fish, water and plants

Question
I have had my 50 gallon going with fish for 2 weeks now.  I have already used a full bottle of ph down on it over the past two weeks as the ph is around 8 to 8.5.  Doesn't seem to help as the fish start wiggling in one spot and one fish is already showing signs of ich.  The male molley has bulging eyes too. My plants the bushy ones that can float on top are starting to go brown at their tops and I am not sure why.  How can I check nitrate levels as I have a ph tester that just gives me the ph reading.  How long will a 50 gallon aquarium take to build its ecosystem?  I also notice the fish like to all go up and down one side of the aquarium a lot.  My catfish just died in the aqarium with buldgy eyes and discolored skin a few days ago.  My red tailed shark keeps taking a run at the stream coming from my aqaclear external filter system and then he jumps out of the tank into the filter system, which I end up putting him back in the tank.  If you can help me answer what I need to do to fix up this tank that would be great !

Answer
Hello,

First off, if your tank is new, it could take over a month to establish its nitrogen cycle. I recommend only having a small amount of fish during this time, as deaths are much more common.

Second, you should test for ammonia and nitrites primarily, and then worry about nitrates. You can buy test kits specifically for testing these. I recommend not using strips.

Third, you should leave you Ph alone for now. Once your nitrogen cycle it complete, if you would like to adjust ph that would be a good time. Right now there is already a lot of stress on your fish. PH needs to be adjusted slowly, and using a whole bottle of ph corrector in 2 weeks may be taking things a little too quickly.

Fourth, browning plants may be an indication of either not enough UV light or some sort of toxin in your water. This is another good reason to check ammonia, nitrites and nitrates.

Some fish like to jump out of the aquarium. I too had one that always found a way into the filter. The best way to prevent this would be to put some sort mesh (a piece of a fish net or a new pair of nylons perhaps) over the opening. That way the fish can not jump out, but if he tries to jump he will not be hurt because he will just hit a soft meshing.

I hope this helps.

Regards,
Stephanie