High Nitrate

[welshboy]

My brother inlaw as a 6FT tank, i am thinking to ask him if he would like it.Not sure what he as at the moment in his tank.Mark

 

[Skins]

Agree, but i have experienced a pH crash when nitrates have been 40/60ppm

Skins.

Not very scientifically conclusive, PH crashes can be caused by numerous things.

Tank is 39 galls, the pump is a powerhead with a under gravel filter.Fish 1 pleco' 6 clown loaches' 3 kissing gouramies' 4 sucker loaches'1 red tail shark'1 albino shark' 1 angle fish 3 guppies.Mark

First problem here is the under gravel filter, and is probably why you have high nitrate levels, due to the detritus building up in the substrate, I would switch to a large internal filter or an external filter. Also, the Pleco, what species is it? The Clown loaches will slowly out grow the tank but should be fine for a few years yet, but they do create a lot of waste, also the kissing gourami's will outgrow the tank, and probably the loaches too species dependant. The Sharks will probably fight as they mature, and they tend to become very aggressive also.

Hello Jack,
The only evidence that supports my findings are reference to my fishless cycle. When nitrate levels get between 40/60ppm my pH crashes, and yes i do have a low kH. My fishless cycle is being processed in a bare tank.

Skins.

 

[Skins]

Hi Mark,
I mentioned in one of my posts about having plants to lower nitrates, with you having a undergravel filter i'm led to believe this will hinder you to what plants you can have in the tank.

Skins.

 

[welshboy]

Hi' I do have plants in the tank plus a CO2 canister.Mark

 

[Skins]

Hi' I do have plants in the tank plus a CO2 canister.Mark

My mistake Mark, i was always led to believe there was issues with undergravel filters and roots of live plants in the gravel.

Skins.

 

[Jack_]

The plants wont be having much of an effect on nitrate, the realistic maximum for nitrate uptake is 5ppm per day, that is with 6WPG, full EI and full CO2 injection as demonstrated by Tom Barr, realistically you're looking at a maximum uptake of <2ppm unless you've got a high plant mass and lots of light.

 

[welshboy]

Hi' i'm not sure with under gravel filter with plants.I'll have to find out Thanks.Mark

 

[welshboy]

Hi Jack' Thanks alot for your help and information.I'll have to sort out a different way with a pump.Mark

 

[Skins]

Hi' i'm not sure with under gravel filter with plants.I'll have to find out Thanks.Mark

Mark, if your plants are healthy then they are fine with the undergravel filter, you must have a good ammount of subtrate.
Going back to your question try just perfoming bigger weekly water changes/gravel vac.

Skins.

 

[welshboy]

Hi Skins' yes i will do that, or maybe twice a week and see what happens.The plants are fine if the fish stop pulling them up when looking for food.Thanks for your help and information on the subject.Mark

 

[Skins]

Once again sorry for getting side tracked with Jack in your thread.

 

[Mikaila31]

The plants wont be having much of an effect on nitrate, the realistic maximum for nitrate uptake is 5ppm per day, that is with 6WPG, full EI and full CO2 injection as demonstrated by Tom Barr, realistically you're looking at a maximum uptake of <2ppm unless you've got a high plant mass and lots of light.

Yes, but you need to factor in that they will be consuming Ammonia much more readily. The biofilter will also be consuming ammonia too in a tank, so that has to be taken into consideration. But with plants, they may not reduce nitrate noticeably by uptaking NO3-, but they will consume some of the ammonia in the bioload and prevent it from being converted to nitrate. Of course how well this work depends on each tank. But this is the reason planted tanks are not cycled like non planted tanks. Its also the reason why a proper planted tank can be maintained without any filter. If I had to just guess I would say a tank with reduced filtration would probably see a bigger reduction in nitrates if it is a properly functioning planted tank. The main factor here is the competition between biofilter and plants, slowing down the biofilter I feel would give the plants a better chance at getting that ammonia before the filter does. But like I said its all just me guessing. Half of my tanks have no filter and one I know is filtered, but can function just fine if I remove the filter.

High nitrates can result in a pH crash IF you have soft water. The high nitrates here are not really the cause IMO. If you had simply added some mineral content to the water a crash could be avoided. Low hardness means weak buffering capacity, or the waters ability to withstand pH changes. Nitrate exists in your water as NO3-, but also as nitric acid HNO3. These two exist in a mobile equilibrium like ammonia and ammonium. When you allow their build up, but don't have the proper buffering capacity its pretty easy to say what will happen to the pH when you add even a little strong acid. Water with a decent buffering capacity would remain unaffected at this level. Preventing a crash is as easy as adding some baking soda it will up pH and KH, or tums it will up GH and probably pH, or epsom salts kinda......

 

[Curiosity101]

High nitrates are caused by one or a mixture of a few reasons...

1) High nitrates in tap water

2) Over stocked tank

3) Water changes too small

4) Over feeding

It doesn't sound like you're over feeding, and your tap water nitrates are low. Also if you're doing weekly water changes of 20% or so then this is normally plenty for a well stocked tank.

Judging by your stock list and tank size I would say the only reason you have high nitrates is because your tank is overstocked.

In the short term I suggest extra water changes. A couple of 50% changes will get the nitrates nice and low.

But long term you really need to address the fish in your tank and restock suitably. Or get a larger tank. 40-80ppm isn't dangerous, but it's still not good when the aim it to keep nitrates around 15-20ppm above tap water level max.

Also regarding your UG filter, personally I'm not a fan. They're harder to clean and more restrictive than internal/external box filters... but each to their own.
Point is this wont be causing your high nitrates, but do make sure you keep the gravel relatively detritus free to keep the filter working efficiently.

 

[Doc7]

I always wonder about keeping nitrates at a certain level with regular water changes...seems to me like you need to have bigger water changes than normal in order to do this.

Let's assume that at one's stocking level they produce 20 ppm nitrate per week. So after 1 week in a new (cycled) tank, you're at 20 ppm with the fish/food load you added on day 1.

Perform a 25% water change and this goes down to 16 PPM. After a week you'll be at 36 ppm nitrate. Do a 25% water change and you'll be down to 27. After another week you'll be at 47 ppm...

So does everyone actually do regular water changes, combined with a monthly (or more often) much LARGER water change to keep nitrates down??


(edit: 25% of 20 will bring you down to 15 ppm but the idea is still there and the numbers are easier, sorry)

 

[Curiosity101]

In a tank that isn't overstocked I doubt you'd be seeing an increase of 20ppm a week. All mine recieve 20%-30% weekly and never stray above 20ppm... If it did I would consider adding lots of plants or addressing my stocking level.