Alkalinity? and chiller

I just want to understand something, what is alkalinity?

I had to look it up to see how to spell it and I don’t know what it is really, the explanation on the net was very hard to understand!

Another thing is we had some warm days recently and the tank wasn't looking so good so my mum wants to buy us something that is supposed to help on hot days, to help make sure my son has a good tank to enjoy.
Where is the best place to get a chiller, at the best price and the people need to be helpful as well.
Are these like a fridge or something?

Hi Mandy and son!

Alkalinity is pretty much what is measured by the way in which acids are neutralized in your tank water, or how much they are neutralized.
Alkalinity and calcium go hand in hand more or less and calcium helps stabilise the PH as it is a positive ion between the base and the acid a negative ion,alkalinity is the measurement of the other end of the PH called the acid, the gap in between the base and the acid is what is measured as PH.
Its not really an issue if the carbon dioxide levels in your tank remain constantly low and your pH remains 8.1-8.5,any where in that range is good.
Alkalinity, just say that it is the acid levels with in the measure of PH,in its simplest term.

The chiller would most likely be best sourced at age of aquariums, yes they are our sponsor, but Ben, the owner, has excellent low prices, just give them the size of your tank and take the next size up that they recommend if they say that would just do it.
In a month or so your tank will suffer a great deal if you do not have a chiller.