Need help with Nitrates in Oscar's tank!

[DRoller]

Hello I am new to the site need some advice on Nitrates for my 2 year old 12" Oscar's tank. He is in a 125 gallon that’s been up and cycled I think about 8 months now. In the tank with him is 3 Convicts about 3’ long and a Plecostomas that’s about 11” long. I am running two Rena canister filters an XP2 and an XP3. Both of them starting at the bottom have sponge filters for the large stuff then into the ceramic rings and bio stars into activated carbon topped off with multi stage filter pad. Tank has ¼” river rock for substrate and two pieces of driftwood. My source water parameter’s are 8.0 PH,0.0 Ammonia, 0.0 Nitrites and 5.0 Nitrates using the API master kit. The tank water checks 8.0 PH, 0.0 Ammonia, 0.0 Nitrites and 160+ Nitrates. I do a 50% water change and very through gravel vac. about every 4-6 days depending on my schedule and when I do I dose with Prime, after 24 hours I check my Nitrates they are down to 60 – 80. I will check my Nitrates two days after my water change and they are back up to 160. I have tried back to back water changes and had them down to 10 but within a week they were right back up there.
Here is where my inexperience comes in:
How do people keep their tanks between 10-20 on Nitrates only doing a water change once a week or even once every two weeks?
Is there something I did wrong when cycling my tank? ( and yes I learnt the hard way about cycling a tank could not wait )

Please any advice is greatly appreciated Thanks,
Dean
P.S. this is how I feel

 

[Jmunroe]

You did nothing wrong. Your cycled or it wouldn't be converting to nitrates and there would be ammonia and nitrites. Your bio load is high with the large pleco. An oscar and pleco are both high bioload and in a 125 that's a lot. I have a 125 with an oscar and 5 silver dollars. I had 2 O's and am working on raising a second right now for the tank. Do back to back to back large water changes( right now I'm doing 60% or so every 4 days) gravel vac really well and only feed every 2 days. Get it down to 10 again, and every second day feeding should go 3-4 days before back to 40 or so.

 

[Jmunroe]

Silver dollars eat oscar poo since oscars only partially digest their food which helps a bit. What is your filter? It may need a cleaning to get some debris out that may be creating nitrates as well

 

[Jmunroe]

Just reread and see it's two canisters. You don't need carbon, wasted space for bio media. Use carbon to remove meds if needed

 

[DRoller]

You did nothing wrong. Your cycled or it wouldn't be converting to nitrates and there would be ammonia and nitrites. Your bio load is high with the large pleco. An oscar and pleco are both high bioload and in a 125 that's a lot. I have a 125 with an oscar and 5 silver dollars. I had 2 O's and am working on raising a second right now for the tank. Do back to back to back large water changes( right now I'm doing 60% or so every 4 days) gravel vac really well and only feed every 2 days. Get it down to 10 again, and every second day feeding should go 3-4 days before back to 40 or so.

Wow every other day feeding he might go thru the tank when I walk by on the off days!! I get home from work and he is dancing around waiting to be feed!

 

[DRoller]

Silver dollars eat oscar poo since oscars only partially digest their food which helps a bit. What is your filter? It may need a cleaning to get some debris out that may be creating nitrates as well

So would Silver dollars go well with the 3 Convict's I have or would that just add more to the bio load?

 

[DRoller]

I have read that about carbon on other sites, just kind of set my canisters up how my friend had the XP2 set up when I got it from him.

 

[Jmunroe]

I wouldn't add any silver dollars now. A lot in there already and yeah the convicts may not like them at all. If your oscar is over 8-9 inches then yeah he should only be fed every couple days. It's actually healthier for them then every day.

Best oscar/cichlid site avaliable

http://www.oscarfishlover.com/index.php

 

[HN1]

The last thing I'd do is to add fish.

I'd say, bigger filters &/or more water changes &/or less food will likely be your solution. How often and how much water do you change?

 

[Cactuspixie]

I agree with larger, more frequent water changes- whatever it takes to get and keep your nitrates under 20pmm is what you need to do. The alternative is to reduce your stocking level to lower the bioload.
ETA: when doing pwc make sure that you give the gravel a good clean and suck up all the waste you can. You may also need to rinse your media more regularly if mulm is building up in your filters.

 

[DRoller]

Yes he is like 12" to 13". I guess I need to get some self controll on feeding him!!

I have tried like three or four times to get on that site with no luck can't even get moderator to email me back!

 

[DRoller]

The last thing I'd do is to add fish.

I'd say, bigger filters &/or more water changes &/or less food will likely be your solution. How often and how much water do you change?

I do 50% water change every 4-6 days. Bigger filters, any suggestions?

 

[DRoller]

I agree with larger, more frequent water changes- whatever it takes to get and keep your nitrates under 20pmm is what you need to do. The alternative is to reduce your stocking level to lower the bioload.
ETA: when doing pwc make sure that you give the gravel a good clean and suck up all the waste you can. You may also need to rinse your media more regularly if mulm is building up in your filters.

I do what I would say a through gravel vac when I do the PWC. I use a Python when cleaning. Every other time I do clean I move everything around and clean up good.

 

[DRoller]

Is there any BB that grows in the substrate that I could be killing by doing such a through cleaning of my substrate? Only reason I ask is a guy at the LFS not LPS was was telling me not to gravel vac but every other time I do a PWC. The only reason I ask is because it was at the fish store not a pet store.

 

[Jmunroe]

If your combined canister filters are turning over the tank volume around 8-10 times an hour which is good for large messy fish with canisters you should be good for filtration. You would need more if the ammonia and nitrites were slow to turn into nitrates. Only way to get rid of nitrates is water changes. Do more of them and feed less maybe clean your filters gently but don't hurt your beneficial bacteria. You'll find a good balance between feeding, cleaning and water changes to keep things good for a few days. The more water changes you do the closer your tank becomes to your tap and this allows you to do more and bigger water changes without worrying about how your fish will like all the new water. My fish love 60-75% water changes every 3-4 days. Once my new o gets in my tank I have to reduce my feedings as well.

 

[Jmunroe]

Is there any BB that grows in the substrate that I could be killing by doing such a through cleaning of my substrate? Only reason I ask is a guy at the LFS not LPS was was telling me not to gravel vac but every other time I do a PWC. The only reason I ask is because it was at the fish store not a pet store.

Better to get the crap out of the gravel and let your filter do its job. Shooting yourself in the foot to leave crap in the gravel to save a little bb. I never understood why people would leave all that junk in the gravel to save some bb. The bb in the gravel would not be enough to deal with the crap left in there.

 

[DRoller]

If your combined canister filters are turning over the tank volume around 8-10 times an hour which is good for large messy fish with canisters you should be good for filtration. You would need more if the ammonia and nitrites were slow to turn into nitrates. Only way to get rid of nitrates is water changes. Do more of them and feed less maybe clean your filters gently but don't hurt your beneficial bacteria. You'll find a good balance between feeding, cleaning and water changes to keep things good for a few days. The more water changes you do the closer your tank becomes to your tap and this allows you to do more and bigger water changes without worrying about how your fish will like all the new water. My fish love 60-75% water changes every 3-4 days. Once my new o gets in my tank I have to reduce my feedings as well.

According to my research of my two filters I'm running about 600 gallons an hour to be on the safe side I would estimate 500 so that's about a 4 time turn over rate. I have not noticed any Ammonia or Nitrites when checking my water which I do about 3 times a week.

 

[DRoller]

Better to get the crap out of the gravel and let your filter do its job. Shooting yourself in the foot to leave crap in the gravel to save a little bb. I never understood why people would leave all that junk in the gravel to save some bb. The bb in the gravel would not be enough to deal with the crap left in there.

That's what I was thinking but being frustrated and still learning I have given it some thought.

 

[bshenanagins]

You could look into building a nitrate reactor with seachems denitrate. And so I don't bunch anyone's drawers here with this lol, it is not a replacement for a typical WC schedule. You'll have to maintain them to take care of typical TDS build up, but the reactor will help keep your nitrates at bay.

 

[mikem691]

You may just need larger pwcs twice a week