I found glass containers in the same shape/dimensions as the Grobo nute containers. Might come in handy for those using non-Grobo nutes. You can have 8oz of each of your nutes right there in the Grobo.
I will look into it if I have to later. I use my refill bucket now and the Grobo nutrients PH as needed. The Grobo bottles are barely touched so far.
Which nutrients are you using in place of bottles 3-5 in your bucket?
Many most are in Harley Smith’s seminars on YouTube