Chemistry help.

A black ghost knife will out gorw the tank. Forget about it.

For cycling, what product are you useinge? Unless its Bio-Spera its pointless. The others ones dont work at all.

Now, why do you want to lower them? 7.2 is perfect for most fish.

Kas is right, a black ghost knife will get too big for a 55 gallon.
You're doing good using the ammonia to start the cycle, but the majority of the commercial cycle products are snake oil. Your tap water looks great for what you want. I was thinking about using peat to down my ph (which is 8ish) and hardness, which is off the scale, and what I've learned is that the most important thing is to have a stable pH and if you are modifying it you run more of a risk in fluctuations that are harder on your fish that the higher pH and hardness. Most likely if you are buying fish at your LFS they are already in the type of water taht comes out of your tap.

And why are you adding salt? The reduction im TDS by peat extraction you are more than compensating for by boosting the TDS with salt. Sounds like a bad idea to me. Take nursie's advice and also drop the salt.

Buy some pop, drink pop. Rinse bottles. Fill 1/2-3/4 with water and freeze. Place one in tank. Alternate bottles as necessary. This should help to keep the temperature down.

and stop using salt

Beating the heat: http://www.aquariacentral.com/forums/showthread.php?t=52858

h20

Use ro water aka reverse osmosis Most fish stores out here sell it by the 5 gallon.Our tap water runs about 8.0 Use ro on most of your water changes ,in 6 months or so use 50/50 ro -tap so your ph wont drop off the scale.Hey no chems. I run an ro system out of my shop 200 or so bucks at Home depo.

RO water is pure clean, void of any minerals. Fish do not live in super clean (aka RO water) in their natural enviroment. Certain trace elemnts found naturally in water must be present in order for a fish to be healthy as they use these elements in their immune system. RO water is used primarily by SW aquarist to remove phosphate and silicate, which can cause diatomin algae. If so you RO water for your FW tank make sure to add commercially sold product that re-introduce elements found in natural water.

99% of the FW fish you buy today are tank raised and thus able to hand wide range of pH. It is more important to maintain constant pH rather than trying match the pH value given in books and on the net for each specific fish.

According fishprofile.com, neon tetras couldn't be kept with guppies and platies due to different pH range needed. Yet I successfully kept all of them in my 29 gallon tank for over two years.

Rohn