You do not need to mess with your PH at this point. PH of 6.0 is perfectly fine for fishless cycling. There is nothing to worry about until you suddenly see PH 5.0 or lower.
You need to know that many people have tap water of PH around 6.0 in their area. They don't have a problem with their aquarium nitrogen cycle.
Even when your aquarium water PH had truly crashed to 5.0 or below, a simple partial water change of 30~50% will restore your water PH and buffer. No need for egg shell or any other methods. Not to mention egg shell method is for long term, it is not an immediate solution. Definitely stay away from those "PH up" or "PH down" chemical products, they will just mess up your aquarium and do no good at all.
Not to mention egg shell method is for long term, it is not an immediate solution. Definitely stay away from those "PH up" or "PH down" chemical products, they will just mess up your aquarium and do no good at all.
