Max Nitrate Troubleshooting

[Wwidener]

So I run a maintenance company and have a client with the attached 164g freshwater tank and sump. Livestock is one adult massive pleco and three medium angelfish. No live plants. Only carbon for chem filtration.

I have been working on her tank for two months and cannot get her nitrate levels below 200ppm. So much so that algae is clogging up her 7" filter sock in a matter of days.

I have done 50% water changes every week and even replaced the substrate with a 75% water change. The home was purchased with the tank in this condition.

I need ideas. I just added Purigen and have asked her to consider live plants in a refugium. What possibly could be causing such high nitrates? Ideas to decrease? Thanks.

 

[Wwidener]

So I run a maintenance company and have a client with the attached 164g freshwater tank and sump. Livestock is one adult massive pleco and three medium angelfish. No live plants. Only carbon for chem filtration.

I have been working on her tank for two months and cannot get her nitrate levels below 200ppm. So much so that algae is clogging up her 7" filter sock in a matter of days.

I have done 50% water changes every week and even replaced the substrate with a 75% water change. The home was purchased with the tank in this condition.

I need ideas. I just added Purigen and have asked her to consider live plants in a refugium. What possibly could be causing such high nitrates? Ideas to decrease? Thanks.

Here are the photos

 

[Delapool]

Apologies for question but I assume you have tested the tap water for nitrates just in case and to check test kit working ok?

Decreasing light intensity / duration will reduce algae. If green water could add a UV filter.

Cleaning filter media under hose, extensive gravel vac - I’ve found these will halve nitrates. Filter cleans with hose need some care - here the tap water doesn’t kill off bacteria

 

[Wwidener]

I tested the tap water with 40ppm results. I tested the kit on RODI to make sure it works.

I understand the lighting idea. I believe the brown gunk all in the filter is nitrifying bacteria eating off the nitrates. So I'm not 100% sure it's algae. There is zero light in the sump area.

When I do water changes, I siphon the gravel as much as possible.

 

[King Fisher]

Sounds like your client is overfeeding

 

[Wwidener]

Fisher, wouldn't that show up with increases in ammonia and nitrites?

 

[King Fisher]

Not if it's a well established tank with good BB. Your client has a very small amount of fish stock for that size tank or I think you would see ammonia in the tank from overfeeding.

I don't run sumps but I do run canister filters and if you overfeed they get clogged up big time with brown gunky slime. Same with HOB's. It'll actually stop the impeller in an HOB.

Clean the hell out of everything. I'd do 4 back to back 50% water changes.....Then have your client feed just 3 days out of 7, once during those days and moderately. Then test the water. I bet those nitrates aren't as high.