nitrates high after water changes?

[dandaman352]

Hey guys another question from me, I've been doing alot of water changes recently (this weekend I did 3 of them 2 were 20% the other was like 40-50%) anyway, I would test my water afterwards and shockingly I would still have a significant amount of nitrates in my water. I just took another test so I can give you the elements of my water..

PH- 6.2
Alk- 40
Hardness- 45 ppm
Ammonia , Nitrite - 0

NITRATES - 20???

Its a 75 gallon tank, non planted (fake plants for hiding spots), i use RO water with RO right and discus essentials, as well as prime.

I feed them a brineshrimp/spirulina mix from hikari, bh, spectrum discus pellets and flakes.

In the tank are 7 - 2.5-3.5 inch discus with 2 tri color sharks , 2 irredescent sharks, 2 elephant noses , 2 cory cats, 1 weather loach.

Any ideas on how I can keep it lower or whats causing this?

[ILLUSN]

test your tap water, it might be in there, if it is add some nitrosorb to your filter, 2 pouches should do it.

[dandaman352]

Wouldn't the RO filter remove it?

[ILLUSN]

it'll bring it down, but it'll take a very good, very well maintained unit to get it to zero (expect a rejection rate of 98% +).

still with pure ro water it should be below 5,

are you over feeding? is all uneaten food removed daily? do you gravel vac every water change?

[dandaman352]

I dont overfeed, and I remove all the uneaten food (well most of it whatever i can get into) and yes i gravel vac every water change, my last water change there was nothing to even vac which is why i couldnt understand why its like this.

[ILLUSN]

sound strange mate, whens the last time you cleaned the filter?

[Merrilyn]

Have you ever tested your tap water before it goes thru the RO unit?

It's got to be coming from the water.

You could try a few floating surface plants to soak up some of that nitrate. Duckweed is great, but can get out of hand. Wisteria is another good one. Check your LFS and see what plants they have.

[dandaman352]

I just cleaned my filter actually and changed the media.

Do those surface plants need anything special to live like lighting, co2 , etc?

I'll run a check on the water, if its the water what can I do to remove it? Prime?

[Merrilyn]

Those surface plants don't need anything special.

They do need some light, but just normal tank light is fine, and they'll get all the nutrients they need from the water.

We have a product here in Aus called "Nitrazorb". It's a pouch that you put in your filter. Don't recall the maker, could be Seachem, but I'm sure you can get something similar where you are.

[dandaman352]

Cool, im sure i can get it. Thanks