Default Nitrate Levels Options

[CP]

I am talking bio tanks here.

Frankly,I have not bothered about nitrate levels for the past year since I took up this hobby.My stock level is low (750l for 9 fishes),I do 30% water changes forthnightly,the fishes growing well and no diseases (touch wood) so far.

Until I chance upon RafflesGold forum.After browsing thru the old threads and subscribe to the advice of keeping nitrate levels below 50ppm,got myself a Tetra test kit 3 wks ago and... WAH PIANG!!Turned red in no time!Performed 80% water change immediately and still red!Performed another change and brought down to abt 25.

Whew,I thot,the level must have been in the hundreds to begin with.After the first week I find that I need to perform at least 50% change weekly at the current stock and feeding level to keep it below 50.

Now-straight to the point.I found that when I did 80% change (lazy to net fish out la) at 50ppm I was expecting nitrates to be abt 10 (0.2x50=10)afterwards but found that its abt 25.After the next water change (same parameters) also discovered abt 25.The maths don't tally.So I tested tap water - wtf already 12.5!Checked PUB website and found that nitrates in tap water can be up to 15ppm.

There you have it - After water change 10.
Tap water 12.5

The rest?In my opinion from the ammonia freed from chloramines (chloramine = ammonia + chlorine) after adding the water conditioner which was subsequently coverted to nitrates as well.I reckon it can be abt 2ppm judging from the recommended chlorine residual level from PUB website.

Therefore I conclude that even after you change 100% of water,the default nitrate level shd be abt 15ppm.You may think that I am mad for dwelling into these figures but after browsing the old threads I take comfort that there is a self- proclaimed nut case who keeps the nitrates levels below 40(or is it 20,I cant remember.)

That's all.Time to change water.

[HappyBuddha]

Excellent work and a delightful read too!

I'm out of a nitrate test kit so I can't test the nitrate level of my tap water. Over a year ago when I kept a record of the water parameters (for my bio-green experiment), I did recorded nitrate at zero level after water change. So I'm wondering either the water supply have changed quite drastically since, or maybe your test kit is faulty/expired?

But you got me curious and I'll go get a new kit (from the distributor to ensure freshness) to find out what the nitrate level is like over here compared to woodlands.