Can someone help me with my tank water?

[Kseries4]

I treated my water with aquasafe new with bioextract. Today, I used sentry aq mardel 5 in 1 test strips. Nitrate is good. Total hardness is Hard 150, is that okay? Total alkalinity is High 300, how can I fix that? pH also says High 8.5, how do i fix that or do I have to? Im going to have some fish from the petstore, not 100% sure what though. Its a 20 gallon tank.
Im kind of on a budget right now, so if i didnt HAVE to go out and buy any chemicals thatd be great, but if I do, ill do it. I do know about the nitrogren cycle.

 

[OrangeCones]

What is 'good' for a nitrate reading?

Are you planning on doing a fishless cycle (most humane) or a fish-in cycle?

 

[KcMopar]

Do you have any fish in it? If not do a fish-less cycle and for go the chemicals. Just toss in a chunk of peeled shrimp and let nature takes it coarse.

 

[Kseries4]

It is a fishless cycle and I have thrown a few fish flakes in there. I read a few things that said fish flakes would do.
I'm also kind of having trouble with my submersible heater. It came with the tank and 0 instructions.

 

[OrangeCones]

What kind of trouble with the heater?

 

[Kseries4]

There's a little red knob at the top that's above a + and - sign. When it's all way to the +, the coils turn red. But when I turn it to the -, they turn off. It did make the temperature go down a little, which I needed, but it's not below 84. The thermometer isn't even that reliable. When I put it in, the tabs with numbers used to change colors to indicate what the temperature was, but now it's just black. It's one of those that you stick inside the tank.

 

[gabegarcia00]

a good way to lower the ph is to place some peat moss inside your filter. Driftwood is also a good way to cut down your ph. Although depending on the fish you decide to go with you may not need to change it at all. Honestly its better to keep your ph steady than to have to try and keep it lower than your local water supply. As far as your alkalinity level that would also depend on the fish you choose. Some require high levels and some require otherwise. Just make sure you do your research on the fish you choose. Always easier to stick with fish that are compatible with your local water. Hope this helps, Good luck. Oh and i agree with mckopar on the fishless cycle with the peeled shirmp, works quick and so simple