whats your ph before co2 injection aka out the tap?To make my 4dkh i used tap water and distilled water, mixed both until i got a 4dkh solution. I'm not sure if this a proper way to make a solution but each time i test the solution, once a month, it reads 4dkh. Not sure how the tap water plays into it, but its green and been running for 2 months. I test my tank ph to make sure I'm not ODing on co2 and so far the readings stay at 7.0
To make my container i used a plastic cough medicine cup and some tubing.