Can Nitrates CAUSE disease

[loans_n_fishes]

I know nitrates can stress fish/coral, but can it actually kill them (in and of itself)? How serious are high nitrate levels? There are times when I test that they are very high (off the chart high).

I have a dsb (around 4"-5" of crushed coral with a plenum over the bottom 2". How effective should this be? I also run a CPR RR bakpak (it is rated for a smaller tank than mine though). I put a handful of caulerpa in it to help with the reduction as well. My tank does not have a sump or a fuge. If I put a wad of algae in the main tank, my foxface will gobble it. What should I do to keep nitrates at bay naturally? I know water changes help, but what do I do in between?

[Richard]

Nitrates do not directly kill fish. All the studies show that nitrate in and of itself is not toxic to fish unless the levels are extremely high (far greater than you would ever get in your tank). That's what the studies show but I know tanks with really high nitrates tend to have much higher losses than tanks with lower nitrate levels. Usually high nitrate indicate poor overall water quality so perhaps poor overall water quality is responsible for the higher losses and not just the nitrate level.

Crushed coral is just the wrong size media to be using with a dsb, with or without a plenum. You should be using a finer substrate, either fine sand or the special grade aragonite made by carib sea. People have had good results with both. IME, tanks with crushed coral tend to have more problems with nitrate, phosphate etc. Probably because so much detritus can get trapped in the larger substrate and create a nutrient sink.

It would take ALOT of macroalgae to bring nitrates down from "off the chart".

[Ping]

Posted same time as richard

High nitrates can kill life in our aquariums. DSB using Course Substrate suffers faster detritus and sediment collection and does very little for denitrification. Sugar fine sand works best for denitrification, while aragonite is a very good medium by providing elements back to our systems as it disoves.

some natural ways to reduce nitrates for you may be:

Less fish
less feeding
larger skimmer
more water changes
MIracle mud type fuge
a remote fuge

Thats all I can think of right now. Anybody else.

[loans_n_fishes]

I think my substrate is the special grade aragonite. At least that was what I was attempting to buy. It's about the size of fresh water aquarium gravel. Is this small enough?

[kkutac001]

I have a FW tank as well as SW. I used gravel in the FW tank and always have high nitrate levels, which I've read is due to detritus accumulation. I believe it: I think my FW tank is proof. Regarding nitrates, I read that high levels can cause deterioration of the tissue structures in the gills of fish. ..Karl

[Richard]

Do you have a picture of it. The sg aragonite is much finer than most fw gravels.