Need help toilet will not flush, Just spins

[Gillian]

I hope this is the correct forum to post this at:
I Moved into a new apartment recently, and my toilet has yet to work properly, initially I believed it was plugged, but after plunging and pouring hot water down to have it drain successfully, I realized this doesn't seem the case. But anytime I do not add hot water to the bowl, it does not flush very well, the bowl fills up and slowly drains-with little affect to the content over 3-5mins after spinning.
I looked online already, and found various recommended solutions, from pouring CLR down to rid of limescale in the drain holes (or whatever they are called), I have even q-tipped them out to clean them, this does not seem to be the issue.
I have looked in the tank of course, and it seems to be a different kind of system than everybody has mentioned: with no chain or black bulb, just a pump of some sort and another piece I don't recognize- obviously I know very little about the subject, and have never had the issue of repairing any plumbing equipment until now.
I have bought various plungers now, a heavy duty funnel one, and a CO2 one as well, both seem the only way to get my toilet to flush properly now when the water is forced out.
As a student I would dearly like to avoid having to call a plumber if the solution is solvable on my own. Any possible solutions or help would be greatly appreciated.

I included an image to the thread, since I do not know the name of the parts or how to describe it.

 

[Gary Swart]

The likely problem is a clogged drain. Chemicals will not clear it. Plunging will not clear a clogged drain. It requires a professional plumber to clear the clog. DIY snakes are not capable of doing the job, they usually just push it deeper and compact it tighter. I will tell you that the chemical you are putting into the tank is very harmful to the rubber parts in the tank. Toilet manufactures advise against them. You should avoid flushing anything that is not human waste or toilet paper.

 

[Sponsor]

 

[Gillian]

The likely problem is a clogged drain. Chemicals will not clear it. Plunging will not clear a clogged drain. It requires a professional plumber to clear the clog. DIY snakes are not capable of doing the job, they usually just push it deeper and compact it tighter. I will tell you that the chemical you are putting into the tank is very harmful to the rubber parts in the tank. Toilet manufactures advise against them. You should avoid flushing anything that is not human waste or toilet paper.

Fun story, I just solved it like 5 mins ago. realized I could change the water level in the tank, did so, and after about two weeks of lowflow trouble, It now flushed just fine.
But I do appreciate the help, and thank you for the information, I will not be using CLR on the toilet again. So glad I didn't have to hire a plumber.

 

[Terry]

Normally the water level in the tank will be about 1/2" from the top of the overflow tube.
What you have is a Mansfield toilet, with their flush valve, and a Fluidmaster fill valve.