Double sided tape and emergency blankets work good for cheap wall coverage and hold less heat then that foil. I got a 12pak off amazon for $12 free shipping the tape it the expensive part around $5 a roll might need 2 blankets and 2 rolls to do that area or just use a staple gun. Also if you cut up a milk jug or plastic pop bottle they work good as buffers and makes the blanket a little less likely to tare spreads pressure around the staple instead of being only focused at staple. I like them a lot i know they arne't as good as some other coverages but 12 bucks will do that grow at least 6 times 5-10 bucks in tape each time makes it cheap to clean between grows or on a monthly schedule. Im sub'd up buddy looking forward to the show
Do you ph your water/feed mixes try to get up a pic of your plants when the hps is off maybe take them in the bathroom or something so we can see in blue light hard to see in that hps but i love HPS bud porn.