Nitrates off the chart!

[NewFishGuy]

Okay....you can see below to see the system I have....I know that Nitrates are not toxic to fish, but my nitrates are currently running at 160 ppm or above.

I had a cory cat disappear and I thought he had committed suicide by jumping out of the tank and being eaten by an eager cat or dog, but later found the decaying body inside a rock sculpture in my tank. My ammonia levels were WAY up (they are now getting back to normal, still high but dropping steadily.) and my nitrites were up also, but they are going back down also.

I tested the Nitrates 2x last night and got the same reading each time. I know you want to keep your nitrates below 40, but also hear all the time that they aren't toxic to fish. My question is....even at these levels they aren't toxic????

I also had an algae bloom in the tank due to the decaying cory....can the nitrate level be related to the algae bloom?

Also, anything other than water changes I can be doing to lower the nitrate levels?

Thanks in advance for any help!

edited to include current readings:

pH 6.4
Amonia 2.0
Nitrite .25
Nitrate 160+

[Frank_the_Tank]

they aren't toxic at low levels, but higher levels, especially something like 160 8O would really stress fish. Adding live plants will absorb nitrates, but that's about it other than pwc. algae will thrive off the nitrates (like live plants) so that's where the bloom is coming from. Lower the levels, and the algae won't have nutrients and will go away.

[grimlock3000]

Do a 20% water change every day until it drops below 40. It will not take too long to get there...