funny nitrAte readings

[silvershark]

ok so i went away for a few days last week and had my dear old gran do my feeding for me as she's the only person i trusted to listen exactly to my instructions, i tested the water stats a week before i went, which should've been when i did a water change anyways, and here's what i had:

ammonia:0
nitrIte:0
nitrAte:5

so i left the water till the day before my hols. here's the results:

ammonia:0
nitrIte:0
nitrAte:5

no change! so my wife and i discussed it and decided to leave the water till we got back as something would undoubtedly go horribly wrong, so i decided just to rinse out half of the filter media.
i got back after 5 days away to find that my filter had completely blocked so i did a water test and yet again i got exactly the same results. i found that my hygrophilia (spelling?!?!) had a massive growth spurt and a couple of the leaves had been sucked whole into the filter which had caused it to block.

would the excessive plant growth explain my low nitrAte readings?
if not, what could it be??

 

[iggy01]

would the excessive plant growth explain my low nitrAte readings?
if not, what could it be??

If your nitrate reading was a lot less than is usual prior to a water change, it is reasonable to suggest the rapid growth spurt of the hygrophilia could be responsibe. Hygrophilia is a fast growing plant under the right conditions. I have to trim mine every week....sometimes twice.

I don't know how heavilly planted your tank is, but nitrate in a well planted tank should never be allowed to drop below 5 mg/l. If it does, your plants are unlikely to grow to their full potential and you risk having an algae outbreak.

Good luck!

 

[Bignose]

Seems to me that the blocked filter combined with the rapid growth indicates that your plants were uptaking ammonia directly. Many aquatic plants uptake ammonia as their preferred food source. If the plant takes up ammonia, there is none to go through the cycle, and hence no cycle end products (nitrate). If you want a whole lot more information about how to effectively use your plants as the filtration, check out Diana Walstad's Ecology of the Planted Aquarium.