50% water change and still 20ppm nitrates

[Bloodasp]

Try getting a new test kit, the one you have might have gone bad, old or contaminated.

[paddyob]

Originally Posted by Bloodasp

Try getting a new test kit, the one you have might have gone bad, old or contaminated.

I agree. I had an issue similar once with a calcium test kit. Was always getting results 700-800 instead of anywhere close to 440. I changed test kit and results were terrific.

I would try this before trying more water changes.

[Milad]

well im sure its high nitrates since the algea is going crazy on the glass
also oil slick on the top of the water

the test kit also reads no nitrates on the water that im using to change with.

Only dead animal i see is a halloween crab i bought the other day, seem to have died quickly, just saw his legs laying around.

[o.c.d.]

Have you recently used any Gfo if so was it more than you usually put in?

[Milad]

no GFO, actually I removed both bags of rowphos when i started zeoviting. 500ml total.

[o.c.d.]

I ask because when you remove po4 quickly out of the tank the bacteria feeding on it will die then cause a spike in nitrate. Even large waterchanges to me are not a good idea. slower is better.
Now zeobak isn't that the food source for the bacteria that live on the zeolite? If so by stopping dosing you quickly removed the food source maybe causing the same effect.