Nitrate level after water change

[Litespeed]

Before we did our 25% water change this morning we had a nitrate reading of 20. After the change, the nitrate reading was still the same. Generally after a water change it will drop to 10. The only thing different that we did was add a carbon filter to take out the rest of the medication and my husband cleaned off a lot of brown algae from around the top inside of the tank and cleaned the sides of the tank. If any algae had gotten back into the water, would that have anything to do with the readings? The ammonia and nitrite levels are at 0.

[mitcore]

i am unsure on the algae upping your nitrate levels though i would have to say it seems unlikely as we all have algae in the tanks and dont usually spike a high reading from it, of course i am talking about me,

did you give the gravel a good clean, you might have left some junk in the bottom of the tank, and i take it the filter system got cleaned well?

do you have plants in there? are they plastic?
if so then did they get cleaned off well?

the carbon would have not changed the nitrate level, so i wouldnt worry about that,
is your tank overstocked? that can also up your nitrates though to be honest that usually starts to happen a few days after a water change

hope this helps a bit

[Litespeed]

We are definitely NOT overstocked with fish. We gave the plastic plants (most of them) a good cleaning along with the gravel. We didn't clean the filter except to take out the white filter pad and replace it with the carbon pad. The filter manufacturer said that the filter only needs to be completely torn apart and cleaned every 6 months and it does have an indicator on it that shows you when the flow is getting slower. I'm going to test the Nitrates again this afternoon and see if there is any change.

[Sniffles]

If I think my nitrAte levels are high I always wait a few hours after a water change to test it again to give every thing a chance to surculate real good.

[NickFish]

Nitrate tests can be really inaccurate sometimes if you have one of those API test kits. You have to shake all the stuff and if you don't shake for exactly what the bottle tells you you can get a much different reading. Test again now see if anythings changed.

If you want you can always step up the water changes.

[Fishguy2727]

Two possibilities.

1:
Your source water is higher in nitrate than usual.

2: Filters need to be cleaned much more often than every six months, no matter the filter. In another thread I described the effect of my neglected Fluval FX5. The nitrate concentration had been holding at about 40ppm. After I cleaned it the nitrate concentration was only 10ppm. This was the only change. Wate rchanges were bring it down to 30ppm, but it was pretty much holding at 40ppm. This is with 80% water changes. So you can see how bad the effects of a neglected filter can be. The filter COLLECTS the debris, it does not REMOVE it, that is YOUR job. If it sits there too long then it will start to breakdown, the end product being nitrate.

[Litespeed]

We did another 25% water change and removed a decoration that had not been cleaned for a couple of months. When we took it out of the tank, it smelled terrible. I cleaned it well with a weak solution of water and bleach and rinsed well. We have not put it back into the tank yet. I tested the water right after the change and nitrate level had dropped to 10 - 15. I will do another water test tomorrow morning.
How often should an Eheim 2028 filter be throughly cleaned?

[Fishguy2727]

Any filter should be cleaned at least monthly.

[Lady Hobbs]

I sooooo agree. Dirty filters don't do much good if they are full of gunk and pushing that stuff back into the water.