I'm running a 30 Gallon reef tank (been up and running for about 3.5 months now) and keep encountering pH levels that are lower than recommended/normal and I fear what long term effects this will have on my fish/corals. All other parameters in my tank have been testing at normal levels but my pH runs relatively at about 7.4 to 7.5 on any given day. Everything in my tank looks healthy and happy at least, but I obviously want to do my best to provide the best quality water chemistry I can for my stock in order for it to thrive well in the long run.
After performing hours of online research I tested a couple theories and still have no real answers.
First I took into account that gas exchange may have a negative effect on maintaining my pH levels so I measured the pH of my tank water (7.5 as usual) and removed a glass full and aerated it with an airstone for an hour, then remeasured the pH of the water in the glass and there was no change. This was not really all that surprising to me though as I have adequate water movement throughout the tank (377 GPH
) and one of my power-heads is specifically positioned upward to break the water tension and remove the chance of poor gas exchange in my water (also no lid for better oxygen flow).
Second I read in multiple places that using liquid Amquel can lower pH quite drastically in certain water conditions. I usually was using it to treat my tap water before water changes so I thought perhaps this was the culprit. I measured the pH of my tap water right out of the sink and it read at 8.7 pH.
Then after adding proper amounts of marine salt and Amquel to a 5 gallon bucket of tap water, I remeasured and it dropped down to 7.5 as expected. So for a moment I was convinced it was the Amquel. I dumped that bucket of water and made a new batch, this time I treated the water with Prime first - which, when added on its own into the freshwater had no effect on my tap's pH levels as they still read at about 8.7 but as soon as I mixed in my marine salt it dropped back down to 7.5!
Is it possible that the marine salt is having this effect? And if so why/how and what can be done about it? Or am I just an incredibly dumb newbie who is missing something really obvious? Any clues as to why this is happening would be very much appreciated! And apologies in advanced if this is a dumb question...