2 sick fish \ water param problem

[NDininno]

Main tank:

Nitrates: 40
Nitrites: 0
Hard: 120ppm
Alk: 90
PH: 6.9

Q-tank
Nitrates: 0
Nitrites: 0
Hard: 120ppm
Alk: 90
PH: 6.9


Had a platy get bloat\scales sticking out and a clown pleco get a bit of fungus on its head. These happened at the same time and I set up a q-tank immediately with a heater and bubble stone. I started on Maracyn-two 3 days ago and the pleco's fungus has gone down, though I'm not sure if it's bloated. The platy is still bloated. Here is the wierd part. The fungus is now all over teh piece of PVC I have in there, some is free floating, and some is on the heater... I have never seen this before, though I guess in the 2 years I've been fishkeeping I can't say I'm an authority on this sort of thing.

I know the nitrates are a bit high, and I'm trying to figure out why that has all of a sudden changed in my main tank. I've been doing daily 15% water changes since I discovered the problem 3 days ago and the nitrates are not going down. They have remained constant for the most part.

[NDininno]

Anyone have any thoughts ?

[Diana]

Fish keep adding ammonia to the tank 24/7.
Beneficial bacteria keep turning ammonia into nitrite, and nitrite into nitrate.
So you have a never-ending supply of nitrate.

Live plants will use a lot of nitrogen when they are growing fast, but other than that water changes are the only way to drop the nitrate level.

Sometimes the fish keep producing more ammonia (>nitrite>nitrate) than your water changes are removing. Do bigger water changes.

Sometimes the test results are hard to read, and the level really is dropping, but not very much, not enough to show clearly on the tests.

[NDininno]

OK, that's reassuring. But what about the wierd fungus now overtaking my q-tank?