LED Lights Power Issue
Awfully long distance to carry power without feeder

OK, so you've got five 5m segments of LED strips, all wired elephant style nose to tail, also called daisy chained, creating a single 25m super LED strip.   That itself has some problems, because the internal power buses of those LED strips are not rated or intended for unlimited length.  They can only support 2 LED strips (10m) in daisy chain like that.  Since you are feeding both ends, you have effectively 2.5m.  This means you have a fair chance of burning up the printed-circuit board traces near the ends of your super 25m strip.  If one end burns out, that will throw all the current onto the other end, causing it to burn up almost immediately. 

You will definitely have noticeable fading down the line, with the strips brightest where fed, and dimmest at the far end of course.  

The curative for both problems is to run feeder. That is wires run in parallel to the strips, which tie in to the strips at certain intervals, e.g. every 5 metres would be ideal. You'd need 4 wires for R G B and Common, and the Common wire is most important since it handles 3x the current of the others. 

Awful lot of load for a a controller

That thing that does dimming on each R G B channel independently to produce the colors you want, that is called a controller. Most controllers will support 1 or 2 LED strips at the outside.  

For the bog-standard 300-LED per 5m (60 LED per metre) 12 volt strip, those generally draw 0.4 A per metre per channel.  Yours has 3 channels.  So at 25M I calculate 10A per channel, or 30A for all.  Note that the common wire/trace needs to handle all 30A, or 15A per half.

Now I'm looking at the specs for the model of LED controller that all the sharks are selling on Amazon Marketplace (it's the same controller).   It says 4A per channel, with 100W (8.33A) absolute maximum all channels added up.  I do see one that looks to support 10A per channel, but its terminal connections look stupidly small to carry 30A on the common.  I would expect that to burn up. 

That's an awful lot of power, too

As said, the strips you have installed will pull 30A wide-open.  If you're using a Tier I supplier like GE or Siemens, you can probably get a power supply that delivers 125% of that, or 37A.  If you're using a lesser supplier like Meanwell, aim for 200% or 60A.  And if dealing with the Alibaba junkstream (found on Amazon Marketplace, eBay, Banggold, etc.), then 300% or 90A, because you can't expect reliability from that junk.