API Implementation + Bug Fixes + Mysql and Cronjob Optimization on Finished website project!

I need a part-time developer who is able to fix some bugs + add a few new lines of code to an existing website. If the work I need is done quickly and professionally (without leaving new BUGS behind please), I really have a lot of more work to give out. But I first want to see coding skills before giving out more. If you think that you will need more then 1-3 working days for the points described quickly below...please do not apply for this job (as the work is not hard if you have the proper skills). I set my Budget for this at 100$ as it can be completed in HOURS (and if you are from India for example, 100$ is the same as 450$ in my country...so 100$ should really be enough to perform this "test work") Quick notes I can give about the website: the framework is "Codeigniter" and the website basically displays data that is fetched from various API's updating it automatically every 5 minutes. It is listing "Cryptocoins" (you don't really have to understand what they are but it would be better) by numeric values. Check it out and try to understand how it works before applying for this job please (AND MAKE SURE TO SPEAK GOOD ENGLISH PLEASE): [login to view URL] Things I need to be done as quickly as possible (more detailed description will be sent to person I choose, but this should be enough for you to understand the issue already) 1) Query and Cronjob optimization. The website should update all the data (an positions, like in music charts websites) every 5 minutes but somehow the data is too much by now and it seems "stuck" and does not update every 5 minutes anymore (but every 15-20 or so). So probably something needs to be tuned here (I've done some optimization for Mysql already but it's not enough). Also some crons keep going down and this so I need somebody to look into this asap. 2) API Implementation - just one more array that says "if the price is below 0.00000001 BTC use LTC as base price instead" 3) each of the coins you see listed on the main page has a "minted coins" number. This number is updated every 5 minutes from a link I add in my admin interface. A coin cannot participate in the ranking if this number is not available. But it should be if I insert this number manually (as for now it only works if the link is present)This won't let me include a coin with a "Fixed supply" (coins that do not even need the supply link). I will also need a field where I can subtract a fix number from the supply output before it's used to calculate MCAP (mintedcoins*price). This point is really doable in a few minutes, it takes longer to explain than to do it. 3a) The limls that display this "total minted" number sometimes go offline. When this happens, the website behaves wrongly. It shows "?" in the 24hMCAPchange or the stat just freezes. This is illogic. The "minted coins" number should freeze to the last available before the link went down. But this still will let the website show the 24hMCAPchange (I have an example website that I will show you where this easy function is working) 4) Pagination. I want the page divided into "100" coins each page. Obviously it should be a clean Ajax pagination like for the "currency tabs" in the upper right corner. There is also a "calculator" form on the right side, it should still work after pagination. 5) Smaller fixes that I can tell you directly through IM while working on the site as most are solved with less than a line of code (examples: place a link in the upper right corner, add a dynamic alt tag to an image, change the "field type" of some MySQL table fields, change the "default vallue" for those fields etc..) 6) Some optimization as suggested by Google Speed Insights like loading images from another domain, deferring JS etc. I know a lot about website SEO and Optimization. I still would prefer if you have more knowledge than me, else I will advise you how to optimize it I prefer a Freelancer directly to a "Project Manager" considering more flexible working hours.