Plants and Nitrates - Fact or Fiction

[Honey Badger 1]

Up to 40ppm is generally considered safe, but I like to keep an amount of fish and plants in my tank that keep the nitrates under 20ppm between water changes. 40ppm is "safe", but the lower the better, high nitrates are toxic to fish just like ammonia and nitrite.

[mermaidwannabe]

Trates of 40 ppm are right on the edge and allow you no wiggle room, should something prevent you from doing your WCs as per your regular schedule.

On the other hand, trates of 20 ppm or less give you a wider and safer margin. You should still do your regular maintenance, but if for some reason you inadvertantly overfeed or something holds you up from doing your maintenance as you normally would, the lower trate count gives you more time in which to correct the situation before the water becomes toxic.

Once they rise to 40 or higher, that's an emergency and you have to act NOW to get them back down, and it may take awhile depending on circumstances.

It's best to never let them get that high to begin with.

Filter-cleaning (but not overcleaning) will also help, along with regular WCs and keeping the substrate vacuumed. Plants contribute, but one shouldn't rely solely on them.

--mermaidwannabe

[Cermet]

There are no hard numbers for nitrates since most fish have different tolerances; that said, most fish that have been trank breed for generations will tolerate far higher than wilds. Some feel 40 ppm is the cut off and above is harmful but the best course is to keep it as close to zero as possible - nitrates ARE a waste material (via bacteria in the filter) that fish also need to keep out of their blood system and works against their ability to eliminate waste by their gills.

In the real world, most people do not want to try and achieve such low levels - dicus keepers are a significant exception - we aim for zero.

For really healthy fish, their is little excuse for nitrates above 20 ppm but life does not work that way and we try and do our best.

For that reason, I use an algae scrubber and my nitrates remain at zero (by API test kit) and under 1 ppm (Seachem). This has allowed me to do just a single 50% per week instead of a 50% and 70% each week.

Bottom line - do what you feel is best but I feel under 20 ppm is a good level to maintain.

[RylandVT]

I have both a 10 and 40 gallon that started out nonplanted and have been gradually been converting them to fully planted. Before adding plants, the 10 had nitrate of 20 with weekly PWC and the 40 had nitrates of 10-20 with twice weekly PWC. They both have what I consider to be a moderate amount of plants now but have very different nitrates. The 10 has nitrates at most 5 so I have to dose with ferts containing nitrogen to keep those plants healthy. The 40 has nitrates of 10-20 still. the big difference I think is the Amazon sword in the 10-that is such a heavy feeder. The 40 has mainly crypts and java fern. I hope this helps.