) then it is definitely occurring from within the tank. Essjay covered this.

Nitrate is poisonous to fish. It is not rapid, as ammonia and nitrite are, but it does slowly weaken the fish. It should always be as low as absolutely possible.

I can get the Nitrate down to as low as the scale goes on the tester which is 5 to 10.

I have started the 25% daily water changes and the fish will be going on a diet I was thinking feed them 2 days out of 3. I have given all the filtration a clean their was a fair bit of gunk in the pipes.

What Nitrate level should I aim for it has been as high as 80 m.

 

[AltcarBob]

I checked my tap water and that's showing as 10 on the test scale.

 

[seangee]

If it dropped to an acceptable level with daily 25% changes then it is likely that you need bigger weekly changes. I change 75% in all my tanks every week. Everything @essjay says will help.
What do you mean by lots of plants? Lots of fast growing plants will help keep it in check but bigger weekly changes are still recommended for a lot of reasons other than nitrate control.

 

[seangee]

I checked my tap water and that's showing as 10 on the test scale.

10 is fine. The tank in my signature is very heavily stocked. It starts each week at 0 and never goes above 5. On that basis you should aim to keep yours below 15.

 

[Byron]

I can get the Nitrate down to as low as the scale goes on the tester which is 5 to 10.

I have started the 25% daily water changes and the fish will be going on a diet I was thinking feed them 2 days out of 3. I have given all the filtration a clean their was a fair bit of gunk in the pipes.

What Nitrate level should I aim for it has been as high as 80 m.

You want nitrate as low as abnsollutely possible. Zero would be ideal, but not very realistic, although in well planted tanks running on a natural or low-tech method this is often the case, zero nitrates. The other thing is it should never rise significantly from water change to water change. The point of doing a substantial weekly water change (I do 65-75% sometimes even 80% every week at one go) is to maintain a more stable water chemistry, and part of this is the lowest nitrate possible. If you have nitrate in the tap water, you obviously cannot get the tank lower than that, and probably up a bit, but keeping nitrates as low as possible will mean healthier fish.

 

[Wills]

Its fair to say that you are putting in a lot of effort to deal with this so well done there really admirable commitment to your tank and fish.

I agree with what people have said above but I am wondering like seangee said what plants you have and if the addition of some properly fast growing plants could help soak some more of it up? Floating plants can really help - I've seen a really cool trick of growing it in or around rings of air-tubing which helps prevent it taking over the whole tank (though you will probably remove hand fulls each week). Or something like Hygrophila Siamensis '53b' would really help but again would need big chunks taking out each week.

Wills

 

[AltcarBob]

I inherited the plants so not sure what they are called apart from half a dozen moss balls and a red Iris.

I like the idea of floating plants I have duckweed in the garden would that work contained in a air tube corralled area.

 

[seangee]

Just to confirm that, the frogbit you see in my signature looks like this from above. I constrain it to 50% of the tank with a physical barrier and removing handfuls is dead easy. Don't pick something with small leaves like duckweed as that is a PITA. Just seen your post - re-read my last sentence

The plant on the right side of this tank is the Hygrophila Siamensis '53b' Wills mentions. Its actually not that hard - just clip it with a pair of scissors once a month or so.

 

[AltcarBob]

Quick update on progress. I have cleaned the tank, the filter can, the pipework and all the plants and all the items in the tank. I have been doing 25% water changes every 3 days, I remove some plant leaves at each water change and any leaves that look a bit brown are whipped out and the fish think I have them on starvation rations.

As a result I have got the Nitrate down to an average of about 15 (tap water is 10) and the tank is sparkling apart from the corner I cant get my scraper into because of all the pipework but even thats looking better.

I am going to keep up this regime but I dont know if the fish appreciate it though how do I tell if the fish arent getting enough food.

 

[Wills]

Thats really great news! Well done for putting in the work!

How are your plants doing? If you can find the right mix that grow vigourously in your set up there is a decent chance they would soak up a couple ppm of Nitrate for you week to week.

Wills

 

[AltcarBob]

Plants seem to be doing fine definite signs of fresh green growth. I am looking at getting some new plants and change the tank look a bit.