Why High Nitrates? Discuss.

As the title says I just checked in the community calculator and I'm only 36% stocked and have been for at least 2 months and I've still got off the scale nitrates. Tap is 40ppm. Very hard water.

You've seen photos of my tank, its quite densely planted, although I had a gardening session in there this week. John Innes seed compost, topped with white sand as substrate. Liquid carbon dosed daily and iron supplement weekly. 

I don't think I overfeed my fish. 1 soft algae pellet, a pinch of dried flaked food, courgette slice every 2 days and half a cube of bloodworms twice a week isn't excessive.

I did have an oversized internal and this week I fitted a fluval 206 external filter.

Sooo why are my nitrates so high?

I've been using the liquid carbon in the QT too since I got it. You use the same source for it Simon, I've no idea how to test it with my API test kit, however the nitrates in the 200l were high even before I was using that product.

I'd say that it's highly unlikely that the liquid carbon is adding nitrates.

Can't remember details about this tank? Has it been set up for long? Are your plants growing strongly? Plants only use nitrogen sources when they are growing. I've found floating plants to be by far the most efficient at reducing nitrate.

But really, I've no idea ......................... seems quite mysterious.

I emailed my water supplier and my tap water is treated with chloramine and I use a fluval aqua plus water conditioner which removes chlorine and chloramine.

I recently bought tetra test strips and they indicate the nitrates in the 200l tank are 50ppm, which isnt bad considering my tap water is 40ppm. The API test was unreadable to my eyes and showed as being somewhere between 40-80ppm.

I also recently acquired some amazonian frogbit which has reduced the nitrates in the shrimpery to 20ppm prior to a water change.

I was chatting to the guy in MA yesterday who lives up the road to me and he says in his densely planted tanks he never does a water change. He just tops the tanks up so the tap water acts as a buffer. We have very hard water in our area. So I'm going to try and do the same in my shrimpery. Hopefully the carpeting plant will eventually cover the majority of the substrate and the poop will filter down through the fine gravel and convert to plant food for them and the other plants I have growing. Thats the eventual aim anyway. I'd like to be able to do the same with the other tanks but as one has stiphs in it and they dig everywhere it's unlikely to happen in that tank while I have them and my son's tank doesnt contain soil.

I take it you have hard water as well Richard?

Hello. I'm sorry your having a bad time.  I was getting some but very small amount nitrites in my tank but think mine was due to changing to external filter and messing around with media. Plus I was getting bit of cloudy water. I spoke to my lfs and asked if he coukd help. He told me to try arcadia poly-filter. I done some reading up on it and must admit I was impressed. I purchased some and placed it in my filter.  The next day I checked my levels.  Nitrite was gone and nitrates had lowered. Also my phosphates lowered so that will help with the algae I was getting. Plus the water has cleared.  I'm so pleased. I'm always going to use them now. It's white pad and the change colour to tell you what it's taken out and turns black when it's done with and it's time to change it. It takes bad stuff out the water of the right amount that needs to conduct out.  Just thought I'd mention it incase it can help you reduce your nitrates as it states it does and has mine. Good luck
Maria

Thanks for the advice Maria. I do have polyfilter but for the reasons Sue stated I just use it to remove meds.

Thats why I used seed compost, it's got a very low nutrient base. I'm going to redo the entire tank after I finish college and replace that back and sides with soil topped with fine gravel. Hopefully the plants will grow better and that'll help nitrate levels in the tank.

I had high nitrates last year, ordered and got 3 ceretopteris plants, which did exactly what I'd read on the Internet. They sucked the nitrates right out

Thanks Rosaleen, I'll try and get hold of some when I redo my tank in a couple of weeks, the brown algae would just smother it at the moment.