I dont think thats how those work. It should only react to the PH of the water. Dont think the dye will effect it that much. I still recommend a PH meter otherwise you will continue to guess and potentially harm your plant. I tried to grow my first plant without one. About half way through I started to have problems, got a PH meter and found out that the water that I thought was within range was actually sitting at about 6.8. Fixed that and presto back on track. After having a meter I noticed alot of things can effect the PH and it WILL change everyday. So you really need to stay on top of it or you will regret it. Best of luck to you