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.

[mrchoco]

a water change of 90%
my tank ongoing for 1 day already
my nitrate reads less than 5ppm
i think your test kit might have problem or you never rinse the container properly..

[CP]

my nitrate reads less than 5ppm
i think your test kit might have problem or you never rinse the container properly..

Er...my Tetra test kit scales are 0,12.5,25,50 and 100.Difficult to estimate in between figures.

However,see attached link for nitrate levels.Can range from 0.5 to 7 or up to 15 depending on which waterworks.Maybe Woodlands is from 'other' waterworks.


http://www.pub.gov.sg/our_services/WaterWS...2=8&l3=4-2&l4=3

[HappyBuddha]

Er...my Tetra test kit scales are 0,12.5,25,50 and 100.Difficult to estimate in between figures.

However,see attached link for nitrate levels.Can range from 0.5 to 7 or up to 15 depending on which waterworks.Maybe Woodlands is from 'other' waterworks.
http://www.pub.gov.sg/our_services/WaterWS...2=8&l3=4-2&l4=3

Thanks for the link.

I found a way to verify if your test kit is good.

According to Evian, their water has 1ppm of nitrate. Get a bottle of evian and test the nitrate level. If your test kit still register amber instead of a bright yellow (0 mg/l), then it's faulty.

The link to Evian's analysis of its product is

http://www.evian.com/us/corp/faq.html

Click on the 5th FAQ "What's in Evian Natural Spring Water".