Need help - high NO3 level

[naturetan]

Would like to know whether I can change water everyday to reduce my NO3 level? What could be the cause of such high level?

I've just realised that my NO3 level is at the dangerously high level- 100mg/l. The last time I washed my external filter media is about 1-2 months ago. I've regualarly changed 1/3 of tank water every week. Yesterday changed 50% of water but the level still read the same. Check with tap water NO3, it reads about 12.5mg/l, using Tetra test kit I've just bought. Is the reading correct?

My water looks clear from front, but at the side, it looks a bit brownish cloudy. Has been like that since the last time I washed my filter media, as I unknowingly destroyed all its beneficial bacterial. Recently have BBA outbreaks. My tank is densely planted but with open space in front for glosso.

My bioload is just 13 Neon Tetras, few shrimps and 4 otos for a 55 litres tank water. Shrimps aren't doing well. What can contribute to such high NO3 level? Should I wash my filter again?

[wynx]

The reason why yout N03 reading is so high is because you never allow your filter/ beneficial bacteria to establish themselves to deal with the high nitrate...

Recommend you to change water but not the filter unless it get clogged up...

[naturetan]

Isn't it true that NO3 is the last thing that the Nitrogen cycle can go? Even if beneficial bacteria is established, it only can purify the water up to NO3, right?

[budak]

check again.... if really 100 mg/l your shrimp should be long dead.

[Allen_1971]

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On 3/24/2003 2:35:01 PM

The reason why yout N03 reading is so high is because you never allow your filter/ beneficial bacteria to establish themselves to deal with the high nitrate...
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Errr... If you are talking about the N-cycle, then NO3 is the last product in the stage. The fact that he has high NO3 means that his filter bacteria is alive and kicking. Its true that sometimes bacteria do the reverse and convert NO3 to NO2 through a process known as denitification, but this requries an anaerobic region while the bacterial in our filter needs an aerobic environment.

Whats unusual is that his NO3 is so high when his bioload is low.

Nature,

I have 3 guesses...

1) your test kit is faulty
2) you did not test properly... did you take your readings as directed (at the correct time)
3) you inserted a lot of fertilizer tabs like jobes or horti tabs which are leaching into the water.

[naturetan]

Guess my shrimps are all dead, yesterday just saw one, but now I'm not sure how many, since hidden. Just checked again, the color reading looks somewhere in between 50mg/l and 100mg/l(next marking).

I'm not sure whether test kit is accurate, that's why I tested it with tap water, color looks somewhere in between 0mg/l to 12.5mg/l. Is this the standard Singapore water for NO3, in case you know.

I think the 3rd possibility should be the likely cause. Just inserted a packet of intensive substrate fertiliser few weeks ago, as some part of the plants are not receiving fertilisation. Thought most fertiliser should have very low NO3?

What should I do now, take out whatever fertiliser I've inserted? Press it deeper? Or changed all to the slow release type? Is there a limit to the amount of fertiliser I can put?

[Allen_1971]

Nature,

perhaps you could check the contents of the type of fertilizer you inserted? In particular check the amount of N in each tab, and also the weight of each tab... In addition, how many tabs did you insert? Is it a fert meant for terrestrial plants?

[geoffrey]

I agree with Allen, you need to identify the source of that NO3. If it is coming from something you put into the tank, no amount of water change is going to help until you remove it.

[loupgarou]

check for dead shrimp.

one of my first tank of doom part 1 problems was dumping in 200 malayan shrimp = which died in hidden places and started rotting with high organic load resulting in bacterial bloom and dropsy in fish.

[naturetan]

This is the problem. It's a Taiwan brand without any indication of its content. If I remember, it's BRISTO, blue/white packaging bought mostly from Ah Pek at Pasir Ris. I used a packet of slow release type 2 months ago, about 10 of it. A month later, decided to insert more, so bought the same brand but not slow realease type, about 10 in a box with 1.5cm dia. by 3.5cm length. So altogether about 20 of those. No, they're meant for water plant.

Another possibility I think of is that I quite often uproot my plants, about once or more in 3 weeks, either changing its position, or replacing it with another type due to a wrong selection of plants. This might stired up lots of my initial fertiliser that I put during setup.

I'll make a thorough check on any dead matters. Any problem if I change the water immediately, or should wait for the chlorinated tap water to settle a few days before the change?

[Allen_1971]

thats a bit unusual.... most aquatic ferts are free of N and P... perhaps its a bad brand... try doing a 50% water change, and measuring your NO3 after that... then measure it again the next day to see if it still goes up....

[wahboy]

hello gang,

one way is check if your no3- is reallty that high is to plant some fast growers like rotala indica or rotala rotundifolia. if they are stunted after a while, that shows no3- is low and they are N limited. therefore your test kit is wrong.

but if they are always growing, that shows something is leeching from your substrate.

sounds logical and hopefully it helps

wahboy

[naturetan]

I've done 50% of the water change. NO3 measured after water change is about 25mg/l - 50mg/l (color looks more towards 50mg/l). Check the next day, reading still maintain. Seems like reading are gradually reducing with each water changes. The strange thing is after the changes, the reading is still high? Check reading against tap water again, same reading around 0mg/l - 12mg/l, so guess my test kit is working well.

A thorough search was done for any dead body, but can't find any. There're still about 5 or less shrimp surviving. Has taken out several of the woods, give it a scrub before putting back.

Can the rotting of plants and woods contribute to the NO3? The plant MM(Micranthemum micranthemoides) has been rather unsuccessful and keep rotting off. I've taken it out and hope when everything is back to normal, I would like to try again.

For several of the other plants, the bottom part (old leaves) shed lots of it recently. Initailly thought its N & P deficient due to low bioload, but surprisingly test N otherwise. Hopefully my plants can absorb the excess.

First is KH, now is NO3, not sure what's going to be next... Feel like taking out everything and start all over again, replacing it with a good branded substrate sand. []

[bclee]

Naturetan, looks like you may be deficient of a macronutrient, maybe K.

Questions:
What is your fertilisation regime?
Do you dose K?
What is your PO4 level?

BC

[naturetan]

Yes, it's deficient of macronutrient. That's why I'm trying to figure out what's wrong and bought the NO3 test kit, as suggested by Allen.

I used UP Flora and Ferro liquid fertiliser(Taiwan brand) every day, about 0.5-1 ml. No other dosing at the moment.

Just bought K2SO4, MgSO4, KH2PO4, and CaNO3. Last night just dose a little K2SO4. Not sure how to measure in grams and dose the right amount, if you can advice, please. Still trying to figure out whether I should get more test kit before the dose, since it's so expensive...

[juggler]

You can find more about dosing at these articles Introduction to Fertilizers for a Planted Tank and Calculating dosages of fertilizer elements for a planted tank.

Looks like those plant tabs you inserted were too much for the plants to take it. It's the same that if we put a lot of fertilisers in our potted plants, they wither too.

See if you dig out or siphon away the tabs as much as you can. Get some floating plants like Frogbits/ Salvinia/ Hornwort that can suck up a lot of excess nutrients.

If this fails as well, then you really have to reset your 2ft tank. It's a small tank only, don't worry. I did that for my 5ft tank when the substrate got something wrong after 1 week of planting. Almost gave up...[]

[bclee]

IMO, you don't have to worry about high NO3, as long as you keep up with the other nutrients like K and PO4. You will find NO3 gradually declining.

BC